patch bump

CMakeLists.txt

@@ -381,10 +381,11 @@ else()
     set(ARMA_LIBS ${ARMA_LIBS} ${MKL_LIBRARIES})
     
     message(STATUS "")
-    message(STATUS "*** If the MKL libraries are installed in non-standard locations such as")
+    message(STATUS "*** If the MKL libraries are installed in a non-standard location such as")
     message(STATUS "*** /opt/intel/mkl, /opt/intel/composerxe/, /usr/local/intel/mkl")
     message(STATUS "*** make sure the run-time linker can find them.")
     message(STATUS "*** On Linux systems this can be done by editing /etc/ld.so.conf")
+    message(STATUS "*** or specifying the location through a file in /etc/ld.so.conf.d/")
     message(STATUS "*** or modifying the LD_LIBRARY_PATH environment variable.")
     message(STATUS "")
     message(STATUS "*** On systems with SELinux enabled (eg. Fedora, RHEL),")
@@ -419,10 +420,11 @@ else()
       endif()
       
       message(STATUS "")
-      message(STATUS "*** If the OpenBLAS library is installed in")
+      message(STATUS "*** If the OpenBLAS library is installed in a location such as")
       message(STATUS "*** /usr/local/lib or /usr/local/lib64")
       message(STATUS "*** make sure the run-time linker can find it.")
       message(STATUS "*** On Linux systems this can be done by editing /etc/ld.so.conf")
+      message(STATUS "*** or specifying the location through a file in /etc/ld.so.conf.d/")
       message(STATUS "*** or modifying the LD_LIBRARY_PATH environment variable.")
       message(STATUS "")
       

README.md

@@ -38,7 +38,8 @@ Copyright 2017-2025 Data61 / CSIRO
 13. [API Stability and Version Policy](#13-api-stability-and-version-policy)
 14. [Bug Reports and Frequently Asked Questions](#14-bug-reports-and-frequently-asked-questions)
 
-15. [Related Software Using Armadillo](#15-related-software-using-armadillo)
+15. [Prohibition on Use of Large Language Models (LLMs)](#15-prohibition-on-use-of-large-language-models-llms)
+16. [Related Software Using Armadillo](#16-related-software-using-armadillo)
 
 ---
 
@@ -390,8 +391,8 @@ Use a web browser to view it.
 
 Use of the C++11 `auto` keyword is not recommended with Armadillo objects and expressions.
 
-Armadillo has a template meta-programming framework which creates short-lived temporaries
-that are not properly handled by `auto`.
+Armadillo has a template meta-programming framework which creates short-lived
+temporary objects that are not properly handled by `auto`.
 
 ---
 
@@ -451,7 +452,16 @@ https://arma.sourceforge.net/faq.html
 
 ---
 
-### 15: Related Software Using Armadillo
+### 15: Prohibition on Use of Large Language Models (LLMs)
+
+The Armadillo codebase has been developed entirely without the use of LLMs.
+We do not accept any code which has been created (directly or indirectly)
+with the aid of LLMs. This is due to issues with code provenance and low quality
+of LLM generated code.
+
+---
+
+### 16: Related Software Using Armadillo
 
 * MLPACK: extensive library of machine learning algorithms  
   https://mlpack.org

docs.html

@@ -21,6 +21,15 @@ limitations under the License.
   <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
   <title>Armadillo: API Documentation</title>
   <link rel="icon" type="image/png" href="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAAXNSR0IArs4c6QAAAAlwSFlzAAALEwAACxMBAJqcGAAAARpJREFUOMtjYMABzFuiGYE4BohPA/FvIP6Phv8CMTcuzVxAvAGqeTYQT0HCd6AG3MSlmRWIdwNxLhY5MyC+ADVgLS4DyqAK2NDEBaAuiobKt+Ay4CZUgQRaeKwCYj8gTofKR+My4CNUQSSSWCYQT4ay+6HyprgMOADEs4BYFso3AOITQMwB5W+HGsCPMxCR2LxAfA6INZHE7gHxGwZCAOrvFUDcCsQqUKwFxP+A+CQxBpRgSTwwvIKQZm8gfgbEVkCsgYRToQZ049NsBtVshEUuA2pAAYpfoTQzEEcB8QsgtsdheA/UgFhkwV1AfBuIPwDxOyC2xeO6jVAD5kBd6gQS/AbEX4F4JRDLEwgbUHp4CsRboLETzkApAADMF8+Pl3d18QAAAABJRU5ErkJggg==">
+  <script type="application/rsl+xml">
+    <rsl xmlns="https://rslstandard.org/rsl">
+      <content url="">
+        <license>
+          <prohibits type="usage">ai-train ai-input</prohibits>
+        </license>
+      </content>
+    </rsl>
+  </script>
   <style type="text/css">
   <!--
 body
@@ -245,8 +254,9 @@ Conrad Sanderson and Ryan Curtin.
 <tr><td><a href="#Col">Col&lt;<i>type</i>&gt;, colvec, vec</a></td><td>&nbsp;</td><td>dense column vector class</td></tr>
 <tr><td><a href="#Row">Row&lt;<i>type</i>&gt;, rowvec</a></td><td>&nbsp;</td><td>dense row vector class</td></tr>
 <tr><td>&nbsp;</td><td>&nbsp;</td><td>&nbsp;</td></tr>
-<tr><td><a href="#Cube">Cube&lt;<i>type</i>&gt;, cube, cx_cube</a></td><td>&nbsp;</td><td>dense cube class ("3D matrix")</td></tr>
+<tr><td><a href="#Cube">Cube&lt;<i>type</i>&gt;, cube, cx_cube</a></td><td>&nbsp;</td><td>dense cube class (quasi third-order tensor, aka "3D matrix")</td></tr>
 <tr><td><a href="#field">field&lt;<i>object&nbsp;type</i>&gt;</a></td><td>&nbsp;</td><td>class for storing arbitrary objects in matrix-like or cube-like layouts</td></tr>
+<tr><td>&nbsp;</td><td>&nbsp;</td><td>&nbsp;</td></tr>
 <tr><td><a href="#SpMat">SpMat&lt;<i>type</i>&gt;, sp_mat, sp_cx_mat</a></td><td>&nbsp;</td><td>sparse matrix class</td></tr>
 <tr><td>&nbsp;</td><td>&nbsp;</td><td>&nbsp;</td></tr>
 <tr><td><a href="#operators">operators</a></td><td>&nbsp;</td><td><code><big>+</big>&nbsp; <big>&minus;</big>&nbsp; <big>*</big>&nbsp; %&nbsp; /&nbsp; ==&nbsp; !=&nbsp; &lt;=&nbsp; &gt;=&nbsp; &lt;&nbsp; &gt;&nbsp; &amp;&amp;&nbsp; ||</code></td></tr>
@@ -751,6 +761,8 @@ Functions which use LAPACK (generally matrix decompositions) are only valid for
 <a name="constructors_mat"></a>
 <li>
 Constructors:
+<br>
+<br>
 <ul>
 <table>
 <tbody>
@@ -775,22 +787,27 @@ Constructors:
 <li>
 Matrix elements can be explicitly initialised during construction by specifying <i>fill_form</i>,
 which is one of:
+<br>
+<br>
 <ul>
 <table>
 <tbody>
-<tr><td><code>fill::zeros</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to 0</td></tr>
-<tr><td><code>fill::ones</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to 1</td></tr>
-<tr><td><code>fill::eye</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set the elements on the main diagonal to 1 and off-diagonal elements to 0</td></tr>
-<tr><td><code>fill::randu</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to random values from a uniform distribution in the [0,1] interval</td></tr>
-<tr><td><code>fill::randn</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to random values from a normal/Gaussian distribution with zero mean and unit variance</td></tr>
-<tr><td><code>fill::value(scalar)</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to specified scalar</td></tr>
 <tr><td><code>fill::none</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>do not initialise the elements &nbsp; (matrix may have garbage values)</td></tr>
+<tr><td><code>fill::zeros</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to 0 &nbsp; (default operation)</td></tr>
+<tr><td><code>fill::ones</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to 1</td></tr>
+<!-- <tr><td><code>fill::nan</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to NaN</td></tr> -->
+<!-- <tr><td><code>fill::pos_inf</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to +infinity</td></tr> -->
+<!-- <tr><td><code>fill::neg_inf</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to -infinity</td></tr> -->
+<tr><td><code>fill::value(scalar)</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to the specified scalar</td></tr>
+<tr><td><code>fill::eye</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set elements on the main diagonal to 1 and off-diagonal elements to 0</td></tr>
+<tr><td><code>fill::randu</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set elements to random values from a uniform distribution in the [0,1] interval</td></tr>
+<tr><td><code>fill::randn</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set elements to random values from a normal/Gaussian distribution with mean&thinsp;=&thinsp;0 and variance&thinsp;=&thinsp;1</td></tr>
 </tbody>
 </table>
 </ul>
 </li>
 <br>
-<li>Default element initialisation is <code>fill::zeros</code> (since Armadillo 10.5)</li>
+<li>If <i>fill_form</i> is not specified, <i>fill::zeros</i> is used by default (since Armadillo 10.5)</li>
 <br>
 <li>
 For the <i>mat(string)</i> constructor, the format is elements separated by spaces, and rows denoted by semicolons;
@@ -1145,6 +1162,8 @@ main exceptions are functions which require square matrices
 <br>
 <li>
 Constructors:
+<br>
+<br>
 <ul>
 <table>
 <tbody>
@@ -1417,6 +1436,8 @@ main exceptions are functions which require square matrices
 <br>
 <li>
 Constructors:
+<br>
+<br>
 <ul>
 <table>
 <tbody>
@@ -1543,11 +1564,11 @@ rowvec z = A.row(5); // extract a row vector
 <br><b>cx_cube</b>
 <ul>
 <li>
-Classes for cubes (quasi 3rd order tensors), also known as "3D matrices"
+Classes for cubes (quasi third-order tensors, aka "3D matrices")
 </li>
 <br>
 <li>
-Data is stored as a set of slices (matrices) stored contiguously within memory;
+Data is stored as an ordered set of slices (matrices) placed contiguously within memory;
 within each slice, elements are stored with column-major ordering (ie. column by column)
 </li>
 <br>
@@ -1695,6 +1716,8 @@ it is possible to use other types instead, eg. <i>fcube</i>
 <a name="constructors_cube"></a>
 <li>
 Constructors:
+<br>
+<br>
 <ul>
 <table>
 <tbody>
@@ -1713,21 +1736,26 @@ Constructors:
 <li>
 Cube elements can be explicitly initialised during construction by specifying <i>fill_form</i>,
 which is one of:
+<br>
+<br>
 <ul>
 <table>
 <tbody>
-<tr><td><code>fill::zeros</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to 0</td></tr>
-<tr><td><code>fill::ones</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to 1</td></tr>
-<tr><td><code>fill::randu</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to random values from a uniform distribution in the [0,1] interval</td></tr>
-<tr><td><code>fill::randn</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to random values from a normal/Gaussian distribution with zero mean and unit variance</td></tr>
-<tr><td><code>fill::value(scalar)</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to specified scalar</td></tr>
 <tr><td><code>fill::none</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>do not initialise the elements &nbsp; (cube may have garbage values)</td></tr>
+<tr><td><code>fill::zeros</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to 0 &nbsp; (default operation)</td></tr>
+<tr><td><code>fill::ones</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to 1</td></tr>
+<!-- <tr><td><code>fill::nan</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to NaN</td></tr> -->
+<!-- <tr><td><code>fill::pos_inf</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to +infinity</td></tr> -->
+<!-- <tr><td><code>fill::neg_inf</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to -infinity</td></tr> -->
+<tr><td><code>fill::value(scalar)</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set all elements to the specified scalar</td></tr>
+<tr><td><code>fill::randu</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set elements to random values from a uniform distribution in the [0,1] interval</td></tr>
+<tr><td><code>fill::randn</code></td><td>&nbsp;&mapsto;&nbsp;</td><td>set elements to random values from a normal/Gaussian distribution with mean&thinsp;=&thinsp;0 and variance&thinsp;=&thinsp;1</td></tr>
 </tbody>
 </table>
 </ul>
 </li>
 <br>
-<li>Default element initialisation is <code>fill::zeros</code> (since Armadillo 10.5)</li>
+<li>If <i>fill_form</i> is not specified, <i>fill::zeros</i> is used by default (since Armadillo 10.5)</li>
 <br>
 <li>
 Each instance of <i>cube</i> automatically allocates and releases internal memory.
@@ -1863,6 +1891,8 @@ Each element can have an arbitrary size (eg. in a field of matrices, each matrix
 <br>
 <li>
 Constructors, where <i>object_type</i> is another class, eg. <i>vec</i>, <i>mat</i>, <i>std::string</i>, etc:
+<br>
+<br>
 <ul>
 <table>
 <tbody>
@@ -1889,6 +1919,7 @@ mat A = randn(2,3);
 mat B = randn(4,5);
 
 field&lt;mat&gt; F(2,1);
+
 F(0,0) = A;
 F(1,0) = B; 
 
@@ -2063,6 +2094,8 @@ it is possible to use other types instead, eg. <i>sp_fmat</i>
 <a name="constructors_sp_mat"></a>
 <li>
 Constructors:
+<br>
+<br>
 <ul>
 <table>
 <tbody>
@@ -2100,6 +2133,8 @@ for small matrices use the <a href="#Mat">Mat</a> class, even if most of the ele
 <li>
 <a name="batch_constructors_sp_mat"></a>
 Batch insertion constructors:
+<br>
+<br>
 <ul>
 <li>form&nbsp;1: <code>sp_mat(<i>locations</i>, <i>values</i>, <i>sort_locations&thinsp;=&thinsp;true</i>)</code></li>
 <li>form&nbsp;2: <code>sp_mat(<i>locations</i>, <i>values</i>, <i>n_rows</i>, <i>n_cols</i>, <i>sort_locations&thinsp;=&thinsp;true</i>, <i>check_for_zeros&thinsp;=&thinsp;true</i>)</code></li>
@@ -2153,6 +2188,8 @@ If <i>check_for_zeros</i> is set to <i>false</i>, the <i>values</i> vector is as
 <br>
 <li>
 The following subset of operations &amp; functions is available for sparse matrices:
+<br>
+<br>
 <ul>
 <li>fundamental arithmetic <a href="#operators">operations</a> (such as addition and multiplication)</li>
 <li><a href="#submat">submatrix views</a>: most contiguous forms and the non-contiguous form of <i>X.cols(vector_of_column_indices)</i></li>
@@ -2932,6 +2969,7 @@ C.eye();
 <li>See also:
 <ul>
 <li><a href="#ones_member">.ones()</a></li>
+<li><a href="#fill">.fill()</a></li>
 <li><a href="#diag">.diag()</a></li>
 <li><a href="#diagmat">diagmat()</a></li>
 <li><a href="#diagvec">diagvec()</a></li>
@@ -3090,7 +3128,7 @@ See also:
 Member function of <i>Mat</i>, <i>Col</i>, <i>Row</i>, <i>Cube</i>, <i>field</i>
 </li>
 <br>
-<li>Sets the elements to a specified value</li>
+<li>Sets all elements to a specified value</li>
 <br>
 <li>The type of value must match the type of elements used by the container object (eg. for <i>mat</i> the type is <i>double</i>)
 </li>
@@ -3101,29 +3139,38 @@ Examples:
 <pre>
 mat A(5, 6);
 
-A.fill(123.0);   // or:  mat A(5, 6, fill::value(123.0));
+A.fill(123.0);
 </pre>
 </ul>
 </li>
 <br>
 <li>
-<b>Note:</b> to set all elements to zero during matrix construction, use the following more compact form:
+<b>Caveats:</b>
+<ul>
+<li>To initialise all elements during matrix construction, it is more efficient to use a <i><a href="#Mat">fill_form</a></i>:
 <ul>
 <pre>
 mat A(5, 6, fill::zeros);
+mat B(5, 6, fill::ones);
+mat C(5, 6, fill::value(123.0));
 </pre>
 </ul>
 </li>
+<li>If <i>fill_form</i> is not specified, <i>fill::zeros</i> is used by default (since Armadillo 10.5)</li>
+</ul>
+</li>
 <br>
 <li>
 See also:
 <ul>
 <li><a href="#imbue">.imbue()</a></li>
-<li><a href="#ones_member">.ones()</a></li>
 <li><a href="#zeros_member">.zeros()</a></li>
+<li><a href="#ones_member">.ones()</a></li>
+<li><a href="#eye_member">.eye()</a></li>
 <li><a href="#randu_randn_member">.randu() &amp; .randn()</a></li>
 <li><a href="#replace">.replace()</a></li>
 <li><a href="#constants">constants (pi, nan, inf, ...)</a></li>
+<li><a href="#Mat">matrix constructors</a></li>
 </ul>
 </li>
 <br>
@@ -4071,8 +4118,8 @@ Instances of <i>span(a,b)</i> can be replaced by:
 </li>
 <br>
 <li>
-An individual slice, accessed via <i>.slice()</i>, is an instance of the <i>Mat</i> class
-(a reference to a matrix is provided)
+A single slice, accessed via <i>.slice(slice_number)</i>, is an instance of the <i>Mat</i> class (a reference to a matrix is provided);
+<br>see also <i>.<a href="#col_row_as_mat">col_as_mat()</a></i> and <i>.<a href="#col_row_as_mat">row_as_mat()</a></i>
 </li>
 <br>
 <li>
@@ -5805,6 +5852,7 @@ Examples:
 <ul>
 <pre>
 mat X(4, 5, fill::randu);
+
 vec v = X.as_col();
 </pre>
 </ul>
@@ -5858,9 +5906,11 @@ Examples:
 <pre>
 cube Q(5, 4, 3, fill::randu);
 
-mat A = Q.col_as_mat(2);  // size of A: 5x3
+mat A = Q.slice(2);       // size of A: 5x4
 
-mat B = Q.row_as_mat(2);  // size of B: 3x4
+mat B = Q.col_as_mat(2);  // size of B: 5x3
+
+mat C = Q.row_as_mat(2);  // size of C: 3x4
 </pre>
 </ul>
 </li>
@@ -18427,7 +18477,7 @@ An instance of the class has the following member functions:
       </td>
       <td style="vertical-align: top;">
       return the number of seconds since the last call to <code>.tic()</code>,
-      with the returned number of seconds reduced by any freeze/unfreeze durations
+      with the number of seconds reduced by any freeze/unfreeze durations
       </td>
     </tr>
     <tr>

include/armadillo_bits/Col_meat.hpp

@@ -1344,6 +1344,10 @@ Col<eT>::fixed<fixed_n_elem>::fixed(const fill::fill_class<fill_type>&)
   if(is_same_type<fill_type, fill::fill_eye  >::yes)  { Mat<eT>::eye();   }
   if(is_same_type<fill_type, fill::fill_randu>::yes)  { Mat<eT>::randu(); }
   if(is_same_type<fill_type, fill::fill_randn>::yes)  { Mat<eT>::randn(); }
+  
+  if(is_same_type<fill_type, fill::fill_nan    >::yes)  { (*this).fill( priv::Datum_helper::nan    <eT>() ); }
+  if(is_same_type<fill_type, fill::fill_pos_inf>::yes)  { (*this).fill( priv::Datum_helper::pos_inf<eT>() ); }
+  if(is_same_type<fill_type, fill::fill_neg_inf>::yes)  { (*this).fill( priv::Datum_helper::neg_inf<eT>() ); }
   }
 
 

include/armadillo_bits/Cube_bones.hpp

@@ -360,6 +360,9 @@ class Cube : public BaseCube< eT, Cube<eT> >
   
   inline Cube& fill(const eT val);
   
+  template<typename fill_type>
+  inline Cube& fill(const fill::fill_class<fill_type>& f);
+  
   inline Cube& zeros();
   inline Cube& zeros(const uword new_n_rows, const uword new_n_cols, const uword new_n_slices);
   inline Cube& zeros(const SizeCube& s);

include/armadillo_bits/Cube_meat.hpp

@@ -52,7 +52,7 @@ Cube<eT>::Cube()
   , n_elem(0)
   , n_alloc(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   }
@@ -172,7 +172,7 @@ Cube<eT>::Cube(const SizeCube& s, const arma_initmode_indicator<do_zeros>&)
 template<typename eT>
 template<typename fill_type>
 inline
-Cube<eT>::Cube(const uword in_n_rows, const uword in_n_cols, const uword in_n_slices, const fill::fill_class<fill_type>&)
+Cube<eT>::Cube(const uword in_n_rows, const uword in_n_cols, const uword in_n_slices, const fill::fill_class<fill_type>& f)
   : n_rows(in_n_rows)
   , n_cols(in_n_cols)
   , n_elem_slice(in_n_rows*in_n_cols)
@@ -186,12 +186,7 @@ Cube<eT>::Cube(const uword in_n_rows, const uword in_n_cols, const uword in_n_sl
   
   init_cold();
   
-  if(is_same_type<fill_type, fill::fill_zeros>::yes)  { (*this).zeros(); }
-  if(is_same_type<fill_type, fill::fill_ones >::yes)  { (*this).ones();  }
-  if(is_same_type<fill_type, fill::fill_randu>::yes)  { (*this).randu(); }
-  if(is_same_type<fill_type, fill::fill_randn>::yes)  { (*this).randn(); }
-  
-  arma_static_check( (is_same_type<fill_type, fill::fill_eye>::yes), "Cube::Cube(): unsupported fill type" );
+  (*this).fill(f);
   }
 
 
@@ -199,7 +194,7 @@ Cube<eT>::Cube(const uword in_n_rows, const uword in_n_cols, const uword in_n_sl
 template<typename eT>
 template<typename fill_type>
 inline
-Cube<eT>::Cube(const SizeCube& s, const fill::fill_class<fill_type>&)
+Cube<eT>::Cube(const SizeCube& s, const fill::fill_class<fill_type>& f)
   : n_rows(s.n_rows)
   , n_cols(s.n_cols)
   , n_elem_slice(s.n_rows*s.n_cols)
@@ -213,12 +208,7 @@ Cube<eT>::Cube(const SizeCube& s, const fill::fill_class<fill_type>&)
   
   init_cold();
   
-  if(is_same_type<fill_type, fill::fill_zeros>::yes)  { (*this).zeros(); }
-  if(is_same_type<fill_type, fill::fill_ones >::yes)  { (*this).ones();  }
-  if(is_same_type<fill_type, fill::fill_randu>::yes)  { (*this).randu(); }
-  if(is_same_type<fill_type, fill::fill_randn>::yes)  { (*this).randn(); }
-  
-  arma_static_check( (is_same_type<fill_type, fill::fill_eye>::yes), "Cube::Cube(): unsupported fill type" );
+  (*this).fill(f);
   }
 
 
@@ -934,7 +924,7 @@ Cube<eT>::Cube
   , n_elem(0)
   , n_alloc(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -1064,7 +1054,7 @@ Cube<eT>::Cube(const subview_cube_slices<eT,T1>& X)
   , n_elem(0)
   , n_alloc(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2751,7 +2741,7 @@ Cube<eT>::Cube(const OpCube<T1, op_type>& X)
   , n_elem(0)
   , n_alloc(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
 
@@ -3048,7 +3038,7 @@ Cube<eT>::Cube(const mtOpCube<eT, T1, op_type>& X)
   , n_elem(0)
   , n_alloc(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -3144,7 +3134,7 @@ Cube<eT>::Cube(const GlueCube<T1, T2, glue_type>& X)
   , n_elem(0)
   , n_alloc(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -3401,7 +3391,7 @@ Cube<eT>::Cube(const mtGlueCube<eT, T1, T2, glue_type>& X)
   , n_elem(0)
   , n_alloc(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -3887,7 +3877,7 @@ arma_inline
 eT*
 Cube<eT>::slice_memptr(const uword uslice)
   {
-  return const_cast<eT*>( &mem[ uslice*n_elem_slice ] );
+  return access::rwp( mem + (uslice*n_elem_slice) );
   }
 
 
@@ -3898,7 +3888,7 @@ arma_inline
 const eT*
 Cube<eT>::slice_memptr(const uword uslice) const
   {
-  return &mem[ uslice*n_elem_slice ];
+  return mem + (uslice*n_elem_slice);
   }
 
 
@@ -3909,7 +3899,7 @@ arma_inline
 eT*
 Cube<eT>::slice_colptr(const uword uslice, const uword col)
   {
-  return const_cast<eT*>( &mem[ uslice*n_elem_slice + col*n_rows] );
+  return access::rwp( mem + (uslice*n_elem_slice + col*n_rows) );
   }
 
 
@@ -3920,7 +3910,7 @@ arma_inline
 const eT*
 Cube<eT>::slice_colptr(const uword uslice, const uword col) const
   {
-  return &mem[ uslice*n_elem_slice + col*n_rows ];
+  return mem + (uslice*n_elem_slice + col*n_rows);
   }
 
 
@@ -4227,6 +4217,30 @@ Cube<eT>::fill(const eT val)
 
 
 
+template<typename eT>
+template<typename fill_type>
+inline
+Cube<eT>&
+Cube<eT>::fill(const fill::fill_class<fill_type>&)
+  {
+  arma_debug_sigprint();
+  
+  arma_static_check( (is_same_type<fill_type, fill::fill_eye>::yes), "Cube::fill(): unsupported fill type" );
+  
+  if(is_same_type<fill_type, fill::fill_zeros>::yes)  { (*this).zeros(); }
+  if(is_same_type<fill_type, fill::fill_ones >::yes)  { (*this).ones();  }
+  if(is_same_type<fill_type, fill::fill_randu>::yes)  { (*this).randu(); }
+  if(is_same_type<fill_type, fill::fill_randn>::yes)  { (*this).randn(); }
+  
+  if(is_same_type<fill_type, fill::fill_nan    >::yes)  { (*this).fill( priv::Datum_helper::nan    <eT>() ); }
+  if(is_same_type<fill_type, fill::fill_pos_inf>::yes)  { (*this).fill( priv::Datum_helper::pos_inf<eT>() ); }
+  if(is_same_type<fill_type, fill::fill_neg_inf>::yes)  { (*this).fill( priv::Datum_helper::neg_inf<eT>() ); }
+  
+  return *this;
+  }
+
+
+
 template<typename eT>
 inline
 Cube<eT>&
@@ -5458,18 +5472,13 @@ template<typename eT>
 template<uword fixed_n_rows, uword fixed_n_cols, uword fixed_n_slices>
 template<typename fill_type>
 inline
-Cube<eT>::fixed<fixed_n_rows, fixed_n_cols, fixed_n_slices>::fixed(const fill::fill_class<fill_type>&)
+Cube<eT>::fixed<fixed_n_rows, fixed_n_cols, fixed_n_slices>::fixed(const fill::fill_class<fill_type>& f)
   {
   arma_debug_sigprint_this(this);
   
   mem_setup();
   
-  if(is_same_type<fill_type, fill::fill_zeros>::yes)  { Cube<eT>::zeros(); }
-  if(is_same_type<fill_type, fill::fill_ones >::yes)  { Cube<eT>::ones();  }
-  if(is_same_type<fill_type, fill::fill_randu>::yes)  { Cube<eT>::randu(); }
-  if(is_same_type<fill_type, fill::fill_randn>::yes)  { Cube<eT>::randn(); }
-  
-  arma_static_check( (is_same_type<fill_type, fill::fill_eye>::yes), "Cube::fixed::fixed(): unsupported fill type" );
+  (*this).fill(f);
   }
 
 

include/armadillo_bits/Mat_meat.hpp

@@ -49,7 +49,7 @@ Mat<eT>::Mat()
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   }
@@ -255,7 +255,7 @@ Mat<eT>::Mat(const arma_vec_indicator&, const uhword in_vec_state)
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   }
@@ -312,15 +312,10 @@ Mat<eT>::init_cold()
     const char* error_message = "Mat::init(): requested size is too large; suggest to enable ARMA_64BIT_WORD";
   #endif
   
-  arma_conform_check
-    (
-      (
-      ( (n_rows > ARMA_MAX_UHWORD) || (n_cols > ARMA_MAX_UHWORD) )
-        ? ( (double(n_rows) * double(n_cols)) > double(ARMA_MAX_UWORD) )
-        : false
-      ),
-    error_message
-    );
+  if( (n_rows > ARMA_MAX_UHWORD) || (n_cols > ARMA_MAX_UHWORD) )
+    {
+    arma_conform_check( ( (double(n_rows) * double(n_cols)) > double(ARMA_MAX_UWORD) ), error_message );
+    }
   
   if(n_elem <= arma_config::mat_prealloc)
     {
@@ -383,17 +378,10 @@ Mat<eT>::init_warm(uword in_n_rows, uword in_n_cols)
     const char* error_message_4 = "Mat::init(): requested size is too large; suggest to enable ARMA_64BIT_WORD";
   #endif
   
-  arma_conform_set_error
-    (
-    err_state,
-    err_msg,
-      (
-      ( (in_n_rows > ARMA_MAX_UHWORD) || (in_n_cols > ARMA_MAX_UHWORD) )
-        ? ( (double(in_n_rows) * double(in_n_cols)) > double(ARMA_MAX_UWORD) )
-        : false
-      ),
-    error_message_4
-    );
+  if( (in_n_rows > ARMA_MAX_UHWORD) || (in_n_cols > ARMA_MAX_UHWORD) )
+    {
+    arma_conform_set_error( err_state, err_msg, ( (double(in_n_rows) * double(in_n_cols)) > double(ARMA_MAX_UWORD) ), error_message_4 );
+    }
   
   arma_conform_check(err_state, err_msg);
   
@@ -468,7 +456,7 @@ Mat<eT>::Mat(const char* text)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -502,7 +490,7 @@ Mat<eT>::Mat(const std::string& text)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -690,7 +678,7 @@ Mat<eT>::Mat(const std::initializer_list<eT>& list)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -722,7 +710,7 @@ Mat<eT>::Mat(const std::initializer_list< std::initializer_list<eT> >& list)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -889,7 +877,7 @@ Mat<eT>::Mat(const Mat<eT>& in_mat, const arma_vec_indicator&, const uhword in_v
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint(arma_str::format("this: %x; in_mat: %x") % this % &in_mat);
   
@@ -1524,7 +1512,7 @@ Mat<eT>::Mat(const BaseCube<eT,T1>& X, const arma_vec_indicator&, const uhword i
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -1543,7 +1531,7 @@ Mat<eT>::Mat(const BaseCube<eT,T1>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -1990,7 +1978,7 @@ Mat<eT>::Mat(const Base<typename Mat<eT>::pod_type,T1>& A, const Base<typename M
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2010,7 +1998,7 @@ Mat<eT>::Mat(const Base<typename Mat<eT>::pod_type,T1>& A, const Base<typename M
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2055,7 +2043,7 @@ Mat<eT>::Mat(const subview<eT>& X, const arma_vec_indicator&, const uhword in_ve
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2278,7 +2266,7 @@ Mat<eT>::Mat(const subview_cube<eT>& x, const arma_vec_indicator&, const uhword
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2297,7 +2285,7 @@ Mat<eT>::Mat(const subview_cube<eT>& x)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2407,7 +2395,7 @@ Mat<eT>::Mat(const diagview<eT>& X, const arma_vec_indicator&, const uhword in_v
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2552,7 +2540,7 @@ Mat<eT>::Mat(const subview_elem1<eT,T1>& X, const arma_vec_indicator&, const uhw
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2571,7 +2559,7 @@ Mat<eT>::Mat(const subview_elem1<eT,T1>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2680,7 +2668,7 @@ Mat<eT>::Mat(const subview_elem2<eT,T1,T2>& X, const arma_vec_indicator&, const
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2699,7 +2687,7 @@ Mat<eT>::Mat(const subview_elem2<eT,T1,T2>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2808,7 +2796,7 @@ Mat<eT>::Mat(const SpBase<eT, T1>& m, const arma_vec_indicator&, const uhword in
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2827,7 +2815,7 @@ Mat<eT>::Mat(const SpBase<eT, T1>& m)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -2888,6 +2876,8 @@ Mat<eT>::operator+=(const SpBase<eT, T1>& m)
   
   arma_conform_assert_same_size(n_rows, n_cols, p.get_n_rows(), p.get_n_cols(), "addition");
   
+  if(p.get_n_nonzero() == 0)  { return *this; }
+  
   typename SpProxy<T1>::const_iterator_type it     = p.begin();
   typename SpProxy<T1>::const_iterator_type it_end = p.end();
   
@@ -2910,6 +2900,8 @@ Mat<eT>::operator-=(const SpBase<eT, T1>& m)
   
   arma_conform_assert_same_size(n_rows, n_cols, p.get_n_rows(), p.get_n_cols(), "subtraction");
   
+  if(p.get_n_nonzero() == 0)  { return *this; }
+  
   typename SpProxy<T1>::const_iterator_type it     = p.begin();
   typename SpProxy<T1>::const_iterator_type it_end = p.end();
   
@@ -2928,9 +2920,9 @@ Mat<eT>::operator*=(const SpBase<eT, T1>& m)
   {
   arma_debug_sigprint();
   
-  Mat<eT> z = (*this) * m.get_ref();
+  Mat<eT> tmp = (*this) * m.get_ref();
   
-  steal_mem(z);
+  steal_mem(tmp);
   
   return *this;
   }
@@ -3011,7 +3003,7 @@ Mat<eT>::Mat(const SpSubview<eT>& X, const arma_vec_indicator&, const uhword in_
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -3029,7 +3021,7 @@ Mat<eT>::Mat(const SpSubview<eT>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -3212,7 +3204,7 @@ Mat<eT>::Mat(const spdiagview<eT>& X, const arma_vec_indicator&, const uhword in
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5140,7 +5132,7 @@ Mat<eT>::Mat(const Gen<T1, gen_type>& X, const arma_vec_indicator&, const uhword
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5290,7 +5282,7 @@ Mat<eT>::Mat(const Op<T1, op_type>& X, const arma_vec_indicator&, const uhword i
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5312,7 +5304,7 @@ Mat<eT>::Mat(const Op<T1, op_type>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5441,7 +5433,7 @@ Mat<eT>::Mat(const eOp<T1, eop_type>& X, const arma_vec_indicator&, const uhword
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5669,7 +5661,7 @@ Mat<eT>::Mat(const mtOp<eT, T1, op_type>& X, const arma_vec_indicator&, const uh
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5688,7 +5680,7 @@ Mat<eT>::Mat(const mtOp<eT, T1, op_type>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5797,7 +5789,7 @@ Mat<eT>::Mat(const CubeToMatOp<T1, op_type>& X, const arma_vec_indicator&, const
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5818,7 +5810,7 @@ Mat<eT>::Mat(const CubeToMatOp<T1, op_type>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5941,7 +5933,7 @@ Mat<eT>::Mat(const SpToDOp<T1, op_type>& X, const arma_vec_indicator&, const uhw
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -5962,7 +5954,7 @@ Mat<eT>::Mat(const SpToDOp<T1, op_type>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -6091,7 +6083,7 @@ Mat<eT>::Mat(const mtSpReduceOp<eT, T1, op_type>& X, const arma_vec_indicator&,
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -6110,7 +6102,7 @@ Mat<eT>::Mat(const mtSpReduceOp<eT, T1, op_type>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -6219,7 +6211,7 @@ Mat<eT>::Mat(const Glue<T1, T2, glue_type>& X, const arma_vec_indicator&, const
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -6242,7 +6234,7 @@ Mat<eT>::Mat(const Glue<T1, T2, glue_type>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -6408,7 +6400,7 @@ Mat<eT>::Mat(const eGlue<T1, T2, eglue_type>& X, const arma_vec_indicator&, cons
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -6615,7 +6607,7 @@ Mat<eT>::Mat(const mtGlue<eT, T1, T2, glue_type>& X, const arma_vec_indicator&,
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -6634,7 +6626,7 @@ Mat<eT>::Mat(const mtGlue<eT, T1, T2, glue_type>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -6745,7 +6737,7 @@ Mat<eT>::Mat(const SpToDGlue<T1, T2, glue_type>& X, const arma_vec_indicator&, c
   , n_alloc(0)
   , vec_state(in_vec_state)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -6767,7 +6759,7 @@ Mat<eT>::Mat(const SpToDGlue<T1, T2, glue_type>& X)
   , n_alloc(0)
   , vec_state(0)
   , mem_state(0)
-  , mem()
+  , mem(nullptr)
   {
   arma_debug_sigprint_this(this);
   
@@ -7487,7 +7479,7 @@ arma_inline
 eT*
 Mat<eT>::colptr(const uword in_col)
   {
-  return & access::rw(mem[in_col*n_rows]);
+  return access::rwp( mem + (in_col*n_rows) );
   }
 
 
@@ -7498,7 +7490,7 @@ arma_inline
 const eT*
 Mat<eT>::colptr(const uword in_col) const
   {
-  return & mem[in_col*n_rows];
+  return mem + (in_col*n_rows);
   }
 
 
@@ -7580,10 +7572,40 @@ Mat<eT>::resize(const uword new_n_elem)
   {
   arma_debug_sigprint();
   
-  const uword new_n_rows = (vec_state == 2) ? uword(1         ) : uword(new_n_elem);
-  const uword new_n_cols = (vec_state == 2) ? uword(new_n_elem) : uword(1         );
+  const bool reuse_mem = 
+    ( is_vec() && (mem_state == 0) )
+    &&
+    (
+         ( (new_n_elem <= arma_config::mat_prealloc) && (n_elem <= arma_config::mat_prealloc) && (    n_elem >  0      ) )
+      || ( (new_n_elem >  arma_config::mat_prealloc) && (n_elem >  arma_config::mat_prealloc) && (new_n_elem <= n_alloc) )
+    );
   
-  return (*this).resize(new_n_rows, new_n_cols);
+  if(reuse_mem)
+    {
+    arma_debug_print("Mat::resize(): reusing memory");
+    
+    if(new_n_elem > n_elem)
+      {
+      arma_debug_print("Mat::resize(): zeroing memory");
+      
+      eT* t_mem = (*this).memptr();   // the (n_elem > 0) check above ensures that (*this).memptr() is a valid pointer
+      
+      for(uword ii = n_elem; ii < new_n_elem; ++ii)  { t_mem[ii] = eT(0); }
+      }
+    
+    access::rw(n_rows) = (vec_state == 2) ? uword(1         ) : uword(new_n_elem);
+    access::rw(n_cols) = (vec_state == 2) ? uword(new_n_elem) : uword(1         );
+    access::rw(n_elem) = new_n_elem;
+    }
+  else
+    {
+    const uword new_n_rows = (vec_state == 2) ? uword(1         ) : uword(new_n_elem);
+    const uword new_n_cols = (vec_state == 2) ? uword(new_n_elem) : uword(1         );
+    
+    (*this).resize(new_n_rows, new_n_cols);
+    }
+  
+  return (*this);
   }
 
 
@@ -7908,6 +7930,10 @@ Mat<eT>::fill(const fill::fill_class<fill_type>&)
   if(is_same_type<fill_type, fill::fill_randu>::yes)  { (*this).randu(); }
   if(is_same_type<fill_type, fill::fill_randn>::yes)  { (*this).randn(); }
   
+  if(is_same_type<fill_type, fill::fill_nan    >::yes)  { (*this).fill( priv::Datum_helper::nan    <eT>() ); }
+  if(is_same_type<fill_type, fill::fill_pos_inf>::yes)  { (*this).fill( priv::Datum_helper::pos_inf<eT>() ); }
+  if(is_same_type<fill_type, fill::fill_neg_inf>::yes)  { (*this).fill( priv::Datum_helper::neg_inf<eT>() ); }
+  
   return *this;
   }
 
@@ -10081,6 +10107,10 @@ Mat<eT>::fixed<fixed_n_rows, fixed_n_cols>::fixed(const fill::fill_class<fill_ty
   if(is_same_type<fill_type, fill::fill_eye  >::yes)  { Mat<eT>::eye();   }
   if(is_same_type<fill_type, fill::fill_randu>::yes)  { Mat<eT>::randu(); }
   if(is_same_type<fill_type, fill::fill_randn>::yes)  { Mat<eT>::randn(); }
+  
+  if(is_same_type<fill_type, fill::fill_nan    >::yes)  { (*this).fill( priv::Datum_helper::nan    <eT>() ); }
+  if(is_same_type<fill_type, fill::fill_pos_inf>::yes)  { (*this).fill( priv::Datum_helper::pos_inf<eT>() ); }
+  if(is_same_type<fill_type, fill::fill_neg_inf>::yes)  { (*this).fill( priv::Datum_helper::neg_inf<eT>() ); }
   }
 
 
@@ -10515,7 +10545,7 @@ Mat<eT>::fixed<fixed_n_rows, fixed_n_cols>::colptr(const uword in_col)
   {
   eT* mem_actual = (use_extra) ? mem_local_extra : mem_local;
   
-  return & access::rw(mem_actual[in_col*fixed_n_rows]);
+  return access::rwp( mem_actual + (in_col*fixed_n_rows) );
   }
 
 
@@ -10528,7 +10558,7 @@ Mat<eT>::fixed<fixed_n_rows, fixed_n_cols>::colptr(const uword in_col) const
   {
   const eT* mem_actual = (use_extra) ? mem_local_extra : mem_local;
   
-  return & mem_actual[in_col*fixed_n_rows];
+  return mem_actual + (in_col*fixed_n_rows);
   }
 
 

include/armadillo_bits/Row_meat.hpp

@@ -1351,6 +1351,10 @@ Row<eT>::fixed<fixed_n_elem>::fixed(const fill::fill_class<fill_type>&)
   if(is_same_type<fill_type, fill::fill_eye  >::yes)  { Mat<eT>::eye();   }
   if(is_same_type<fill_type, fill::fill_randu>::yes)  { Mat<eT>::randu(); }
   if(is_same_type<fill_type, fill::fill_randn>::yes)  { Mat<eT>::randn(); }
+  
+  if(is_same_type<fill_type, fill::fill_nan    >::yes)  { (*this).fill( priv::Datum_helper::nan    <eT>() ); }
+  if(is_same_type<fill_type, fill::fill_pos_inf>::yes)  { (*this).fill( priv::Datum_helper::pos_inf<eT>() ); }
+  if(is_same_type<fill_type, fill::fill_neg_inf>::yes)  { (*this).fill( priv::Datum_helper::neg_inf<eT>() ); }
   }
 
 

include/armadillo_bits/SpMat_meat.hpp

@@ -688,15 +688,22 @@ SpMat<eT>::operator=(const SpMat<eT>& x)
 template<typename eT>
 inline
 SpMat<eT>&
-SpMat<eT>::operator+=(const SpMat<eT>& x)
+SpMat<eT>::operator+=(const SpMat<eT>& X)
   {
   arma_debug_sigprint();
   
   sync_csc();
   
-  SpMat<eT> out = (*this) + x;
-  
-  steal_mem(out);
+  if(X.n_nonzero == 0)
+    {
+    arma_conform_assert_same_size(n_rows, n_cols, X.n_rows, X.n_cols, "addition");
+    }
+  else
+    {
+    SpMat<eT> tmp = (*this) + X;
+    
+    steal_mem(tmp);
+    }
   
   return *this;
   }
@@ -706,15 +713,22 @@ SpMat<eT>::operator+=(const SpMat<eT>& x)
 template<typename eT>
 inline
 SpMat<eT>&
-SpMat<eT>::operator-=(const SpMat<eT>& x)
+SpMat<eT>::operator-=(const SpMat<eT>& X)
   {
   arma_debug_sigprint();
   
   sync_csc();
   
-  SpMat<eT> out = (*this) - x;
-  
-  steal_mem(out);
+  if(X.n_nonzero == 0)
+    {
+    arma_conform_assert_same_size(n_rows, n_cols, X.n_rows, X.n_cols, "subtraction");
+    }
+  else
+    {
+    SpMat<eT> tmp = (*this) - X;
+    
+    steal_mem(tmp);
+    }
   
   return *this;
   }
@@ -724,15 +738,15 @@ SpMat<eT>::operator-=(const SpMat<eT>& x)
 template<typename eT>
 inline
 SpMat<eT>&
-SpMat<eT>::operator*=(const SpMat<eT>& y)
+SpMat<eT>::operator*=(const SpMat<eT>& X)
   {
   arma_debug_sigprint();
   
   sync_csc();
   
-  SpMat<eT> z = (*this) * y;
+  SpMat<eT> tmp = (*this) * X;
   
-  steal_mem(z);
+  steal_mem(tmp);
   
   return *this;
   }
@@ -743,15 +757,24 @@ SpMat<eT>::operator*=(const SpMat<eT>& y)
 template<typename eT>
 inline
 SpMat<eT>&
-SpMat<eT>::operator%=(const SpMat<eT>& y)
+SpMat<eT>::operator%=(const SpMat<eT>& X)
   {
   arma_debug_sigprint();
   
   sync_csc();
   
-  SpMat<eT> z = (*this) % y;
-  
-  steal_mem(z);
+  if(X.n_nonzero == 0)
+    {
+    arma_conform_assert_same_size(n_rows, n_cols, X.n_rows, X.n_cols, "element-wise multiplication");
+    
+    (*this).zeros();
+    }
+  else
+    {
+    SpMat<eT> tmp = (*this) % X;
+    
+    steal_mem(tmp);
+    }
   
   return *this;
   }
@@ -1338,9 +1361,16 @@ SpMat<eT>::operator+=(const SpSubview<eT>& X)
   
   sync_csc();
   
-  SpMat<eT> tmp = (*this) + X;
-  
-  steal_mem(tmp);
+  if(X.n_nonzero == 0)
+    {
+    arma_conform_assert_same_size(n_rows, n_cols, X.n_rows, X.n_cols, "addition");
+    }
+  else
+    {
+    SpMat<eT> tmp = (*this) + X;
+    
+    steal_mem(tmp);
+    }
   
   return *this;
   }
@@ -1356,64 +1386,82 @@ SpMat<eT>::operator-=(const SpSubview<eT>& X)
   
   sync_csc();
   
-  SpMat<eT> tmp = (*this) - X;
-  
-  steal_mem(tmp);
-  
-  return *this;
-  }
-
-
-
-template<typename eT>
-inline
-SpMat<eT>&
-SpMat<eT>::operator*=(const SpSubview<eT>& y)
-  {
-  arma_debug_sigprint();
-  
-  sync_csc();
-  
-  SpMat<eT> z = (*this) * y;
-  
-  steal_mem(z);
-  
-  return *this;
-  }
-
-
-
-template<typename eT>
-inline
-SpMat<eT>&
-SpMat<eT>::operator%=(const SpSubview<eT>& x)
-  {
-  arma_debug_sigprint();
-  
-  sync_csc();
-  
-  SpMat<eT> tmp = (*this) % x;
-  
-  steal_mem(tmp);
-  
-  return *this;
-  }
-
-
-
-template<typename eT>
-inline
-SpMat<eT>&
-SpMat<eT>::operator/=(const SpSubview<eT>& x)
-  {
-  arma_debug_sigprint();
-  
-  arma_conform_assert_same_size(n_rows, n_cols, x.n_rows, x.n_cols, "element-wise division");
-  
-  // There is no pretty way to do this.
-  for(uword elem = 0; elem < n_elem; elem++)
+  if(X.n_nonzero == 0)
     {
-    at(elem) /= x(elem);
+    arma_conform_assert_same_size(n_rows, n_cols, X.n_rows, X.n_cols, "subtraction");
+    }
+  else
+    {
+    SpMat<eT> tmp = (*this) - X;
+    
+    steal_mem(tmp);
+    }
+  
+  return *this;
+  }
+
+
+
+template<typename eT>
+inline
+SpMat<eT>&
+SpMat<eT>::operator*=(const SpSubview<eT>& X)
+  {
+  arma_debug_sigprint();
+  
+  sync_csc();
+  
+  SpMat<eT> tmp = (*this) * X;
+  
+  steal_mem(tmp);
+  
+  return *this;
+  }
+
+
+
+template<typename eT>
+inline
+SpMat<eT>&
+SpMat<eT>::operator%=(const SpSubview<eT>& X)
+  {
+  arma_debug_sigprint();
+  
+  sync_csc();
+  
+  if(X.n_nonzero == 0)
+    {
+    arma_conform_assert_same_size(n_rows, n_cols, X.n_rows, X.n_cols, "element-wise multiplication");
+    
+    (*this).zeros();
+    }
+  else
+    {
+    SpMat<eT> tmp = (*this) % X;
+    
+    steal_mem(tmp);
+    }
+  
+  return *this;
+  }
+
+
+
+template<typename eT>
+inline
+SpMat<eT>&
+SpMat<eT>::operator/=(const SpSubview<eT>& X)
+  {
+  arma_debug_sigprint();
+  
+  // NOTE: use of this function is not advised; it is implemented only for completeness
+  
+  arma_conform_assert_same_size(n_rows, n_cols, X.n_rows, X.n_cols, "element-wise division");
+  
+  for(uword c = 0; c < n_cols; ++c)
+  for(uword r = 0; r < n_rows; ++r)
+    {
+    at(r, c) /= X.at(r, c);
     }
   
   return *this;
@@ -1507,9 +1555,9 @@ SpMat<eT>::operator*=(const SpSubview_col_list<eT,T1>& X)
   
   sync_csc();
   
-  SpMat<eT> z = (*this) * X;
+  SpMat<eT> tmp = (*this) * X;
   
-  steal_mem(z);
+  steal_mem(tmp);
   
   return *this;
   }

include/armadillo_bits/SpSubview_meat.hpp

@@ -44,6 +44,8 @@ SpSubview<eT>::SpSubview(const SpMat<eT>& in_m, const uword in_row1, const uword
   
   m.sync_csc();
   
+  if( (n_elem == 0) || (m.n_nonzero == 0) )  { return; }   // (*this).n_nonzero already set to zero
+  
   // count the number of non-zeros in the subview
   uword count = 0;
   
@@ -127,6 +129,8 @@ SpSubview<eT>::operator+=(const eT val)
   
   tmp.fill(val);
   
+  if(n_nonzero == 0)  { return (*this).operator=(tmp); }
+  
   return (*this).operator=( (*this) + tmp );
   }
 
@@ -319,6 +323,15 @@ SpSubview<eT>::operator+=(const Base<eT, T1>& x)
   {
   arma_debug_sigprint();
   
+  if(n_nonzero == 0)
+    {
+    const quasi_unwrap<T1> U(x.get_ref());
+    
+    arma_conform_assert_same_size(n_rows, n_cols, U.M.n_rows, U.M.n_cols, "addition");
+    
+    return (*this).operator=(U.M);
+    }
+  
   return (*this).operator=( (*this) + x.get_ref() );
   }
 
@@ -369,6 +382,8 @@ SpSubview<eT>::operator%=(const Base<eT, T1>& x)
   
   arma_conform_assert_same_size(sv.n_rows, sv.n_cols, B.n_rows, B.n_cols, "element-wise multiplication");
   
+  if(n_nonzero == 0)  { return *this; }
+  
   SpMat<eT>& sv_m = access::rw(sv.m);
   
   sv_m.sync_csc();
@@ -555,6 +570,15 @@ SpSubview<eT>::operator+=(const SpBase<eT, T1>& x)
   {
   arma_debug_sigprint();
   
+  if(n_nonzero == 0)
+    {
+    const unwrap_spmat<T1> U(x.get_ref());
+    
+    arma_conform_assert_same_size(n_rows, n_cols, U.M.n_rows, U.M.n_cols, "addition");
+    
+    return (*this).operator_equ_common(U.M);
+    }
+  
   // TODO: implement dedicated machinery
   return (*this).operator=( (*this) + x.get_ref() );
   }
@@ -596,6 +620,15 @@ SpSubview<eT>::operator%=(const SpBase<eT, T1>& x)
   {
   arma_debug_sigprint();
   
+  if(n_nonzero == 0)
+    {
+    const SpProxy<T1> P(x.get_ref());
+    
+    arma_conform_assert_same_size(n_rows, n_cols, P.get_n_rows(), P.get_n_cols(), "element-wise multiplication");
+    
+    return *this;
+    }
+  
   // TODO: implement dedicated machinery
   return (*this).operator=( (*this) % x.get_ref() );
   }
@@ -648,6 +681,8 @@ SpSubview<eT>::for_each(functor F)
   m.sync_csc();
   m.invalidate_cache();
   
+  if(n_nonzero == 0)  { return; }
+  
   const uword lstart_row = aux_row1;
   const uword lend_row   = aux_row1 + n_rows;
   
@@ -704,6 +739,8 @@ SpSubview<eT>::for_each(functor F) const
   
   m.sync_csc();
   
+  if(n_nonzero == 0)  { return; }
+  
   const uword lstart_row = aux_row1;
   const uword lend_row   = aux_row1 + n_rows;
   
@@ -743,6 +780,8 @@ SpSubview<eT>::transform(functor F)
   m.sync_csc();
   m.invalidate_cache();
   
+  if(n_nonzero == 0)  { return; }
+  
   const uword lstart_row = aux_row1;
   const uword lend_row   = aux_row1 + n_rows;
   
@@ -813,6 +852,8 @@ SpSubview<eT>::replace(const eT old_val, const eT new_val)
   m.sync_csc();
   m.invalidate_cache();
   
+  if(n_nonzero == 0)  { return; }
+  
   const uword lstart_row = aux_row1;
   const uword lend_row   = aux_row1 + n_rows;
   

include/armadillo_bits/arma_version.hpp

@@ -23,7 +23,7 @@
 
 #define ARMA_VERSION_MAJOR 15
 #define ARMA_VERSION_MINOR 2
-#define ARMA_VERSION_PATCH 2
+#define ARMA_VERSION_PATCH 4
 #define ARMA_VERSION_NAME  "Medium Roast Deluxe"
 
 

include/armadillo_bits/config.hpp

@@ -330,18 +330,6 @@
   #undef ARMA_OPTIMISE_POWEXPR
 #endif
 
-#if defined(ARMA_DONT_CHECK_CONFORMANCE)
-  #if defined(ARMA_CHECK_CONFORMANCE) && (ARMA_WARN_LEVEL >= 2)
-    #pragma message ("WARNING: conformance checks disabled")
-  #endif
-  
-  #undef ARMA_CHECK_CONFORMANCE
-#endif
-
-#if defined(ARMA_DONT_CHECK_NONFINITE)
-  #undef ARMA_CHECK_NONFINITE
-#endif
-
 #if defined(ARMA_NO_DEBUG)
   #undef ARMA_DEBUG
   #undef ARMA_EXTRA_DEBUG
@@ -361,6 +349,18 @@
   #define ARMA_WARN_LEVEL 3
 #endif
 
+#if defined(ARMA_DONT_CHECK_CONFORMANCE)
+  #if defined(ARMA_CHECK_CONFORMANCE) && (ARMA_WARN_LEVEL >= 2)
+    #pragma message ("WARNING: conformance checks disabled")
+  #endif
+  
+  #undef ARMA_CHECK_CONFORMANCE
+#endif
+
+#if defined(ARMA_DONT_CHECK_NONFINITE)
+  #undef ARMA_CHECK_NONFINITE
+#endif
+
 #if defined(ARMA_DONT_PRINT_EXCEPTIONS)
   #undef ARMA_PRINT_EXCEPTIONS
 #endif

include/armadillo_bits/config.hpp.cmake

@@ -330,18 +330,6 @@
   #undef ARMA_OPTIMISE_POWEXPR
 #endif
 
-#if defined(ARMA_DONT_CHECK_CONFORMANCE)
-  #if defined(ARMA_CHECK_CONFORMANCE) && (ARMA_WARN_LEVEL >= 2)
-    #pragma message ("WARNING: conformance checks disabled")
-  #endif
-  
-  #undef ARMA_CHECK_CONFORMANCE
-#endif
-
-#if defined(ARMA_DONT_CHECK_NONFINITE)
-  #undef ARMA_CHECK_NONFINITE
-#endif
-
 #if defined(ARMA_NO_DEBUG)
   #undef ARMA_DEBUG
   #undef ARMA_EXTRA_DEBUG
@@ -361,6 +349,18 @@
   #define ARMA_WARN_LEVEL 3
 #endif
 
+#if defined(ARMA_DONT_CHECK_CONFORMANCE)
+  #if defined(ARMA_CHECK_CONFORMANCE) && (ARMA_WARN_LEVEL >= 2)
+    #pragma message ("WARNING: conformance checks disabled")
+  #endif
+  
+  #undef ARMA_CHECK_CONFORMANCE
+#endif
+
+#if defined(ARMA_DONT_CHECK_NONFINITE)
+  #undef ARMA_CHECK_NONFINITE
+#endif
+
 #if defined(ARMA_DONT_PRINT_EXCEPTIONS)
   #undef ARMA_PRINT_EXCEPTIONS
 #endif

include/armadillo_bits/constants.hpp

@@ -62,11 +62,14 @@ namespace priv
       }
     
     
+    //
+    
+    
     template<typename eT>
     static
     constexpr
     typename arma_real_only<eT>::result
-    inf(typename arma_real_only<eT>::result* junk = nullptr)
+    pos_inf(typename arma_real_only<eT>::result* junk = nullptr)
       {
       arma_ignore(junk);
       
@@ -78,13 +81,13 @@ namespace priv
     static
     constexpr
     typename arma_cx_only<eT>::result
-    inf(typename arma_cx_only<eT>::result* junk = nullptr)
+    pos_inf(typename arma_cx_only<eT>::result* junk = nullptr)
       {
       arma_ignore(junk);
       
       typedef typename get_pod_type<eT>::result T;
       
-      return eT( Datum_helper::inf<T>(), Datum_helper::inf<T>() );
+      return eT( Datum_helper::pos_inf<T>(), Datum_helper::pos_inf<T>() );
       }
     
     
@@ -92,12 +95,54 @@ namespace priv
     static
     constexpr
     typename arma_integral_only<eT>::result
-    inf(typename arma_integral_only<eT>::result* junk = nullptr)
+    pos_inf(typename arma_integral_only<eT>::result* junk = nullptr)
       {
       arma_ignore(junk);
       
       return std::numeric_limits<eT>::max();
       }
+    
+    
+    //
+    
+    
+    template<typename eT>
+    static
+    constexpr
+    typename arma_real_only<eT>::result
+    neg_inf(typename arma_real_only<eT>::result* junk = nullptr)
+      {
+      arma_ignore(junk);
+      
+      return (std::numeric_limits<eT>::has_infinity) ? eT(-std::numeric_limits<eT>::infinity()) : eT(std::numeric_limits<eT>::lowest());
+      }
+    
+    
+    template<typename eT>
+    static
+    constexpr
+    typename arma_cx_only<eT>::result
+    neg_inf(typename arma_cx_only<eT>::result* junk = nullptr)
+      {
+      arma_ignore(junk);
+      
+      typedef typename get_pod_type<eT>::result T;
+      
+      return eT( Datum_helper::neg_inf<T>(), Datum_helper::neg_inf<T>() );
+      }
+    
+    
+    template<typename eT>
+    static
+    constexpr
+    typename arma_integral_only<eT>::result
+    neg_inf(typename arma_integral_only<eT>::result* junk = nullptr)
+      {
+      arma_ignore(junk);
+      
+      return std::numeric_limits<eT>::lowest();
+      }
+    
     };
   }
 
@@ -125,7 +170,9 @@ struct Datum
   static const eT log_min;      //!< log of the minimum representable value
   static const eT log_max;      //!< log of the maximum representable value
   static const eT nan;          //!< "not a number"
-  static const eT inf;          //!< infinity 
+  static const eT inf;          //!< positive infinity
+  static const eT pos_inf;      //!< positive infinity
+  static const eT neg_inf;      //!< negative infinity
 
   // 
   
@@ -176,7 +223,9 @@ template<typename eT> const eT Datum<eT>::eps         = std::numeric_limits<eT>:
 template<typename eT> const eT Datum<eT>::log_min     = std::log(std::numeric_limits<eT>::min());
 template<typename eT> const eT Datum<eT>::log_max     = std::log(std::numeric_limits<eT>::max());
 template<typename eT> const eT Datum<eT>::nan         = priv::Datum_helper::nan<eT>();
-template<typename eT> const eT Datum<eT>::inf         = priv::Datum_helper::inf<eT>();
+template<typename eT> const eT Datum<eT>::inf         = priv::Datum_helper::pos_inf<eT>();
+template<typename eT> const eT Datum<eT>::pos_inf     = priv::Datum_helper::pos_inf<eT>();
+template<typename eT> const eT Datum<eT>::neg_inf     = priv::Datum_helper::neg_inf<eT>();
 
 template<typename eT> const eT Datum<eT>::m_u       = eT(1.66053906892e-27);
 template<typename eT> const eT Datum<eT>::N_A       = eT(6.02214076e23);

include/armadillo_bits/fill.hpp

@@ -22,22 +22,29 @@
 
 namespace fill
   {
-  struct fill_none  {};
-  struct fill_zeros {};
-  struct fill_ones  {};
-  struct fill_eye   {};
-  struct fill_randu {};
-  struct fill_randn {};
+  struct fill_none    {};
+  struct fill_zeros   {};
+  struct fill_ones    {};
+  struct fill_eye     {};
+  struct fill_randu   {};
+  struct fill_randn   {};
+  struct fill_nan     {};
+  struct fill_pos_inf {};
+  struct fill_neg_inf {};
   
   template<typename fill_type> 
   struct fill_class { inline constexpr fill_class() {} };
   
-  static constexpr fill_class<fill_none > none;
-  static constexpr fill_class<fill_zeros> zeros;
-  static constexpr fill_class<fill_ones > ones;
-  static constexpr fill_class<fill_eye  > eye;
-  static constexpr fill_class<fill_randu> randu;
-  static constexpr fill_class<fill_randn> randn;
+  static constexpr fill_class<fill_none   > none;
+  static constexpr fill_class<fill_zeros  > zeros;
+  static constexpr fill_class<fill_ones   > ones;
+  static constexpr fill_class<fill_eye    > eye;
+  static constexpr fill_class<fill_randu  > randu;
+  static constexpr fill_class<fill_randn  > randn;
+  static constexpr fill_class<fill_nan    > nan;
+  static constexpr fill_class<fill_pos_inf> inf;
+  static constexpr fill_class<fill_pos_inf> pos_inf;
+  static constexpr fill_class<fill_neg_inf> neg_inf;
   
   //
   

include/armadillo_bits/op_accu_meat.hpp

@@ -80,6 +80,8 @@ op_accu_mat::apply_proxy_at(const Proxy<T1>& P)
   const uword n_rows = P.get_n_rows();
   const uword n_cols = P.get_n_cols();
   
+  if(n_rows == 0)  { return eT(0); }
+  
   eT val = eT(0);
   
   if(n_rows != 1)
@@ -146,6 +148,8 @@ op_accu_mat::apply_omit_helper(const Proxy<T1>& P, functor is_omitted)
     const uword n_rows = P.get_n_rows();
     const uword n_cols = P.get_n_cols();
     
+    if(n_rows == 0)  { return eT_zero; }
+    
     for(uword c=0; c < n_cols; ++c)
     for(uword r=0; r < n_rows; ++r)
       {
@@ -602,6 +606,8 @@ op_accu_mat::apply(const subview<eT>& X)
   const uword X_n_rows = X.n_rows;
   const uword X_n_cols = X.n_cols;
   
+  if( (X_n_rows == 0) || (X_n_cols == 0) )  { return eT(0); }
+  
   if(X_n_rows == 1)
     {
     const uword X_m_n_rows = X.m.n_rows;
@@ -750,6 +756,8 @@ op_accu_cube::apply_proxy_at(const ProxyCube<T1>& P)
   const uword n_cols   = P.get_n_cols();
   const uword n_slices = P.get_n_slices();
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return eT(0); }
+  
   eT val1 = eT(0);
   eT val2 = eT(0);
   

include/armadillo_bits/op_htrans_meat.hpp

@@ -65,6 +65,7 @@ op_htrans::apply_mat_noalias(Mat<eT>& out, const Mat<eT>& A, const typename arma
     op_htrans::apply_mat_noalias_large(out, A);
     }
   else
+  if( (A_n_rows != 0) && (A_n_cols != 0) )
     {
     eT* outptr = out.memptr();
     

include/armadillo_bits/op_repmat_meat.hpp

@@ -153,15 +153,19 @@ op_repcube::apply_noalias(Cube<eT>& out, const Cube<eT>& X, const uword copies_p
   
   if(out.is_empty())  { return; }
   
-  // TODO: this is a rudimentary implementation
-  
-  const SizeCube X_size = SizeCube(X.n_rows, X.n_cols, X.n_slices);
-  
-  for(uword s = 0; s < out.n_slices; s += X.n_slices)
-  for(uword c = 0; c < out.n_cols;   c += X.n_cols  )
-  for(uword r = 0; r < out.n_rows;   r += X.n_rows  )
+  for(uword s=0; s < X.n_slices; ++s)
     {
-    out.subcube(r, c, s, X_size) = X;
+    // avoid use of Cube::slice() to prevent generating Mat objects that the user may not need
+    
+    const Mat<eT>   X_slice_s(const_cast<eT*>(X.slice_memptr(s)),   X.n_rows,   X.n_cols, false, true);
+          Mat<eT> out_slice_s(              out.slice_memptr(s) , out.n_rows, out.n_cols, false, true);
+    
+    op_repmat::apply_noalias(out_slice_s, X_slice_s, copies_per_row, copies_per_col);
+    
+    for(uword t=1; t < copies_per_slice; ++t)
+      {
+      arrayops::copy(out.slice_memptr(s + (t * X.n_slices)), out_slice_s.memptr(), out_slice_s.n_elem);
+      }
     }
   }
 

include/armadillo_bits/op_resize_meat.hpp

@@ -81,7 +81,7 @@ op_resize::apply_mat_inplace(Mat<eT>& A, const uword new_n_rows, const uword new
   arma_conform_check( (A.vec_state == 1) && (new_n_cols != 1), "resize(): requested size is not compatible with column vector layout" );
   arma_conform_check( (A.vec_state == 2) && (new_n_rows != 1), "resize(): requested size is not compatible with row vector layout"    );
   
-  if(A.is_empty())  { A.zeros(new_n_rows, new_n_cols); return; }
+  if( A.is_empty() || (new_n_rows == 0) || (new_n_cols == 0) )  { A.zeros(new_n_rows, new_n_cols); return; }
   
   Mat<eT> B(new_n_rows, new_n_cols, arma_nozeros_indicator());
   

include/armadillo_bits/op_strans_meat.hpp

@@ -200,6 +200,7 @@ op_strans::apply_mat_noalias(Mat<eT>& out, const TA& A)
       op_strans::apply_mat_noalias_large(out, A);
       }
     else
+    if( (A_n_rows != 0) && (A_n_cols != 0) )
       {
       eT* outptr = out.memptr();
       

include/armadillo_bits/op_vectorise_meat.hpp

@@ -176,6 +176,8 @@ op_vectorise_col::apply_subview(Mat<eT>& out, const subview<eT>& sv)
   
   out.set_size(sv.n_elem, 1);
   
+  if(sv.n_elem == 0)  { return; }
+  
   eT* out_mem = out.memptr();
   
   for(uword col=0; col < sv_n_cols; ++col)
@@ -201,6 +203,8 @@ op_vectorise_col::apply_proxy(Mat<typename T1::elem_type>& out, const Proxy<T1>&
   
   out.set_size(N, 1);
   
+  if(N == 0)  { return; }
+  
   eT* outmem = out.memptr();
   
   if(Proxy<T1>::use_at == false)
@@ -305,6 +309,8 @@ op_vectorise_row::apply_proxy(Mat<typename T1::elem_type>& out, const Proxy<T1>&
   
   out.set_size(1, n_elem);
   
+  if(n_elem == 0)  { return; }
+  
   eT* outmem = out.memptr();
   
   if(n_cols == 1)
@@ -471,6 +477,8 @@ op_vectorise_cube_col::apply_proxy(Mat<typename T1::elem_type>& out, const T1& e
   
   out.set_size(N, 1);
   
+  if(N == 0)  { return; }
+  
   eT* outmem = out.memptr();
   
   if(ProxyCube<T1>::use_at == false)

include/armadillo_bits/subview_bones.hpp

@@ -142,6 +142,9 @@ class subview : public Base< eT, subview<eT> >
   arma_inline       eT* colptr(const uword in_col);
   arma_inline const eT* colptr(const uword in_col) const;
   
+  arma_inline       eT* startptr();
+  arma_inline const eT* startptr() const;
+  
   template<typename eT2>
   inline bool check_overlap(const subview<eT2>& x) const;
   

include/armadillo_bits/subview_cube_each_meat.hpp

@@ -109,6 +109,8 @@ subview_cube_each1<eT>::operator= (const Base<eT,T1>& in)
   const uword p_n_slices     = p.n_slices;
   const uword p_n_elem_slice = p.n_elem_slice;
   
+  if(p_n_elem_slice == 0)  { return; }
+  
   const eT* A_mem = A.memptr();
   
   for(uword i=0; i < p_n_slices; ++i)  { arrayops::copy( p.slice_memptr(i), A_mem, p_n_elem_slice ); }
@@ -134,6 +136,8 @@ subview_cube_each1<eT>::operator+= (const Base<eT,T1>& in)
   const uword p_n_slices     = p.n_slices;
   const uword p_n_elem_slice = p.n_elem_slice;
   
+  if(p_n_elem_slice == 0)  { return; }
+  
   const eT* A_mem = A.memptr();
   
   for(uword i=0; i < p_n_slices; ++i)  { arrayops::inplace_plus( p.slice_memptr(i), A_mem, p_n_elem_slice ); }
@@ -159,6 +163,8 @@ subview_cube_each1<eT>::operator-= (const Base<eT,T1>& in)
   const uword p_n_slices     = p.n_slices;
   const uword p_n_elem_slice = p.n_elem_slice;
   
+  if(p_n_elem_slice == 0)  { return; }
+  
   const eT* A_mem = A.memptr();
   
   for(uword i=0; i < p_n_slices; ++i)  { arrayops::inplace_minus( p.slice_memptr(i), A_mem, p_n_elem_slice ); }
@@ -184,6 +190,8 @@ subview_cube_each1<eT>::operator%= (const Base<eT,T1>& in)
   const uword p_n_slices     = p.n_slices;
   const uword p_n_elem_slice = p.n_elem_slice;
   
+  if(p_n_elem_slice == 0)  { return; }
+  
   const eT* A_mem = A.memptr();
   
   for(uword i=0; i < p_n_slices; ++i)  { arrayops::inplace_mul( p.slice_memptr(i), A_mem, p_n_elem_slice ); }
@@ -209,6 +217,8 @@ subview_cube_each1<eT>::operator/= (const Base<eT,T1>& in)
   const uword p_n_slices     = p.n_slices;
   const uword p_n_elem_slice = p.n_elem_slice;
   
+  if(p_n_elem_slice == 0)  { return; }
+  
   const eT* A_mem = A.memptr();
   
   for(uword i=0; i < p_n_slices; ++i)  { arrayops::inplace_div( p.slice_memptr(i), A_mem, p_n_elem_slice ); }
@@ -300,6 +310,8 @@ subview_cube_each2<eT,TB>::operator= (const Base<eT,T1>& in)
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if(p_n_elem_slice == 0)  { continue; }
+    
     arrayops::copy(p.slice_memptr(slice), A_mem, p_n_elem_slice);
     }
   }
@@ -339,6 +351,8 @@ subview_cube_each2<eT,TB>::operator+= (const Base<eT,T1>& in)
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if(p_n_elem_slice == 0)  { continue; }
+    
     arrayops::inplace_plus(p.slice_memptr(slice), A_mem, p_n_elem_slice);
     }
   }
@@ -378,6 +392,8 @@ subview_cube_each2<eT,TB>::operator-= (const Base<eT,T1>& in)
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if(p_n_elem_slice == 0)  { continue; }
+    
     arrayops::inplace_minus(p.slice_memptr(slice), A_mem, p_n_elem_slice);
     }
   }
@@ -417,6 +433,8 @@ subview_cube_each2<eT,TB>::operator%= (const Base<eT,T1>& in)
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if(p_n_elem_slice == 0)  { continue; }
+    
     arrayops::inplace_mul(p.slice_memptr(slice), A_mem, p_n_elem_slice);
     }
   }
@@ -456,6 +474,8 @@ subview_cube_each2<eT,TB>::operator/= (const Base<eT,T1>& in)
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if(p_n_elem_slice == 0)  { continue; }
+    
     arrayops::inplace_div(p.slice_memptr(slice), A_mem, p_n_elem_slice);
     }
   }
@@ -492,12 +512,15 @@ subview_cube_each1_aux::operator_plus
   
   X.check_size(A);
   
-  for(uword i=0; i < p_n_slices; ++i)
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-          Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
-    const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
-    
-    out_slice = p_slice + A;
+    for(uword i=0; i < p_n_slices; ++i)
+      {
+            Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
+      const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
+      
+      out_slice = p_slice + A;
+      }
     }
   
   return out;
@@ -529,12 +552,15 @@ subview_cube_each1_aux::operator_minus
   
   X.check_size(A);
   
-  for(uword i=0; i < p_n_slices; ++i)
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-          Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
-    const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
-    
-    out_slice = p_slice - A;
+    for(uword i=0; i < p_n_slices; ++i)
+      {
+            Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
+      const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
+      
+      out_slice = p_slice - A;
+      }
     }
   
   return out;
@@ -566,12 +592,15 @@ subview_cube_each1_aux::operator_minus
   
   Y.check_size(A);
   
-  for(uword i=0; i < p_n_slices; ++i)
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-          Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
-    const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
-    
-    out_slice = A - p_slice;
+    for(uword i=0; i < p_n_slices; ++i)
+      {
+            Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
+      const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
+      
+      out_slice = A - p_slice;
+      }
     }
   
   return out;
@@ -603,12 +632,15 @@ subview_cube_each1_aux::operator_schur
   
   X.check_size(A);
   
-  for(uword i=0; i < p_n_slices; ++i)
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-          Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
-    const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
-    
-    out_slice = p_slice % A;
+    for(uword i=0; i < p_n_slices; ++i)
+      {
+            Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
+      const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
+      
+      out_slice = p_slice % A;
+      }
     }
   
   return out;
@@ -640,12 +672,15 @@ subview_cube_each1_aux::operator_div
   
   X.check_size(A);
   
-  for(uword i=0; i < p_n_slices; ++i)
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-          Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
-    const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
-    
-    out_slice = p_slice / A;
+    for(uword i=0; i < p_n_slices; ++i)
+      {
+            Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
+      const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
+      
+      out_slice = p_slice / A;
+      }
     }
   
   return out;
@@ -677,12 +712,15 @@ subview_cube_each1_aux::operator_div
   
   Y.check_size(A);
   
-  for(uword i=0; i < p_n_slices; ++i)
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-          Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
-    const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
-    
-    out_slice = A / p_slice;
+    for(uword i=0; i < p_n_slices; ++i)
+      {
+            Mat<eT> out_slice(              out.slice_memptr(i),  p_n_rows, p_n_cols, false, true);
+      const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(i)), p_n_rows, p_n_cols, false, true);
+      
+      out_slice = A / p_slice;
+      }
     }
   
   return out;
@@ -706,14 +744,26 @@ subview_cube_each1_aux::operator_times
   const unwrap<T2>   tmp(Y.get_ref());
   const Mat<eT>& M = tmp.M;
   
+  if(arma_config::check_conform)
+    {
+    if(C.n_cols != M.n_rows)  { arma_stop_logic_error("each_slice(): incompatible sizes for matrix multiplication"); }
+    }
+  
   Cube<eT> out(C.n_rows, M.n_cols, C.n_slices, arma_nozeros_indicator());
   
-  for(uword i=0; i < C.n_slices; ++i)
+  if( (C.n_elem == 0) || (M.n_elem == 0) )
     {
-          Mat<eT> out_slice(              out.slice_memptr(i),  C.n_rows, M.n_cols, false, true);
-    const Mat<eT>   C_slice(const_cast<eT*>(C.slice_memptr(i)), C.n_rows, C.n_cols, false, true);
-    
-    out_slice = C_slice * M;
+    out.zeros();
+    }
+  else
+    {
+    for(uword i=0; i < C.n_slices; ++i)
+      {
+            Mat<eT> out_slice(              out.slice_memptr(i),  C.n_rows, M.n_cols, false, true);
+      const Mat<eT>   C_slice(const_cast<eT*>(C.slice_memptr(i)), C.n_rows, C.n_cols, false, true);
+      
+      out_slice = C_slice * M;
+      }
     }
   
   return out;
@@ -737,14 +787,26 @@ subview_cube_each1_aux::operator_times
   
   const Cube<eT>& C = Y.P;
   
+  if(arma_config::check_conform)
+    {
+    if(M.n_cols != C.n_rows)  { arma_stop_logic_error("each_slice(): incompatible sizes for matrix multiplication"); }
+    }
+  
   Cube<eT> out(M.n_rows, C.n_cols, C.n_slices, arma_nozeros_indicator());
   
-  for(uword i=0; i < C.n_slices; ++i)
+  if( (M.n_elem == 0) || (C.n_elem == 0) )
     {
-          Mat<eT> out_slice(              out.slice_memptr(i),  M.n_rows, C.n_cols, false, true);
-    const Mat<eT>   C_slice(const_cast<eT*>(C.slice_memptr(i)), C.n_rows, C.n_cols, false, true);
-    
-    out_slice = M * C_slice;
+    out.zeros();
+    }
+  else
+    {
+    for(uword i=0; i < C.n_slices; ++i)
+      {
+            Mat<eT> out_slice(              out.slice_memptr(i),  M.n_rows, C.n_cols, false, true);
+      const Mat<eT>   C_slice(const_cast<eT*>(C.slice_memptr(i)), C.n_rows, C.n_cols, false, true);
+      
+      out_slice = M * C_slice;
+      }
     }
   
   return out;
@@ -795,6 +857,8 @@ subview_cube_each2_aux::operator_plus
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if(p_n_elem_slice == 0)  { continue; }
+    
     arrayops::inplace_plus(out.slice_memptr(slice), A_mem, p_n_elem_slice);
     }
   
@@ -840,6 +904,8 @@ subview_cube_each2_aux::operator_minus
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if(p_n_elem_slice == 0)  { continue; }
+    
     arrayops::inplace_minus(out.slice_memptr(slice), A_mem, p_n_elem_slice);
     }
   
@@ -884,6 +950,8 @@ subview_cube_each2_aux::operator_minus
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if( (p_n_rows == 0) || (p_n_cols == 0) )  { continue; }
+    
           Mat<eT> out_slice(              out.slice_memptr(slice),  p_n_rows, p_n_cols, false, true);
     const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(slice)), p_n_rows, p_n_cols, false, true);
     
@@ -932,6 +1000,8 @@ subview_cube_each2_aux::operator_schur
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if(p_n_elem_slice == 0)  { continue; }
+    
     arrayops::inplace_mul(out.slice_memptr(slice), A_mem, p_n_elem_slice);
     }
   
@@ -977,6 +1047,8 @@ subview_cube_each2_aux::operator_div
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if(p_n_elem_slice == 0)  { continue; }
+    
     arrayops::inplace_div(out.slice_memptr(slice), A_mem, p_n_elem_slice);
     }
   
@@ -1021,6 +1093,8 @@ subview_cube_each2_aux::operator_div
     
     arma_conform_check_bounds( (slice >= p_n_slices), "each_slice(): index out of bounds" );
     
+    if( (p_n_rows == 0) || (p_n_cols == 0) )  { continue; }
+    
           Mat<eT> out_slice(              out.slice_memptr(slice),  p_n_rows, p_n_cols, false, true);
     const Mat<eT>   p_slice(const_cast<eT*>(p.slice_memptr(slice)), p_n_rows, p_n_cols, false, true);
     

include/armadillo_bits/subview_cube_meat.hpp

@@ -117,6 +117,8 @@ subview_cube<eT>::inplace_op(const eT val)
   const uword t_n_cols   = t.n_cols;
   const uword t_n_slices = t.n_slices;
   
+  if( (t_n_rows == 0) || (t_n_cols == 0) )  { return; }
+  
   for(uword s=0; s < t_n_slices; ++s)
   for(uword c=0; c < t_n_cols;   ++c)
     {
@@ -150,6 +152,8 @@ subview_cube<eT>::inplace_op(const BaseCube<eT,T1>& in, const char* identifier)
   
   arma_conform_assert_same_size(t, P, identifier);
   
+  if( (t_n_rows == 0) || (t_n_cols == 0) || (t_n_slices == 0) )  { return; }
+  
   const bool use_mp      = arma_config::openmp && ProxyCube<T1>::use_mp && mp_gate<eT>::eval(t.n_elem);
   const bool has_overlap = P.has_overlap(t);
   
@@ -258,6 +262,8 @@ subview_cube<eT>::inplace_op(const subview_cube<eT>& x, const char* identifier)
   const uword t_n_cols   = t.n_cols;
   const uword t_n_slices = t.n_slices;
   
+  if( (t_n_rows == 0) || (t_n_cols == 0) )  { return; }
+  
   for(uword s=0; s < t_n_slices; ++s)
   for(uword c=0; c < t_n_cols;   ++c)
     {
@@ -1174,6 +1180,8 @@ subview_cube<eT>::replace(const eT old_val, const eT new_val)
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
+  if( (local_n_rows == 0) || (local_n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice < local_n_slices; ++slice)
     {
     for(uword col = 0; col < local_n_cols; ++col)
@@ -1196,6 +1204,8 @@ subview_cube<eT>::clean(const typename get_pod_type<eT>::result threshold)
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
+  if( (local_n_rows == 0) || (local_n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice < local_n_slices; ++slice)
     {
     for(uword col = 0; col < local_n_cols; ++col)
@@ -1228,6 +1238,8 @@ subview_cube<eT>::clamp(const eT min_val, const eT max_val)
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
+  if( (local_n_rows == 0) || (local_n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice < local_n_slices; ++slice)
     {
     for(uword col = 0; col < local_n_cols; ++col)
@@ -1250,6 +1262,8 @@ subview_cube<eT>::fill(const eT val)
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
+  if( (local_n_rows == 0) || (local_n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice < local_n_slices; ++slice)
     {
     for(uword col = 0; col < local_n_cols; ++col)
@@ -1272,6 +1286,8 @@ subview_cube<eT>::zeros()
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
+  if( (local_n_rows == 0) || (local_n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice < local_n_slices; ++slice)
     {
     for(uword col = 0; col < local_n_cols; ++col)
@@ -1306,6 +1322,8 @@ subview_cube<eT>::randu()
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
+  if( (local_n_rows == 0) || (local_n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice < local_n_slices; ++slice)
     {
     for(uword col = 0; col < local_n_cols; ++col)
@@ -1328,6 +1346,8 @@ subview_cube<eT>::randn()
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
+  if( (local_n_rows == 0) || (local_n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice < local_n_slices; ++slice)
     {
     for(uword col = 0; col < local_n_cols; ++col)
@@ -1352,11 +1372,14 @@ subview_cube<eT>::is_finite() const
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
-  for(uword slice = 0; slice < local_n_slices; ++slice)
+  if( (local_n_rows != 0) && (local_n_cols != 0) )
     {
-    for(uword col = 0; col < local_n_cols; ++col)
+    for(uword slice = 0; slice < local_n_slices; ++slice)
       {
-      if(arrayops::is_finite(slice_colptr(slice,col), local_n_rows) == false)  { return false; }
+      for(uword col = 0; col < local_n_cols; ++col)
+        {
+        if(arrayops::is_finite(slice_colptr(slice,col), local_n_rows) == false)  { return false; }
+        }
       }
     }
   
@@ -1376,11 +1399,14 @@ subview_cube<eT>::is_zero(const typename get_pod_type<eT>::result tol) const
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
-  for(uword slice = 0; slice < local_n_slices; ++slice)
+  if( (local_n_rows != 0) && (local_n_cols != 0) )
     {
-    for(uword col = 0; col < local_n_cols; ++col)
+    for(uword slice = 0; slice < local_n_slices; ++slice)
       {
-      if(arrayops::is_zero(slice_colptr(slice,col), local_n_rows, tol) == false)  { return false; }
+      for(uword col = 0; col < local_n_cols; ++col)
+        {
+        if(arrayops::is_zero(slice_colptr(slice,col), local_n_rows, tol) == false)  { return false; }
+        }
       }
     }
   
@@ -1402,11 +1428,14 @@ subview_cube<eT>::has_inf() const
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
-  for(uword slice = 0; slice < local_n_slices; ++slice)
+  if( (local_n_rows != 0) && (local_n_cols != 0) )
     {
-    for(uword col = 0; col < local_n_cols; ++col)
+    for(uword slice = 0; slice < local_n_slices; ++slice)
       {
-      if(arrayops::has_inf(slice_colptr(slice,col), local_n_rows))  { return true; }
+      for(uword col = 0; col < local_n_cols; ++col)
+        {
+        if(arrayops::has_inf(slice_colptr(slice,col), local_n_rows))  { return true; }
+        }
       }
     }
   
@@ -1428,11 +1457,14 @@ subview_cube<eT>::has_nan() const
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
-  for(uword slice = 0; slice < local_n_slices; ++slice)
+  if( (local_n_rows != 0) && (local_n_cols != 0) )
     {
-    for(uword col = 0; col < local_n_cols; ++col)
+    for(uword slice = 0; slice < local_n_slices; ++slice)
       {
-      if(arrayops::has_nan(slice_colptr(slice,col), local_n_rows))  { return true; }
+      for(uword col = 0; col < local_n_cols; ++col)
+        {
+        if(arrayops::has_nan(slice_colptr(slice,col), local_n_rows))  { return true; }
+        }
       }
     }
   
@@ -1454,11 +1486,14 @@ subview_cube<eT>::has_nonfinite() const
   const uword local_n_cols   = n_cols;
   const uword local_n_slices = n_slices;
   
-  for(uword slice = 0; slice < local_n_slices; ++slice)
+  if( (local_n_rows != 0) && (local_n_cols != 0) )
     {
-    for(uword col = 0; col < local_n_cols; ++col)
+    for(uword slice = 0; slice < local_n_slices; ++slice)
       {
-      if(arrayops::is_finite(slice_colptr(slice,col), local_n_rows) == false)  { return true; }
+      for(uword col = 0; col < local_n_cols; ++col)
+        {
+        if(arrayops::is_finite(slice_colptr(slice,col), local_n_rows) == false)  { return true; }
+        }
       }
     }
   
@@ -1614,7 +1649,7 @@ arma_inline
 eT*
 subview_cube<eT>::slice_colptr(const uword in_slice, const uword in_col)
   {
-  return & access::rw((const_cast< Cube<eT>& >(m)).mem[  (in_slice + aux_slice1)*m.n_elem_slice + (in_col + aux_col1)*m.n_rows + aux_row1  ]);
+  return access::rwp( m.mem + ( (in_slice + aux_slice1)*m.n_elem_slice + (in_col + aux_col1)*m.n_rows + aux_row1 ) );
   }
 
 
@@ -1624,7 +1659,7 @@ arma_inline
 const eT*
 subview_cube<eT>::slice_colptr(const uword in_slice, const uword in_col) const
   {
-  return & m.mem[ (in_slice + aux_slice1)*m.n_elem_slice + (in_col + aux_col1)*m.n_rows + aux_row1 ];
+  return m.mem + ( (in_slice + aux_slice1)*m.n_elem_slice + (in_col + aux_col1)*m.n_rows + aux_row1 );
   }
 
 
@@ -1704,7 +1739,7 @@ void
 subview_cube<eT>::extract(Cube<eT>& out, const subview_cube<eT>& in)
   {
   arma_debug_sigprint();
-
+  
   // NOTE: we're assuming that the cube has already been set to the correct size and there is no aliasing;
   // size setting and alias checking is done by either the Cube constructor or operator=()
   
@@ -1714,6 +1749,8 @@ subview_cube<eT>::extract(Cube<eT>& out, const subview_cube<eT>& in)
   
   arma_debug_print(arma_str::format("out.n_rows: %u; out.n_cols: %u; out.n_slices: %u; in.m.n_rows: %u; in.m.n_cols: %u; in.m.n_slices: %u") % out.n_rows % out.n_cols % out.n_slices % in.m.n_rows % in.m.n_cols % in.m.n_slices);
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
   if( (in.aux_row1 == 0) && (n_rows == in.m.n_rows) )
     {
     for(uword s=0; s < n_slices; ++s)
@@ -1747,6 +1784,8 @@ subview_cube<eT>::plus_inplace(Cube<eT>& out, const subview_cube<eT>& in)
   const uword n_cols   = out.n_cols;
   const uword n_slices = out.n_slices;
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice<n_slices; ++slice)
     {
     for(uword col = 0; col<n_cols; ++col)
@@ -1772,6 +1811,8 @@ subview_cube<eT>::minus_inplace(Cube<eT>& out, const subview_cube<eT>& in)
   const uword n_cols   = out.n_cols;
   const uword n_slices = out.n_slices;
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice<n_slices; ++slice)
     {
     for(uword col = 0; col<n_cols; ++col)
@@ -1797,6 +1838,8 @@ subview_cube<eT>::schur_inplace(Cube<eT>& out, const subview_cube<eT>& in)
   const uword n_cols   = out.n_cols;
   const uword n_slices = out.n_slices;
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice<n_slices; ++slice)
     {
     for(uword col = 0; col<n_cols; ++col)
@@ -1822,6 +1865,8 @@ subview_cube<eT>::div_inplace(Cube<eT>& out, const subview_cube<eT>& in)
   const uword n_cols   = out.n_cols;
   const uword n_slices = out.n_slices;
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
   for(uword slice = 0; slice<n_slices; ++slice)
     {
     for(uword col = 0; col<n_cols; ++col)

include/armadillo_bits/subview_each_meat.hpp

@@ -157,6 +157,8 @@ subview_each1<parent,mode>::operator= (const Base<eT,T1>& in)
   const uword p_n_rows = p.n_rows;
   const uword p_n_cols = p.n_cols;
   
+  if(p_n_rows == 0)  { return; }
+  
   if(mode == 0) // each column
     {
     for(uword i=0; i < p_n_cols; ++i)
@@ -194,6 +196,8 @@ subview_each1<parent,mode>::operator+= (const Base<eT,T1>& in)
   const uword p_n_rows = p.n_rows;
   const uword p_n_cols = p.n_cols;
   
+  if(p_n_rows == 0)  { return; }
+  
   if(mode == 0) // each column
     {
     for(uword i=0; i < p_n_cols; ++i)
@@ -231,6 +235,8 @@ subview_each1<parent,mode>::operator-= (const Base<eT,T1>& in)
   const uword p_n_rows = p.n_rows;
   const uword p_n_cols = p.n_cols;
   
+  if(p_n_rows == 0)  { return; }
+  
   if(mode == 0) // each column
     {
     for(uword i=0; i < p_n_cols; ++i)
@@ -268,6 +274,8 @@ subview_each1<parent,mode>::operator%= (const Base<eT,T1>& in)
   const uword p_n_rows = p.n_rows;
   const uword p_n_cols = p.n_cols;
   
+  if(p_n_rows == 0)  { return; }
+  
   if(mode == 0) // each column
     {
     for(uword i=0; i < p_n_cols; ++i)
@@ -305,6 +313,8 @@ subview_each1<parent,mode>::operator/= (const Base<eT,T1>& in)
   const uword p_n_rows = p.n_rows;
   const uword p_n_cols = p.n_cols;
   
+  if(p_n_rows == 0)  { return; }
+  
   if(mode == 0) // each column
     {
     for(uword i=0; i < p_n_cols; ++i)
@@ -400,6 +410,8 @@ subview_each2<parent,mode,TB>::operator= (const Base<eT,T1>& in)
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       arrayops::copy( p.colptr(col), A_mem, p_n_rows );
       }
     }
@@ -456,6 +468,8 @@ subview_each2<parent,mode,TB>::operator+= (const Base<eT,T1>& in)
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       arrayops::inplace_plus( p.colptr(col), A_mem, p_n_rows );
       }
     }
@@ -509,6 +523,8 @@ subview_each2<parent,mode,TB>::operator-= (const Base<eT,T1>& in)
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       arrayops::inplace_minus( p.colptr(col), A_mem, p_n_rows );
       }
     }
@@ -562,6 +578,8 @@ subview_each2<parent,mode,TB>::operator%= (const Base<eT,T1>& in)
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       arrayops::inplace_mul( p.colptr(col), A_mem, p_n_rows );
       }
     }
@@ -615,6 +633,8 @@ subview_each2<parent,mode,TB>::operator/= (const Base<eT,T1>& in)
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       arrayops::inplace_div( p.colptr(col), A_mem, p_n_rows );
       }
     }
@@ -666,32 +686,35 @@ subview_each1_aux::operator_plus
   
   const eT* A_mem = A.memptr();
   
-  if(mode == 0) // each column
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-    for(uword i=0; i < p_n_cols; ++i)
+    if(mode == 0) // each column
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = p_mem[row] + A_mem[row];
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = p_mem[row] + A_mem[row];
+          }
         }
       }
-    }
-  
-  if(mode == 1) // each row
-    {
-    for(uword i=0; i < p_n_cols; ++i)
+    
+    if(mode == 1) // each row
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      const eT A_val = A_mem[i];
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = p_mem[row] + A_val;
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        const eT A_val = A_mem[i];
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = p_mem[row] + A_val;
+          }
         }
       }
     }
@@ -728,32 +751,35 @@ subview_each1_aux::operator_minus
   
   const eT* A_mem = A.memptr();
   
-  if(mode == 0) // each column
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-    for(uword i=0; i < p_n_cols; ++i)
+    if(mode == 0) // each column
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = p_mem[row] - A_mem[row];
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = p_mem[row] - A_mem[row];
+          }
         }
       }
-    }
-  
-  if(mode == 1) // each row
-    {
-    for(uword i=0; i < p_n_cols; ++i)
+    
+    if(mode == 1) // each row
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      const eT A_val = A_mem[i];
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = p_mem[row] - A_val;
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        const eT A_val = A_mem[i];
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = p_mem[row] - A_val;
+          }
         }
       }
     }
@@ -790,32 +816,35 @@ subview_each1_aux::operator_minus
   
   const eT* A_mem = A.memptr();
   
-  if(mode == 0) // each column
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-    for(uword i=0; i < p_n_cols; ++i)
+    if(mode == 0) // each column
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = A_mem[row] - p_mem[row];
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = A_mem[row] - p_mem[row];
+          }
         }
       }
-    }
-  
-  if(mode == 1) // each row
-    {
-    for(uword i=0; i < p_n_cols; ++i)
+    
+    if(mode == 1) // each row
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      const eT A_val = A_mem[i];
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = A_val - p_mem[row];
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        const eT A_val = A_mem[i];
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = A_val - p_mem[row];
+          }
         }
       }
     }
@@ -852,32 +881,35 @@ subview_each1_aux::operator_schur
   
   const eT* A_mem = A.memptr();
   
-  if(mode == 0) // each column
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-    for(uword i=0; i < p_n_cols; ++i)
+    if(mode == 0) // each column
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = p_mem[row] * A_mem[row];
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = p_mem[row] * A_mem[row];
+          }
         }
       }
-    }
-  
-  if(mode == 1) // each row
-    {
-    for(uword i=0; i < p_n_cols; ++i)
+    
+    if(mode == 1) // each row
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      const eT A_val = A_mem[i];
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = p_mem[row] * A_val;
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        const eT A_val = A_mem[i];
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = p_mem[row] * A_val;
+          }
         }
       }
     }
@@ -914,32 +946,35 @@ subview_each1_aux::operator_div
   
   const eT* A_mem = A.memptr();
   
-  if(mode == 0) // each column
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-    for(uword i=0; i < p_n_cols; ++i)
+    if(mode == 0) // each column
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = p_mem[row] / A_mem[row];
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = p_mem[row] / A_mem[row];
+          }
         }
       }
-    }
-  
-  if(mode == 1) // each row
-    {
-    for(uword i=0; i < p_n_cols; ++i)
+    
+    if(mode == 1) // each row
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      const eT A_val = A_mem[i];
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = p_mem[row] / A_val;
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        const eT A_val = A_mem[i];
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = p_mem[row] / A_val;
+          }
         }
       }
     }
@@ -976,32 +1011,35 @@ subview_each1_aux::operator_div
   
   const eT* A_mem = A.memptr();
   
-  if(mode == 0) // each column
+  if( (p_n_rows != 0) && (p_n_cols != 0) )
     {
-    for(uword i=0; i < p_n_cols; ++i)
+    if(mode == 0) // each column
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = A_mem[row] / p_mem[row];
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = A_mem[row] / p_mem[row];
+          }
         }
       }
-    }
-  
-  if(mode == 1) // each row
-    {
-    for(uword i=0; i < p_n_cols; ++i)
+    
+    if(mode == 1) // each row
       {
-      const eT*   p_mem =   p.colptr(i);
-            eT* out_mem = out.colptr(i);
-      
-      const eT A_val = A_mem[i];
-      
-      for(uword row=0; row < p_n_rows; ++row)
+      for(uword i=0; i < p_n_cols; ++i)
         {
-        out_mem[row] = A_val / p_mem[row];
+        const eT*   p_mem =   p.colptr(i);
+              eT* out_mem = out.colptr(i);
+        
+        const eT A_val = A_mem[i];
+        
+        for(uword row=0; row < p_n_rows; ++row)
+          {
+          out_mem[row] = A_val / p_mem[row];
+          }
         }
       }
     }
@@ -1058,6 +1096,8 @@ subview_each2_aux::operator_plus
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       arrayops::inplace_plus( out.colptr(col), A_mem, p_n_rows );
       }
     }
@@ -1120,6 +1160,8 @@ subview_each2_aux::operator_minus
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       arrayops::inplace_minus( out.colptr(col), A_mem, p_n_rows );
       }
     }
@@ -1182,6 +1224,8 @@ subview_each2_aux::operator_minus
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       const eT*   p_mem =   p.colptr(col);
             eT* out_mem = out.colptr(col);
       
@@ -1250,6 +1294,8 @@ subview_each2_aux::operator_schur
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       arrayops::inplace_mul( out.colptr(col), A_mem, p_n_rows );
       }
     }
@@ -1312,6 +1358,8 @@ subview_each2_aux::operator_div
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       arrayops::inplace_div( out.colptr(col), A_mem, p_n_rows );
       }
     }
@@ -1374,6 +1422,8 @@ subview_each2_aux::operator_div
       
       arma_conform_check_bounds( (col >= p_n_cols), "each_col(): index out of bounds" );
       
+      if(p_n_rows == 0)  { continue; }
+      
       const eT*   p_mem =   p.colptr(col);
             eT* out_mem = out.colptr(col);
       

include/armadillo_bits/subview_meat.hpp

@@ -95,6 +95,8 @@ subview<eT>::inplace_op(const eT val)
   const uword s_n_rows = s.n_rows;
   const uword s_n_cols = s.n_cols;
   
+  if( (s_n_rows == 0) || (s_n_cols == 0) )  { return; }
+  
   if(s_n_rows == 1)
     {
     Mat<eT>& A = const_cast< Mat<eT>& >(s.m);
@@ -151,6 +153,8 @@ subview<eT>::inplace_op(const Base<eT,T1>& in, const char* identifier)
   
   arma_conform_assert_same_size(s, P, identifier);
   
+  if( (s_n_rows == 0) || (s_n_cols == 0) )  { return; }
+  
   const bool use_mp      = arma_config::openmp && Proxy<T1>::use_mp && mp_gate<eT>::eval(s.n_elem);
   const bool has_overlap = P.has_overlap(s);
   
@@ -348,8 +352,10 @@ subview<eT>::inplace_op(const subview<eT>& x, const char* identifier)
   
   arma_conform_assert_same_size(s, x, identifier);
   
-  const uword s_n_cols = s.n_cols;
   const uword s_n_rows = s.n_rows;
+  const uword s_n_cols = s.n_cols;
+  
+  if( (s_n_rows == 0) || (s_n_cols == 0) )  { return; }
   
   if(s_n_rows == 1)
     {
@@ -606,7 +612,8 @@ subview<eT>::operator=(const SpBase<eT, T1>& x)
   // Clear the subview.
   zeros();
   
-  // Iterate through the sparse subview and set the nonzero values appropriately.
+  if(p.get_n_nonzero() == 0)  { return; }
+  
   typename SpProxy<T1>::const_iterator_type cit     = p.begin();
   typename SpProxy<T1>::const_iterator_type cit_end = p.end();
   
@@ -631,7 +638,8 @@ subview<eT>::operator+=(const SpBase<eT, T1>& x)
   
   arma_conform_assert_same_size(n_rows, n_cols, p.get_n_rows(), p.get_n_cols(), "addition");
   
-  // Iterate through the sparse subview and add its values.
+  if(p.get_n_nonzero() == 0)  { return; }
+  
   typename SpProxy<T1>::const_iterator_type cit     = p.begin();
   typename SpProxy<T1>::const_iterator_type cit_end = p.end();
   
@@ -656,7 +664,8 @@ subview<eT>::operator-=(const SpBase<eT, T1>& x)
   
   arma_conform_assert_same_size(n_rows, n_cols, p.get_n_rows(), p.get_n_cols(), "subtraction");
   
-  // Iterate through the sparse subview and subtract its values.
+  if(p.get_n_nonzero() == 0)  { return; }
+  
   typename SpProxy<T1>::const_iterator_type cit     = p.begin();
   typename SpProxy<T1>::const_iterator_type cit_end = p.end();
   
@@ -725,13 +734,12 @@ subview<eT>::operator/=(const SpBase<eT, T1>& x)
   {
   arma_debug_sigprint();
   
+  // NOTE: use of this function is not advised; it is implemented only for completeness
+  
   const SpProxy<T1> p(x.get_ref());
   
   arma_conform_assert_same_size(n_rows, n_cols, p.get_n_rows(), p.get_n_cols(), "element-wise division");
   
-  // This is probably going to fill your subview with a bunch of NaNs,
-  // so I'm not going to bother to implement it fast.
-  // You can have slow NaNs.  They're fine too.
   for(uword c = 0; c < n_cols; ++c)
   for(uword r = 0; r < n_rows; ++r)
     {
@@ -968,8 +976,10 @@ subview<eT>::replace(const eT old_val, const eT new_val)
   
   subview<eT>& s = *this;
   
-  const uword s_n_cols = s.n_cols;
   const uword s_n_rows = s.n_rows;
+  const uword s_n_cols = s.n_cols;
+  
+  if( (s_n_rows == 0) || (s_n_cols == 0) )  { return; }
   
   if(s_n_rows == 1)
     {
@@ -1018,8 +1028,10 @@ subview<eT>::clean(const typename get_pod_type<eT>::result threshold)
   
   subview<eT>& s = *this;
   
-  const uword s_n_cols = s.n_cols;
   const uword s_n_rows = s.n_rows;
+  const uword s_n_cols = s.n_cols;
+  
+  if(s_n_rows == 0)  { return; }
   
   for(uword ucol=0; ucol < s_n_cols; ++ucol)
     {
@@ -1048,8 +1060,10 @@ subview<eT>::clamp(const eT min_val, const eT max_val)
   
   subview<eT>& s = *this;
   
-  const uword s_n_cols = s.n_cols;
   const uword s_n_rows = s.n_rows;
+  const uword s_n_cols = s.n_cols;
+  
+  if(s_n_rows == 0)  { return; }
   
   for(uword ucol=0; ucol < s_n_cols; ++ucol)
     {
@@ -1068,8 +1082,10 @@ subview<eT>::fill(const eT val)
   
   subview<eT>& s = *this;
   
-  const uword s_n_cols = s.n_cols;
   const uword s_n_rows = s.n_rows;
+  const uword s_n_cols = s.n_cols;
+  
+  if( (s_n_rows == 0) || (s_n_cols == 0) )  { return; }
   
   if(s_n_rows == 1)
     {
@@ -1109,7 +1125,42 @@ subview<eT>::zeros()
   {
   arma_debug_sigprint();
   
-  (*this).fill(eT(0));
+  subview<eT>& s = *this;
+  
+  const uword s_n_rows = s.n_rows;
+  const uword s_n_cols = s.n_cols;
+  
+  if( (s_n_rows == 0) || (s_n_cols == 0) )  { return; }
+  
+  if(s_n_rows == 1)
+    {
+    Mat<eT>& A = const_cast< Mat<eT>& >(s.m);
+    
+    const uword A_n_rows = A.n_rows;
+    
+    eT* Aptr = &(A.at(s.aux_row1,s.aux_col1));
+    
+    constexpr eT eT_zero = eT(0);
+    
+    for(uword ii=0; ii < s_n_cols; ++ii)
+      {
+      (*Aptr) = eT_zero;  Aptr += A_n_rows;
+      }
+    }
+  else
+    {
+    if( (s.aux_row1 == 0) && (s_n_rows == s.m.n_rows) )
+      {
+      arrayops::fill_zeros( s.colptr(0), s.n_elem );
+      }
+    else
+      {
+      for(uword ucol=0; ucol < s_n_cols; ++ucol)
+        {
+        arrayops::fill_zeros( s.colptr(ucol), s_n_rows );
+        }
+      }
+    }
   }
 
 
@@ -1157,6 +1208,8 @@ subview<eT>::randu()
   const uword s_n_rows = s.n_rows;
   const uword s_n_cols = s.n_cols;
   
+  if( (s_n_rows == 0) || (s_n_cols == 0) )  { return; }
+  
   if(s_n_rows == 1)
     {
     podarray<eT> tmp(s_n_cols);
@@ -1197,6 +1250,8 @@ subview<eT>::randn()
   const uword s_n_rows = s.n_rows;
   const uword s_n_cols = s.n_cols;
   
+  if( (s_n_rows == 0) || (s_n_cols == 0) )  { return; }
+  
   if(s_n_rows == 1)
     {
     podarray<eT> tmp(s_n_cols);
@@ -1410,7 +1465,7 @@ arma_inline
 eT*
 subview<eT>::colptr(const uword in_col)
   {
-  return & access::rw((const_cast< Mat<eT>& >(m)).mem[ (in_col + aux_col1)*m.n_rows + aux_row1 ]);
+  return access::rwp( m.mem + ((in_col + aux_col1)*m.n_rows + aux_row1) );
   }
 
 
@@ -1420,7 +1475,27 @@ arma_inline
 const eT*
 subview<eT>::colptr(const uword in_col) const
   {
-  return & m.mem[ (in_col + aux_col1)*m.n_rows + aux_row1 ];
+  return m.mem + ((in_col + aux_col1)*m.n_rows + aux_row1);
+  }
+
+
+
+template<typename eT>
+arma_inline
+eT*
+subview<eT>::startptr()
+  {
+  return access::rwp( m.mem + (aux_col1*m.n_rows + aux_row1) );
+  }
+
+
+
+template<typename eT>
+arma_inline
+const eT*
+subview<eT>::startptr() const
+  {
+  return m.mem + (aux_col1*m.n_rows + aux_row1);
   }
 
 
@@ -1483,9 +1558,12 @@ subview<eT>::is_finite() const
   const uword local_n_rows = n_rows;
   const uword local_n_cols = n_cols;
   
-  for(uword ii=0; ii<local_n_cols; ++ii)
+  if(local_n_rows != 0)
     {
-    if(arrayops::is_finite(colptr(ii), local_n_rows) == false)  { return false; }
+    for(uword ii=0; ii<local_n_cols; ++ii)
+      {
+      if(arrayops::is_finite(colptr(ii), local_n_rows) == false)  { return false; }
+      }
     }
   
   return true;
@@ -1503,9 +1581,12 @@ subview<eT>::is_zero(const typename get_pod_type<eT>::result tol) const
   const uword local_n_rows = n_rows;
   const uword local_n_cols = n_cols;
   
-  for(uword ii=0; ii<local_n_cols; ++ii)
+  if(local_n_rows != 0)
     {
-    if(arrayops::is_zero(colptr(ii), local_n_rows, tol) == false)  { return false; }
+    for(uword ii=0; ii<local_n_cols; ++ii)
+      {
+      if(arrayops::is_zero(colptr(ii), local_n_rows, tol) == false)  { return false; }
+      }
     }
   
   return true;
@@ -1525,9 +1606,12 @@ subview<eT>::has_inf() const
   const uword local_n_rows = n_rows;
   const uword local_n_cols = n_cols;
   
-  for(uword ii=0; ii<local_n_cols; ++ii)
+  if(local_n_rows != 0)
     {
-    if(arrayops::has_inf(colptr(ii), local_n_rows))  { return true; }
+    for(uword ii=0; ii<local_n_cols; ++ii)
+      {
+      if(arrayops::has_inf(colptr(ii), local_n_rows))  { return true; }
+      }
     }
   
   return false;
@@ -1547,9 +1631,12 @@ subview<eT>::has_nan() const
   const uword local_n_rows = n_rows;
   const uword local_n_cols = n_cols;
   
-  for(uword ii=0; ii<local_n_cols; ++ii)
+  if(local_n_rows != 0)
     {
-    if(arrayops::has_nan(colptr(ii), local_n_rows))  { return true; }
+    for(uword ii=0; ii<local_n_cols; ++ii)
+      {
+      if(arrayops::has_nan(colptr(ii), local_n_rows))  { return true; }
+      }
     }
   
   return false;
@@ -1569,9 +1656,12 @@ subview<eT>::has_nonfinite() const
   const uword local_n_rows = n_rows;
   const uword local_n_cols = n_cols;
   
-  for(uword ii=0; ii<local_n_cols; ++ii)
+  if(local_n_rows != 0)
     {
-    if(arrayops::is_finite(colptr(ii), local_n_rows) == false)  { return true; }
+    for(uword ii=0; ii<local_n_cols; ++ii)
+      {
+      if(arrayops::is_finite(colptr(ii), local_n_rows) == false)  { return true; }
+      }
     }
   
   return false;
@@ -1590,64 +1680,66 @@ subview<eT>::extract(Mat<eT>& out, const subview<eT>& in)
   // NOTE: we're assuming that the matrix has already been set to the correct size and there is no aliasing;
   // size setting and alias checking is done by either the Mat constructor or operator=()
   
-  const uword n_rows = in.n_rows;  // number of rows in the subview
-  const uword n_cols = in.n_cols;  // number of columns in the subview
-  
   arma_debug_print(arma_str::format("out.n_rows: %u; out.n_cols: %u; in.m.n_rows: %u; in.m.n_cols: %u") % out.n_rows % out.n_cols % in.m.n_rows % in.m.n_cols );
   
+  const uword n_rows = in.n_rows;
+  const uword n_cols = in.n_cols;
   
-  if(in.is_vec())
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
+  if(n_cols == 1)
     {
-    if(n_cols == 1)   // a column vector
-      {
-      arma_debug_print("subview::extract(): copying col");
-      
-      // in.colptr(0) is the first column of the subview, taking into account any row offset
-      arrayops::copy( out.memptr(), in.colptr(0), n_rows );
-      }
-    else
-    if(n_rows == 1)   // a row vector
-      {
-      arma_debug_print("subview::extract(): copying row)");
-      
-      eT* out_mem = out.memptr();
-      
-      const uword X_n_rows = in.m.n_rows;
-      
-      const eT* Xptr = &(in.m.at(in.aux_row1,in.aux_col1));
-      
-      uword j;
-      
-      for(j=1; j < n_cols; j+=2)
-        {
-        const eT tmp1 = (*Xptr);  Xptr += X_n_rows;
-        const eT tmp2 = (*Xptr);  Xptr += X_n_rows;
-        
-        (*out_mem) = tmp1;  out_mem++;
-        (*out_mem) = tmp2;  out_mem++;
-        }
-      
-      if((j-1) < n_cols)
-        {
-        (*out_mem) = (*Xptr);
-        }
-      }
-    }
-  else   // general submatrix
-    {
-    arma_debug_print("subview::extract(): general submatrix");
+    arma_debug_print("subview::extract(): copying col");
     
-    if( (in.aux_row1 == 0) && (n_rows == in.m.n_rows) )
+    // in.colptr(0) is the first column of the subview, taking into account any row offset
+    arrayops::copy( out.memptr(), in.colptr(0), n_rows );
+    
+    return;
+    }
+  
+  if(n_rows == 1)
+    {
+    arma_debug_print("subview::extract(): copying row");
+    
+    eT* out_mem = out.memptr();
+    
+    const uword X_n_rows = in.m.n_rows;
+    
+    const eT* Xptr = &(in.m.at(in.aux_row1,in.aux_col1));
+    
+    uword j;
+    
+    for(j=1; j < n_cols; j+=2)
       {
-      arrayops::copy( out.memptr(), in.colptr(0), in.n_elem );
+      const eT tmp1 = (*Xptr);  Xptr += X_n_rows;
+      const eT tmp2 = (*Xptr);  Xptr += X_n_rows;
+      
+      (*out_mem) = tmp1;  out_mem++;
+      (*out_mem) = tmp2;  out_mem++;
       }
-    else
+    
+    if((j-1) < n_cols)
       {
-      for(uword col=0; col < n_cols; ++col)
-        {
-        arrayops::copy( out.colptr(col), in.colptr(col), n_rows );
-        }
+      (*out_mem) = (*Xptr);
       }
+    
+    return;
+    }
+  
+  if( (in.aux_row1 == 0) && (n_rows == in.m.n_rows) )
+    {
+    arma_debug_print("subview::extract(): contiguous submatrix");
+    
+    arrayops::copy( out.memptr(), in.colptr(0), in.n_elem );
+    
+    return;
+    }
+    
+  arma_debug_print("subview::extract(): general submatrix");
+  
+  for(uword col=0; col < n_cols; ++col)
+    {
+    arrayops::copy( out.colptr(col), in.colptr(col), n_rows );
     }
   }
 
@@ -1666,6 +1758,8 @@ subview<eT>::plus_inplace(Mat<eT>& out, const subview<eT>& in)
   const uword n_rows = in.n_rows;
   const uword n_cols = in.n_cols;
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
   if(n_rows == 1)
     {
     eT* out_mem = out.memptr();
@@ -1714,6 +1808,8 @@ subview<eT>::minus_inplace(Mat<eT>& out, const subview<eT>& in)
   const uword n_rows = in.n_rows;
   const uword n_cols = in.n_cols;
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
   if(n_rows == 1)
     {
     eT* out_mem = out.memptr();
@@ -1762,6 +1858,8 @@ subview<eT>::schur_inplace(Mat<eT>& out, const subview<eT>& in)
   const uword n_rows = in.n_rows;
   const uword n_cols = in.n_cols;
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
   if(n_rows == 1)
     {
     eT* out_mem = out.memptr();
@@ -1810,6 +1908,8 @@ subview<eT>::div_inplace(Mat<eT>& out, const subview<eT>& in)
   const uword n_rows = in.n_rows;
   const uword n_cols = in.n_cols;
   
+  if( (n_rows == 0) || (n_cols == 0) )  { return; }
+  
   if(n_rows == 1)
     {
     eT* out_mem = out.memptr();
@@ -2377,9 +2477,12 @@ subview<eT>::each_col(const std::function< void(Col<eT>&) >& F)
   {
   arma_debug_sigprint();
   
-  for(uword ii=0; ii < n_cols; ++ii)
+  const uword local_n_rows = n_rows;
+  const uword local_n_cols = n_cols;
+  
+  for(uword ii=0; ii < local_n_cols; ++ii)
     {
-    Col<eT> tmp(colptr(ii), n_rows, false, true);
+    Col<eT> tmp(colptr(ii), local_n_rows, false, true);
     F(tmp);
     }
   }
@@ -2393,9 +2496,12 @@ subview<eT>::each_col(const std::function< void(const Col<eT>&) >& F) const
   {
   arma_debug_sigprint();
   
-  for(uword ii=0; ii < n_cols; ++ii)
+  const uword local_n_rows = n_rows;
+  const uword local_n_cols = n_cols;
+  
+  for(uword ii=0; ii < local_n_cols; ++ii)
     {
-    const Col<eT> tmp(colptr(ii), n_rows, false, true);
+    const Col<eT> tmp(colptr(ii), local_n_rows, false, true);
     F(tmp);
     }
   }
@@ -2410,20 +2516,23 @@ subview<eT>::each_row(const std::function< void(Row<eT>&) >& F)
   {
   arma_debug_sigprint();
   
-  podarray<eT> array1(n_cols);
-  podarray<eT> array2(n_cols);
+  const uword local_n_rows = n_rows;
+  const uword local_n_cols = n_cols;
   
-  Row<eT> tmp1( array1.memptr(), n_cols, false, true );
-  Row<eT> tmp2( array2.memptr(), n_cols, false, true );
+  podarray<eT> array1(local_n_cols);
+  podarray<eT> array2(local_n_cols);
+  
+  Row<eT> tmp1( array1.memptr(), local_n_cols, false, true );
+  Row<eT> tmp2( array2.memptr(), local_n_cols, false, true );
   
   eT* tmp1_mem = tmp1.memptr();
   eT* tmp2_mem = tmp2.memptr();
   
   uword ii, jj;
   
-  for(ii=0, jj=1; jj < n_rows; ii+=2, jj+=2)
+  for(ii=0, jj=1; jj < local_n_rows; ii+=2, jj+=2)
     {
-    for(uword col_id = 0; col_id < n_cols; ++col_id)
+    for(uword col_id = 0; col_id < local_n_cols; ++col_id)
       {
       const eT* col_mem = colptr(col_id);
       
@@ -2434,7 +2543,7 @@ subview<eT>::each_row(const std::function< void(Row<eT>&) >& F)
     F(tmp1);
     F(tmp2);
     
-    for(uword col_id = 0; col_id < n_cols; ++col_id)
+    for(uword col_id = 0; col_id < local_n_cols; ++col_id)
       {
       eT* col_mem = colptr(col_id);
       
@@ -2443,7 +2552,7 @@ subview<eT>::each_row(const std::function< void(Row<eT>&) >& F)
       }
     }
   
-  if(ii < n_rows)
+  if(ii < local_n_rows)
     {
     tmp1 = (*this).row(ii);
     
@@ -2462,20 +2571,23 @@ subview<eT>::each_row(const std::function< void(const Row<eT>&) >& F) const
   {
   arma_debug_sigprint();
   
-  podarray<eT> array1(n_cols);
-  podarray<eT> array2(n_cols);
+  const uword local_n_rows = n_rows;
+  const uword local_n_cols = n_cols;
   
-  Row<eT> tmp1( array1.memptr(), n_cols, false, true );
-  Row<eT> tmp2( array2.memptr(), n_cols, false, true );
+  podarray<eT> array1(local_n_cols);
+  podarray<eT> array2(local_n_cols);
+  
+  Row<eT> tmp1( array1.memptr(), local_n_cols, false, true );
+  Row<eT> tmp2( array2.memptr(), local_n_cols, false, true );
   
   eT* tmp1_mem = tmp1.memptr();
   eT* tmp2_mem = tmp2.memptr();
   
   uword ii, jj;
   
-  for(ii=0, jj=1; jj < n_rows; ii+=2, jj+=2)
+  for(ii=0, jj=1; jj < local_n_rows; ii+=2, jj+=2)
     {
-    for(uword col_id = 0; col_id < n_cols; ++col_id)
+    for(uword col_id = 0; col_id < local_n_cols; ++col_id)
       {
       const eT* col_mem = colptr(col_id);
       
@@ -2487,7 +2599,7 @@ subview<eT>::each_row(const std::function< void(const Row<eT>&) >& F) const
     F(tmp2);
     }
   
-  if(ii < n_rows)
+  if(ii < local_n_rows)
     {
     tmp1 = (*this).row(ii);
     
@@ -3264,7 +3376,7 @@ template<typename eT>
 inline
 subview_col<eT>::subview_col(const Mat<eT>& in_m, const uword in_col)
   : subview<eT>(in_m, 0, in_col, in_m.n_rows, 1)
-  , colmem(subview<eT>::colptr(0)) 
+  , colmem(subview<eT>::startptr()) 
   {
   arma_debug_sigprint();
   }
@@ -3275,7 +3387,7 @@ template<typename eT>
 inline
 subview_col<eT>::subview_col(const Mat<eT>& in_m, const uword in_col, const uword in_row1, const uword in_n_rows)
   : subview<eT>(in_m, in_row1, in_col, in_n_rows, 1)
-  , colmem(subview<eT>::colptr(0)) 
+  , colmem(subview<eT>::startptr()) 
   {
   arma_debug_sigprint();
   }
@@ -4268,7 +4380,7 @@ template<typename eT>
 inline
 subview_row<eT>::subview_row(const Mat<eT>& in_m, const uword in_row)
   : subview<eT>(in_m, in_row, 0, 1, in_m.n_cols)
-  , rowmem(subview<eT>::colptr(0))
+  , rowmem(subview<eT>::startptr())
   {
   arma_debug_sigprint();
   }
@@ -4279,7 +4391,7 @@ template<typename eT>
 inline
 subview_row<eT>::subview_row(const Mat<eT>& in_m, const uword in_row, const uword in_col1, const uword in_n_cols)
   : subview<eT>(in_m, in_row, in_col1, 1, in_n_cols)
-  , rowmem(subview<eT>::colptr(0))
+  , rowmem(subview<eT>::startptr())
   {
   arma_debug_sigprint();
   }