From a4bfb4f09689b2a7fb3bd091ea8d13935de08210 Mon Sep 17 00:00:00 2001
From: Shikhar Bhardwaj <shikharbhardwaj68@gmail.com>
Date: Wed, 16 Aug 2017 00:43:32 +0530
Subject: [PATCH] Update documentation with the changes. Unify changes with
 test functions

---
 doc/policies/functiontype.hpp                             | 8 +++++---
 .../core/optimizers/parallel_sgd/sparse_test_function.hpp | 6 +++---
 src/mlpack/core/optimizers/scd/scd_impl.hpp               | 2 +-
 src/mlpack/tests/scd_test.cpp                             | 4 ++--
 4 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/doc/policies/functiontype.hpp b/doc/policies/functiontype.hpp
index a0139f4c1d..81e0545a93 100644
--- a/doc/policies/functiontype.hpp
+++ b/doc/policies/functiontype.hpp
@@ -82,10 +82,12 @@ To evaluate the loss function at the given coordinates, same as the
 \c FunctionType interface.
 
 @code
-void FeatureGradient(const arma::mat& coordinates, const size_t j, double& gradient);
+void FeatureGradient(const arma::mat& coordinates, const size_t j, arma::sp_mat& gradient);
 @endcode
 
 To evaluate the gradient at the given coordinates, where \c gradient is an
-out-param for the required gradient. The out-param is a scalar value, for
-storing the gradient of the jth feature.
+out-param for the required gradient. The out-param is a sparse matrix(with
+dimensions equal to the decision variable), for storing the gradient of the
+jth feature.  The \c gradient matrix is supposed to be non-zero in the jth
+column, which contains the relavant partial gradient.
 */
diff --git a/src/mlpack/core/optimizers/parallel_sgd/sparse_test_function.hpp b/src/mlpack/core/optimizers/parallel_sgd/sparse_test_function.hpp
index e76d55eff5..5f8b7ad04b 100644
--- a/src/mlpack/core/optimizers/parallel_sgd/sparse_test_function.hpp
+++ b/src/mlpack/core/optimizers/parallel_sgd/sparse_test_function.hpp
@@ -67,7 +67,7 @@ class SparseTestFunction
                 const size_t i,
                 arma::sp_mat& gradient) const
   {
-    gradient = arma::sp_mat(1, coordinates.n_cols);
+    gradient.zeros(coordinates.size());
     gradient[i] = 2 * coordinates[i] + bi[i];
   }
 
@@ -76,8 +76,8 @@ class SparseTestFunction
                        const size_t j,
                        arma::sp_mat& gradient) const
   {
-    gradient.set_size(1);
-    gradient[0] = 2 * coordinates[j] + bi[j];
+    gradient.zeros(coordinates.size());
+    gradient[j] = 2 * coordinates[j] + bi[j];
   }
 
  private:
diff --git a/src/mlpack/core/optimizers/scd/scd_impl.hpp b/src/mlpack/core/optimizers/scd/scd_impl.hpp
index e5b046231d..472a99fc74 100644
--- a/src/mlpack/core/optimizers/scd/scd_impl.hpp
+++ b/src/mlpack/core/optimizers/scd/scd_impl.hpp
@@ -53,7 +53,7 @@ double SCD<DescentPolicyType>::Optimize(ResolvableFunctionType& function,
     function.FeatureGradient(iterate, featureIdx, gradient);
 
     // Update the decision variable with the partial gradient.
-    iterate.col(featureIdx) -= stepSize * gradient;
+    iterate -= stepSize * gradient;
 
     // Check for convergence.
     if (i % updateInterval == 0)
diff --git a/src/mlpack/tests/scd_test.cpp b/src/mlpack/tests/scd_test.cpp
index 8af39753ca..f1fbb92757 100644
--- a/src/mlpack/tests/scd_test.cpp
+++ b/src/mlpack/tests/scd_test.cpp
@@ -20,8 +20,8 @@
 #include "test_tools.hpp"
 
 using namespace std;
-using namespace arma;
 using namespace mlpack;
+using namespace mlpack::math;
 using namespace mlpack::optimization;
 using namespace mlpack::optimization::test;
 using namespace mlpack::regression;
@@ -135,7 +135,7 @@ BOOST_AUTO_TEST_CASE(SoftmaxRegressionFeatureGradientTest)
   // Create random class labels.
   arma::Row<size_t> labels(points);
   for (size_t i = 0; i < points; i++)
-    labels(i) = math::RandInt(0, numClasses);
+    labels(i) = RandInt(0, numClasses);
 
   // 2 objects for 2 terms in the cost function. Each term contributes towards
   // the gradient and thus need to be checked independently.