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armadillo-code/include/armadillo_bits/op_inv_spd_meat.hpp
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// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------
//! \addtogroup op_inv_spd
//! @{
template<typename T1>
inline
void
op_inv_spd_default::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv_spd_default>& X)
{
arma_debug_sigprint();
const bool status = op_inv_spd_default::apply_direct(out, X.m);
if(status == false)
{
out.soft_reset();
arma_stop_runtime_error("inv_sympd(): matrix is singular or not positive definite");
}
}
template<typename T1>
inline
bool
op_inv_spd_default::apply_direct(Mat<typename T1::elem_type>& out, const Base<typename T1::elem_type,T1>& expr)
{
arma_debug_sigprint();
return op_inv_spd_full::apply_direct<T1,false>(out, expr, uword(0));
}
//
template<typename T1>
inline
void
op_inv_spd_full::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv_spd_full>& X)
{
arma_debug_sigprint();
const uword flags = X.aux_uword_a;
const bool status = op_inv_spd_full::apply_direct(out, X.m, flags);
if(status == false)
{
out.soft_reset();
arma_stop_runtime_error("inv_sympd(): matrix is singular or not positive definite");
}
}
template<typename T1, const bool has_user_flags>
inline
bool
op_inv_spd_full::apply_direct(Mat<typename T1::elem_type>& out, const Base<typename T1::elem_type,T1>& expr, const uword flags)
{
arma_debug_sigprint();
typedef typename T1::elem_type eT;
typedef typename T1::pod_type T;
if(has_user_flags == true ) { arma_debug_print("op_inv_spd_full: has_user_flags = true"); }
if(has_user_flags == false) { arma_debug_print("op_inv_spd_full: has_user_flags = false"); }
const bool fast = has_user_flags && bool(flags & inv_opts::flag_fast );
const bool allow_approx = has_user_flags && bool(flags & inv_opts::flag_allow_approx);
const bool no_ugly = has_user_flags && bool(flags & inv_opts::flag_no_ugly );
if(has_user_flags)
{
arma_debug_print("op_inv_spd_full: enabled flags:");
if(fast ) { arma_debug_print("fast"); }
if(allow_approx) { arma_debug_print("allow_approx"); }
if(no_ugly ) { arma_debug_print("no_ugly"); }
arma_conform_check( (fast && allow_approx), "inv_sympd(): options 'fast' and 'allow_approx' are mutually exclusive" );
arma_conform_check( (fast && no_ugly ), "inv_sympd(): options 'fast' and 'no_ugly' are mutually exclusive" );
arma_conform_check( (no_ugly && allow_approx), "inv_sympd(): options 'no_ugly' and 'allow_approx' are mutually exclusive" );
}
if(no_ugly)
{
op_inv_spd_state<T> inv_state;
const bool status = op_inv_spd_rcond::apply_direct(out, inv_state, expr);
// workaround for bug in gcc 4.8
const uword local_size = inv_state.size;
const T local_rcond = inv_state.rcond;
if((status == false) || (local_rcond < ((std::max)(local_size, uword(1)) * std::numeric_limits<T>::epsilon())) || arma_isnan(local_rcond)) { return false; }
return true;
}
if(allow_approx)
{
op_inv_spd_state<T> inv_state;
Mat<eT> tmp;
const bool status = op_inv_spd_rcond::apply_direct(tmp, inv_state, expr);
// workaround for bug in gcc 4.8
const uword local_size = inv_state.size;
const T local_rcond = inv_state.rcond;
if((status == false) || (local_rcond < ((std::max)(local_size, uword(1)) * std::numeric_limits<T>::epsilon())) || arma_isnan(local_rcond))
{
const Mat<eT> A = expr.get_ref();
if(inv_state.is_diag) { return op_pinv::apply_diag(out, A, T(0)); }
return op_pinv::apply_sym(out, A, T(0), uword(0));
}
out.steal_mem(tmp);
return true;
}
out = expr.get_ref();
arma_conform_check( (out.is_square() == false), "inv_sympd(): given matrix must be square sized", [&](){ out.soft_reset(); } );
if((arma_config::check_conform) && (arma_config::warn_level > 0))
{
if(auxlib::rudimentary_sym_check(out) == false)
{
if(is_cx<eT>::no ) { arma_warn(1, "inv_sympd(): given matrix is not symmetric"); }
if(is_cx<eT>::yes) { arma_warn(1, "inv_sympd(): given matrix is not hermitian"); }
}
else
if((is_cx<eT>::yes) && (sym_helper::check_diag_imag(out) == false))
{
arma_warn(1, "inv_sympd(): imaginary components on diagonal are non-zero");
}
}
const uword N = out.n_rows;
if(N == 0) { return true; }
if(is_cx<eT>::no)
{
if(N == 1)
{
const T a = access::tmp_real(out[0]);
out[0] = eT(T(1) / a);
return (a > T(0));
}
else
if(N == 2)
{
const bool status = op_inv_spd_full::apply_tiny_2x2(out);
if(status) { return true; }
}
// fallthrough if optimisation failed
}
if(is_op_diagmat<T1>::value || out.is_diagmat())
{
arma_debug_print("op_inv_spd_full: diag optimisation");
eT* colmem = out.memptr();
for(uword i=0; i<N; ++i)
{
eT& out_ii = colmem[i];
const T out_ii_real = access::tmp_real(out_ii);
if(out_ii_real <= T(0)) { return false; }
out_ii = eT(T(1) / out_ii_real);
colmem += N;
}
return true;
}
bool sympd_state_junk = false;
return auxlib::inv_sympd(out, sympd_state_junk);
}
template<typename eT>
inline
bool
op_inv_spd_full::apply_tiny_2x2(Mat<eT>& X)
{
arma_debug_sigprint();
typedef typename get_pod_type<eT>::result T;
// NOTE: assuming matrix X is square sized
// NOTE: assuming matrix X is symmetric
// NOTE: assuming matrix X is real
constexpr T det_min = std::numeric_limits<T>::epsilon();
constexpr T det_max = T(1) / std::numeric_limits<T>::epsilon();
eT* Xm = X.memptr();
T a = access::tmp_real(Xm[0]);
T c = access::tmp_real(Xm[1]);
T d = access::tmp_real(Xm[3]);
const T det_val = (a*d - c*c);
// positive definite iff all leading principal minors are positive
// a = first leading principal minor (top-left 1x1 submatrix)
// det_val = second leading principal minor (top-left 2x2 submatrix)
if(a <= T(0)) { return false; }
// NOTE: since det_min is positive, this also checks whether det_val is positive
if((det_val < det_min) || (det_val > det_max) || arma_isnan(det_val)) { return false; }
d /= det_val;
c /= det_val;
a /= det_val;
Xm[0] = d;
Xm[1] = -c;
Xm[2] = -c;
Xm[3] = a;
return true;
}
//
template<typename T1>
inline
bool
op_inv_spd_rcond::apply_direct(Mat<typename T1::elem_type>& out, op_inv_spd_state<typename T1::pod_type>& out_state, const Base<typename T1::elem_type,T1>& expr)
{
arma_debug_sigprint();
typedef typename T1::elem_type eT;
typedef typename T1::pod_type T;
out = expr.get_ref();
out_state.size = out.n_rows;
out_state.rcond = T(0);
arma_conform_check( (out.is_square() == false), "inv_sympd(): given matrix must be square sized", [&](){ out.soft_reset(); } );
if((arma_config::check_conform) && (arma_config::warn_level > 0))
{
if(auxlib::rudimentary_sym_check(out) == false)
{
if(is_cx<eT>::no ) { arma_warn(1, "inv_sympd(): given matrix is not symmetric"); }
if(is_cx<eT>::yes) { arma_warn(1, "inv_sympd(): given matrix is not hermitian"); }
}
else
if((is_cx<eT>::yes) && (sym_helper::check_diag_imag(out) == false))
{
arma_warn(1, "inv_sympd(): imaginary components on diagonal are non-zero");
}
}
if(is_op_diagmat<T1>::value || out.is_diagmat())
{
arma_debug_print("op_inv_spd_rcond: diag optimisation");
out_state.is_diag = true;
eT* colmem = out.memptr();
T max_abs_src_val = T(0);
T max_abs_inv_val = T(0);
const uword N = out.n_rows;
for(uword i=0; i<N; ++i)
{
eT& out_ii = colmem[i];
const eT src_val = out_ii;
const eT inv_val = eT(1) / src_val;
if( (src_val == eT(0)) || (access::tmp_real(src_val) <= T(0)) ) { return false; }
out_ii = inv_val;
const T abs_src_val = std::abs(src_val);
const T abs_inv_val = std::abs(inv_val);
max_abs_src_val = (abs_src_val > max_abs_src_val) ? abs_src_val : max_abs_src_val;
max_abs_inv_val = (abs_inv_val > max_abs_inv_val) ? abs_inv_val : max_abs_inv_val;
colmem += N;
}
out_state.rcond = T(1) / (max_abs_src_val * max_abs_inv_val);
return true;
}
if(auxlib::crippled_lapack(out))
{
arma_debug_print("op_inv_spd_rcond: workaround for crippled lapack");
Mat<eT> tmp = out;
bool sympd_state = false;
auxlib::inv_sympd(out, sympd_state);
if(sympd_state == false) { out.soft_reset(); out_state.rcond = T(0); return false; }
out_state.rcond = auxlib::rcond(tmp);
if(out_state.rcond == T(0)) { out.soft_reset(); return false; }
return true;
}
return auxlib::inv_sympd_rcond(out, out_state.rcond);
}
//! @}