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armadillo-code/include/armadillo_bits/op_log_det_meat.hpp
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2024-11-06 12:20:18 +10:00

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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_log_det
//! @{
template<typename T1>
inline
bool
op_log_det::apply_direct(typename T1::elem_type& out_val, typename T1::pod_type& out_sign, const Base<typename T1::elem_type,T1>& expr)
{
arma_debug_sigprint();
typedef typename T1::elem_type eT;
// typedef typename T1::pod_type T;
if(strip_diagmat<T1>::do_diagmat)
{
const strip_diagmat<T1> strip(expr.get_ref());
return op_log_det::apply_diagmat(out_val, out_sign, strip.M);
}
if(strip_trimat<T1>::do_trimat)
{
const strip_trimat<T1> strip(expr.get_ref());
return op_log_det::apply_trimat(out_val, out_sign, strip.M);
}
Mat<eT> A(expr.get_ref());
arma_conform_check( (A.is_square() == false), "log_det(): given matrix must be square sized" );
if(A.is_diagmat()) { return op_log_det::apply_diagmat(out_val, out_sign, A); }
const bool is_triu = trimat_helper::is_triu(A);
const bool is_tril = is_triu ? false : trimat_helper::is_tril(A);
if(is_triu || is_tril) { return op_log_det::apply_trimat(out_val, out_sign, A); }
// const bool try_sympd = arma_config::optimise_sym && sym_helper::guess_sympd(A);
//
// if(try_sympd)
// {
// arma_debug_print("op_log_det: attempting sympd optimisation");
//
// T out_val_real = T(0);
//
// const bool status = auxlib::log_det_sympd(out_val_real, A);
//
// if(status)
// {
// out_val = eT(out_val_real);
// out_sign = T(1);
//
// return true;
// }
//
// arma_debug_print("op_log_det: sympd optimisation failed");
//
// // restore A as it's destroyed by auxlib::log_det_sympd()
// A = expr.get_ref();
//
// // fallthrough to the next return statement
// }
return auxlib::log_det(out_val, out_sign, A);
}
template<typename T1>
inline
bool
op_log_det::apply_diagmat(typename T1::elem_type& out_val, typename T1::pod_type& out_sign, const Base<typename T1::elem_type,T1>& expr)
{
arma_debug_sigprint();
typedef typename T1::elem_type eT;
typedef typename T1::pod_type T;
const diagmat_proxy<T1> A(expr.get_ref());
arma_conform_check( (A.n_rows != A.n_cols), "log_det(): given matrix must be square sized" );
const uword N = (std::min)(A.n_rows, A.n_cols);
if(N == 0)
{
out_val = eT(0);
out_sign = T(1);
return true;
}
eT x = A[0];
T sign = (is_cx<eT>::no) ? ( (access::tmp_real(x) < T(0)) ? T(-1) : T(1) ) : T(1);
eT val = (is_cx<eT>::no) ? std::log( (access::tmp_real(x) < T(0)) ? x*T(-1) : x ) : std::log(x);
for(uword i=1; i<N; ++i)
{
x = A[i];
sign *= (is_cx<eT>::no) ? ( (access::tmp_real(x) < T(0)) ? T(-1) : T(1) ) : T(1);
val += (is_cx<eT>::no) ? std::log( (access::tmp_real(x) < T(0)) ? x*T(-1) : x ) : std::log(x);
}
out_val = val;
out_sign = sign;
return (arma_isnan(out_val) == false);
}
template<typename T1>
inline
bool
op_log_det::apply_trimat(typename T1::elem_type& out_val, typename T1::pod_type& out_sign, const Base<typename T1::elem_type,T1>& expr)
{
arma_debug_sigprint();
typedef typename T1::elem_type eT;
typedef typename T1::pod_type T;
const Proxy<T1> P(expr.get_ref());
const uword N = P.get_n_rows();
arma_conform_check( (N != P.get_n_cols()), "log_det(): given matrix must be square sized" );
if(N == 0)
{
out_val = eT(0);
out_sign = T(1);
return true;
}
eT x = P.at(0,0);
T sign = (is_cx<eT>::no) ? ( (access::tmp_real(x) < T(0)) ? T(-1) : T(1) ) : T(1);
eT val = (is_cx<eT>::no) ? std::log( (access::tmp_real(x) < T(0)) ? x*T(-1) : x ) : std::log(x);
for(uword i=1; i<N; ++i)
{
x = P.at(i,i);
sign *= (is_cx<eT>::no) ? ( (access::tmp_real(x) < T(0)) ? T(-1) : T(1) ) : T(1);
val += (is_cx<eT>::no) ? std::log( (access::tmp_real(x) < T(0)) ? x*T(-1) : x ) : std::log(x);
}
out_val = val;
out_sign = sign;
return (arma_isnan(out_val) == false);
}
//
template<typename T1>
inline
bool
op_log_det_sympd::apply_direct(typename T1::pod_type& out_val, const Base<typename T1::elem_type,T1>& expr)
{
arma_debug_sigprint();
typedef typename T1::elem_type eT;
typedef typename T1::pod_type T;
Mat<eT> A(expr.get_ref());
arma_conform_check( (A.is_square() == false), "log_det_sympd(): given matrix must be square sized" );
if((arma_config::check_conform) && (arma_config::warn_level > 0) && (is_cx<eT>::yes) && (sym_helper::check_diag_imag(A) == false))
{
arma_warn(1, "log_det_sympd(): imaginary components on diagonal are non-zero");
}
if(is_op_diagmat<T1>::value || A.is_diagmat())
{
arma_debug_print("op_log_det_sympd: diag optimisation");
eT* colmem = A.memptr();
out_val = T(0);
const uword N = A.n_rows;
for(uword i=0; i<N; ++i)
{
const eT& A_ii = colmem[i];
const T A_ii_real = access::tmp_real(A_ii);
if(A_ii_real <= T(0)) { return false; }
out_val += std::log(A_ii_real);
colmem += N;
}
return true;
}
if((arma_config::check_conform) && (auxlib::rudimentary_sym_check(A) == false))
{
if(is_cx<eT>::no ) { arma_warn(1, "log_det_sympd(): given matrix is not symmetric"); }
if(is_cx<eT>::yes) { arma_warn(1, "log_det_sympd(): given matrix is not hermitian"); }
}
return auxlib::log_det_sympd(out_val, A);
}
//! @}