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// 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 fn_log_det
//! @{
//! log determinant of mat
template<typename T1>
inline
void
log_det
(
typename T1::elem_type& out_val,
typename T1::pod_type& out_sign,
const Base<typename T1::elem_type,T1>& X,
const typename arma_blas_type_only<typename T1::elem_type>::result* junk = 0
)
{
arma_extra_debug_sigprint();
arma_ignore(junk);
typedef typename T1::elem_type eT;
typedef typename T1::pod_type T;
const bool status = auxlib::log_det(out_val, out_sign, X);
if(status == false)
{
out_val = eT(Datum<T>::nan);
out_sign = T(0);
arma_warn("log_det(): failed to find determinant");
}
}
template<typename T1>
inline
void
log_det
(
typename T1::elem_type& out_val,
typename T1::pod_type& out_sign,
const Op<T1,op_diagmat>& X,
const typename arma_blas_type_only<typename T1::elem_type>::result* junk = 0
)
{
arma_extra_debug_sigprint();
arma_ignore(junk);
typedef typename T1::elem_type eT;
typedef typename T1::pod_type T;
const diagmat_proxy<T1> A(X.m);
arma_debug_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;
}
eT x = A[0];
T sign = (is_cx<eT>::no) ? ( (access::tmp_real(x) < T(0)) ? -1 : +1 ) : +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)) ? -1 : +1 ) : +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;
}
template<typename T1>
inline
arma_warn_unused
std::complex<typename T1::pod_type>
log_det
(
const Base<typename T1::elem_type,T1>& X,
const typename arma_blas_type_only<typename T1::elem_type>::result* junk = 0
)
{
arma_extra_debug_sigprint();
arma_ignore(junk);
typedef typename T1::elem_type eT;
typedef typename T1::pod_type T;
eT out_val = eT(0);
T out_sign = T(0);
log_det(out_val, out_sign, X.get_ref());
return (out_sign >= T(1)) ? std::complex<T>(out_val) : (out_val + std::complex<T>(T(0),Datum<T>::pi));
}
//! @}
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