180 lines
3.1 KiB
C++
180 lines
3.1 KiB
C++
// Copyright (C) 2008-2015 National ICT Australia (NICTA)
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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// -------------------------------------------------------------------
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//
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// Written by Conrad Sanderson - http://conradsanderson.id.au
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//! \addtogroup fn_det
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//! @{
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template<typename T1>
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inline
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arma_warn_unused
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typename enable_if2< is_supported_blas_type<typename T1::elem_type>::value, typename T1::elem_type >::result
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det
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(
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const Base<typename T1::elem_type,T1>& X
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)
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{
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arma_extra_debug_sigprint();
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return auxlib::det(X.get_ref());
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}
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template<typename T1>
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inline
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arma_warn_unused
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typename T1::elem_type
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det
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(
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const Op<T1, op_diagmat>& X
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)
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{
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arma_extra_debug_sigprint();
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typedef typename T1::elem_type eT;
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const diagmat_proxy<T1> A(X.m);
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arma_debug_check( (A.n_rows != A.n_cols), "det(): given matrix must be square sized" );
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const uword N = (std::min)(A.n_rows, A.n_cols);
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eT val1 = eT(1);
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eT val2 = eT(1);
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uword i,j;
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for(i=0, j=1; j<N; i+=2, j+=2)
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{
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val1 *= A[i];
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val2 *= A[j];
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}
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if(i < N)
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{
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val1 *= A[i];
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}
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return val1 * val2;
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}
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template<typename T1>
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inline
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arma_warn_unused
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typename T1::elem_type
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det
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(
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const Op<T1, op_trimat>& X
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)
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{
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arma_extra_debug_sigprint();
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typedef typename T1::elem_type eT;
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const Proxy<T1> P(X.m);
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const uword N = P.get_n_rows();
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arma_debug_check( (N != P.get_n_cols()), "det(): given matrix must be square sized" );
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eT val1 = eT(1);
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eT val2 = eT(1);
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uword i,j;
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for(i=0, j=1; j<N; i+=2, j+=2)
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{
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val1 *= P.at(i,i);
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val2 *= P.at(j,j);
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}
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if(i < N)
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{
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val1 *= P.at(i,i);
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}
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return val1 * val2;
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}
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//! determinant of inv(A), without doing the inverse operation
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template<typename T1>
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inline
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arma_warn_unused
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typename enable_if2< is_supported_blas_type<typename T1::elem_type>::value, typename T1::elem_type >::result
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det
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(
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const Op<T1,op_inv>& X
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)
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{
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arma_extra_debug_sigprint();
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typedef typename T1::elem_type eT;
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const eT tmp = det(X.m);
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if(tmp == eT(0)) { arma_debug_warn("det(): denominator is zero" ); }
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return eT(1) / tmp;
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}
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template<typename T1>
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inline
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arma_warn_unused
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typename enable_if2< is_supported_blas_type<typename T1::elem_type>::value, typename T1::elem_type >::result
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det
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(
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const Base<typename T1::elem_type,T1>& X,
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const bool // argument kept only for compatibility with old user code
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)
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{
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arma_extra_debug_sigprint();
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return det(X.get_ref());
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}
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template<typename T1>
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inline
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arma_warn_unused
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typename enable_if2< is_supported_blas_type<typename T1::elem_type>::value, typename T1::elem_type >::result
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det
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(
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const Base<typename T1::elem_type,T1>& X,
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const char* // argument kept only for compatibility with old user code
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)
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{
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arma_extra_debug_sigprint();
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return det(X.get_ref());
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}
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template<typename T>
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arma_inline
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arma_warn_unused
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const typename arma_scalar_only<T>::result &
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det(const T& x)
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{
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return x;
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}
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//! @}
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