Chris@49: // Copyright (C) 2008-2013 NICTA (www.nicta.com.au)
Chris@49: // Copyright (C) 2008-2013 Conrad Sanderson
Chris@49: // 
Chris@49: // This Source Code Form is subject to the terms of the Mozilla Public
Chris@49: // License, v. 2.0. If a copy of the MPL was not distributed with this
Chris@49: // file, You can obtain one at http://mozilla.org/MPL/2.0/.
Chris@49: 
Chris@49: 
Chris@49: //! \addtogroup fn_det
Chris@49: //! @{
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! determinant of mat
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: arma_warn_unused
Chris@49: typename T1::elem_type
Chris@49: det
Chris@49:   (
Chris@49:   const Base<typename T1::elem_type,T1>& X,
Chris@49:   const bool slow = false,
Chris@49:   const typename arma_blas_type_only<typename T1::elem_type>::result* junk = 0
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(junk);
Chris@49:   
Chris@49:   return auxlib::det(X, slow);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! determinant of diagmat
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: arma_warn_unused
Chris@49: typename T1::elem_type
Chris@49: det
Chris@49:   (
Chris@49:   const Op<T1, op_diagmat>& X,
Chris@49:   const bool slow = false
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(slow);
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const diagmat_proxy<T1> A(X.m);
Chris@49:   
Chris@49:   const uword N = A.n_elem;
Chris@49:   
Chris@49:   eT val1 = eT(1);
Chris@49:   eT val2 = eT(1);
Chris@49:   
Chris@49:   uword i,j;
Chris@49:   for(i=0, j=1; j<N; i+=2, j+=2)
Chris@49:     {
Chris@49:     val1 *= A[i];
Chris@49:     val2 *= A[j];
Chris@49:     }
Chris@49:   
Chris@49:   
Chris@49:   if(i < N)
Chris@49:     {
Chris@49:     val1 *= A[i];
Chris@49:     }
Chris@49:   
Chris@49:   return val1 * val2;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! determinant of a triangular matrix
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: arma_warn_unused
Chris@49: typename T1::elem_type
Chris@49: det
Chris@49:   (
Chris@49:   const Op<T1, op_trimat>& X,
Chris@49:   const bool slow = false
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(slow);
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const Proxy<T1> P(X.m);
Chris@49:   
Chris@49:   const uword N = P.get_n_rows();
Chris@49:   
Chris@49:   arma_debug_check( (N != P.get_n_cols()), "det(): matrix is not square" );
Chris@49:   
Chris@49:   eT val1 = eT(1);
Chris@49:   eT val2 = eT(1);
Chris@49:   
Chris@49:   uword i,j;
Chris@49:   for(i=0, j=1; j<N; i+=2, j+=2)
Chris@49:     {
Chris@49:     val1 *= P.at(i,i);
Chris@49:     val2 *= P.at(j,j);
Chris@49:     }
Chris@49:   
Chris@49:   if(i < N)
Chris@49:     {
Chris@49:     val1 *= P.at(i,i);
Chris@49:     }
Chris@49:   
Chris@49:   return val1 * val2;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! determinant of inv(A), without doing the inverse operation
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: arma_warn_unused
Chris@49: typename T1::elem_type
Chris@49: det
Chris@49:   (
Chris@49:   const Op<T1,op_inv>& in,
Chris@49:   const bool slow = false,
Chris@49:   const typename arma_blas_type_only<typename T1::elem_type>::result* junk = 0
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(junk);
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   eT tmp = det(in.m, slow);
Chris@49:   arma_warn( (tmp == eT(0)), "det(): warning: denominator is zero" );
Chris@49:   
Chris@49:   return eT(1) / tmp;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! determinant of trans(A)
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: arma_warn_unused
Chris@49: typename T1::elem_type
Chris@49: det
Chris@49:   (
Chris@49:   const Op<T1,op_htrans>& in,
Chris@49:   const bool slow = false,
Chris@49:   const typename arma_blas_type_only<typename T1::elem_type>::result* junk1 = 0,
Chris@49:   const typename         arma_not_cx<typename T1::elem_type>::result* junk2 = 0
Chris@49:   )
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   arma_ignore(junk1);
Chris@49:   arma_ignore(junk2);
Chris@49:   
Chris@49:   return auxlib::det(in.m, slow);  // bypass op_htrans
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T>
Chris@49: arma_inline
Chris@49: arma_warn_unused
Chris@49: const typename arma_scalar_only<T>::result &
Chris@49: det(const T& x)
Chris@49:   {
Chris@49:   return x;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}