Chris@49: // Copyright (C) 2008-2011 NICTA (www.nicta.com.au)
Chris@49: // Copyright (C) 2008-2011 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 op_inv
Chris@49: //! @{
Chris@49: 
Chris@49: 
Chris@49: //! immediate inverse of a matrix, storing the result in a dense matrix
Chris@49: template<typename eT>
Chris@49: inline
Chris@49: void
Chris@49: op_inv::apply(Mat<eT>& out, const Mat<eT>& A, const bool slow)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   // no need to check for aliasing, due to:
Chris@49:   // - auxlib::inv() copies A to out before inversion
Chris@49:   // - for 2x2 and 3x3 matrices the code is alias safe
Chris@49:   
Chris@49:   bool status = auxlib::inv(out, A, slow);
Chris@49:   
Chris@49:   if(status == false)
Chris@49:     {
Chris@49:     out.reset();
Chris@49:     arma_bad("inv(): matrix appears to be singular");
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! immediate inverse of T1, storing the result in a dense matrix
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: void
Chris@49: op_inv::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   const strip_diagmat<T1> strip(X.m);
Chris@49:   
Chris@49:   if(strip.do_diagmat == true)
Chris@49:     {
Chris@49:     op_inv::apply_diag(out, strip.M);
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     const uword mode = X.aux_uword_a;
Chris@49:     
Chris@49:     const bool status = (mode == 0) ? auxlib::inv(out, X.m) : auxlib::inv(out, X.m, true);
Chris@49:     
Chris@49:     if(status == false)
Chris@49:       {
Chris@49:       out.reset();
Chris@49:       arma_bad("inv(): matrix appears to be singular");
Chris@49:       }
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: void
Chris@49: op_inv::apply_diag(Mat<typename T1::elem_type>& out, const Base<typename T1::elem_type, T1>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const diagmat_proxy_check<T1> A(X.get_ref(), out);
Chris@49:   
Chris@49:   const uword N = A.n_elem;
Chris@49:   
Chris@49:   out.set_size(N,N);
Chris@49:   
Chris@49:   for(uword col=0; col<N; ++col)
Chris@49:     {
Chris@49:     for(uword row=0; row<col; ++row)   { out.at(row,col) = eT(0); }
Chris@49:     
Chris@49:     out.at(col,col) = eT(1) / A[col];
Chris@49:     
Chris@49:     for(uword row=col+1; row<N; ++row) { out.at(row,col) = eT(0); }
Chris@49:     }
Chris@49:   
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! inverse of T1 (triangular matrices)
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: void
Chris@49: op_inv_tr::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv_tr>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   const bool status = auxlib::inv_tr(out, X.m, X.aux_uword_a);
Chris@49:   
Chris@49:   if(status == false)
Chris@49:     {
Chris@49:     out.reset();
Chris@49:     arma_bad("inv(): matrix appears to be singular");
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! inverse of T1 (symmetric positive definite matrices)
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: void
Chris@49: op_inv_sympd::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv_sympd>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   const bool status = auxlib::inv_sympd(out, X.m, X.aux_uword_a);
Chris@49:   
Chris@49:   if(status == false)
Chris@49:     {
Chris@49:     out.reset();
Chris@49:     arma_bad("inv(): matrix appears to be singular");
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}