max@0: // Copyright (C) 2008-2011 NICTA (www.nicta.com.au)
max@0: // Copyright (C) 2008-2011 Conrad Sanderson
max@0: // 
max@0: // This file is part of the Armadillo C++ library.
max@0: // It is provided without any warranty of fitness
max@0: // for any purpose. You can redistribute this file
max@0: // and/or modify it under the terms of the GNU
max@0: // Lesser General Public License (LGPL) as published
max@0: // by the Free Software Foundation, either version 3
max@0: // of the License or (at your option) any later version.
max@0: // (see http://www.opensource.org/licenses for more info)
max@0: 
max@0: 
max@0: //! \addtogroup op_inv
max@0: //! @{
max@0: 
max@0: 
max@0: //! immediate inverse of a matrix, storing the result in a dense matrix
max@0: template<typename eT>
max@0: inline
max@0: void
max@0: op_inv::apply(Mat<eT>& out, const Mat<eT>& A, const bool slow)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   // no need to check for aliasing, due to:
max@0:   // - auxlib::inv() copies A to out before inversion
max@0:   // - for 2x2 and 3x3 matrices the code is alias safe
max@0:   
max@0:   bool status = auxlib::inv(out, A, slow);
max@0:   
max@0:   if(status == false)
max@0:     {
max@0:     out.reset();
max@0:     arma_bad("inv(): matrix appears to be singular");
max@0:     }
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! immediate inverse of T1, storing the result in a dense matrix
max@0: template<typename T1>
max@0: inline
max@0: void
max@0: op_inv::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv>& X)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   typedef typename T1::elem_type eT;
max@0:   
max@0:   const strip_diagmat<T1> strip(X.m);
max@0:   
max@0:   if(strip.do_diagmat == true)
max@0:     {
max@0:     op_inv::apply_diag(out, strip.M);
max@0:     }
max@0:   else
max@0:     {
max@0:     const uword mode = X.aux_uword_a;
max@0:     
max@0:     const bool status = (mode == 0) ? auxlib::inv(out, X.m) : auxlib::inv(out, X.m, true);
max@0:     
max@0:     if(status == false)
max@0:       {
max@0:       out.reset();
max@0:       arma_bad("inv(): matrix appears to be singular");
max@0:       }
max@0:     }
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: template<typename T1>
max@0: inline
max@0: void
max@0: op_inv::apply_diag(Mat<typename T1::elem_type>& out, const Base<typename T1::elem_type, T1>& X)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   typedef typename T1::elem_type eT;
max@0:   
max@0:   const diagmat_proxy_check<T1> A(X.get_ref(), out);
max@0:   
max@0:   const uword N = A.n_elem;
max@0:   
max@0:   out.set_size(N,N);
max@0:   
max@0:   for(uword col=0; col<N; ++col)
max@0:     {
max@0:     for(uword row=0; row<col; ++row)   { out.at(row,col) = eT(0); }
max@0:     
max@0:     out.at(col,col) = eT(1) / A[col];
max@0:     
max@0:     for(uword row=col+1; row<N; ++row) { out.at(row,col) = eT(0); }
max@0:     }
max@0:   
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! inverse of T1 (triangular matrices)
max@0: template<typename T1>
max@0: inline
max@0: void
max@0: op_inv_tr::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv_tr>& X)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   const bool status = auxlib::inv_tr(out, X.m, X.aux_uword_a);
max@0:   
max@0:   if(status == false)
max@0:     {
max@0:     out.reset();
max@0:     arma_bad("inv(): matrix appears to be singular");
max@0:     }
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! inverse of T1 (symmetric positive definite matrices)
max@0: template<typename T1>
max@0: inline
max@0: void
max@0: op_inv_sympd::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_inv_sympd>& X)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   const bool status = auxlib::inv_sympd(out, X.m, X.aux_uword_a);
max@0:   
max@0:   if(status == false)
max@0:     {
max@0:     out.reset();
max@0:     arma_bad("inv(): matrix appears to be singular");
max@0:     }
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! @}