Chris@49: // Copyright (C) 2010-2013 NICTA (www.nicta.com.au)
Chris@49: // Copyright (C) 2010-2013 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 glue_conv
Chris@49: //! @{
Chris@49: 
Chris@49: 
Chris@49: //! rudimentary implementation of the convolution operation
Chris@49: 
Chris@49: template<typename T1, typename T2>
Chris@49: inline
Chris@49: void
Chris@49: glue_conv::apply(Mat<typename T1::elem_type>& out, const Glue<T1,T2,glue_conv>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const unwrap_check<T1> A_tmp(X.A, out);
Chris@49:   const unwrap_check<T2> B_tmp(X.B, out);
Chris@49:   
Chris@49:   const Mat<eT>& A = A_tmp.M;
Chris@49:   const Mat<eT>& B = B_tmp.M;
Chris@49:   
Chris@49:   arma_debug_check
Chris@49:     (
Chris@49:     ( ((A.is_vec() == false) && (A.is_empty() == false)) || ((B.is_vec() == false) && (B.is_empty() == false)) ),
Chris@49:     "conv(): given object is not a vector"
Chris@49:     );
Chris@49:   
Chris@49:   
Chris@49:   const Mat<eT>& h = (A.n_elem <= B.n_elem) ? A : B;
Chris@49:   const Mat<eT>& x = (A.n_elem <= B.n_elem) ? B : A;
Chris@49:   
Chris@49:   
Chris@49:   const uword   h_n_elem = h.n_elem;
Chris@49:   const uword   x_n_elem = x.n_elem;
Chris@49:   const uword out_n_elem = h_n_elem + x_n_elem - 1;
Chris@49:   
Chris@49:   
Chris@49:   if( (h_n_elem == 0) || (x_n_elem == 0) )
Chris@49:     {
Chris@49:     out.reset();
Chris@49:     return;
Chris@49:     }
Chris@49:   
Chris@49:   
Chris@49:   (A.n_cols == 1) ? out.set_size(out_n_elem, 1) : out.set_size(1, out_n_elem);
Chris@49:   
Chris@49:   
Chris@49:   const eT*   h_mem = h.memptr();
Chris@49:   const eT*   x_mem = x.memptr();
Chris@49:         eT* out_mem = out.memptr();
Chris@49:   
Chris@49:   
Chris@49:   for(uword out_i = 0; out_i < (h_n_elem-1); ++out_i)
Chris@49:     {
Chris@49:     eT acc = eT(0);
Chris@49:     
Chris@49:     uword h_i = out_i;
Chris@49:     
Chris@49:     for(uword x_i = 0; x_i <= out_i; ++x_i, --h_i)
Chris@49:       {
Chris@49:       acc += h_mem[h_i] * x_mem[x_i];
Chris@49:       }
Chris@49:     
Chris@49:     out_mem[out_i] = acc;
Chris@49:     }
Chris@49:   
Chris@49:   
Chris@49:   for(uword out_i = h_n_elem-1; out_i < out_n_elem - (h_n_elem-1); ++out_i)
Chris@49:     {
Chris@49:     eT acc = eT(0);
Chris@49:    
Chris@49:     uword h_i = h_n_elem - 1;
Chris@49:     
Chris@49:     for(uword x_i = out_i - h_n_elem + 1; x_i <= out_i; ++x_i, --h_i)
Chris@49:       {
Chris@49:       acc += h_mem[h_i] * x_mem[x_i];
Chris@49:       }
Chris@49:       
Chris@49:     out_mem[out_i] = acc;
Chris@49:     }
Chris@49:   
Chris@49:   
Chris@49:   for(uword out_i = out_n_elem - (h_n_elem-1); out_i < out_n_elem; ++out_i)
Chris@49:     {
Chris@49:     eT acc = eT(0);
Chris@49:     
Chris@49:     uword h_i = h_n_elem - 1;
Chris@49:     
Chris@49:     for(uword x_i = out_i - h_n_elem + 1; x_i < x_n_elem; ++x_i, --h_i)
Chris@49:       {
Chris@49:       acc += h_mem[h_i] * x_mem[x_i];
Chris@49:       }
Chris@49:     
Chris@49:     out_mem[out_i] = acc;
Chris@49:     }
Chris@49:   
Chris@49:   
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}