max@0: // Copyright (C) 2010-2011 NICTA (www.nicta.com.au)
max@0: // Copyright (C) 2010-2011 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 glue_conv
max@0: //! @{
max@0: 
max@0: 
max@0: //! rudimentary implementation of the convolution operation
max@0: 
max@0: template<typename T1, typename T2>
max@0: inline
max@0: void
max@0: glue_conv::apply(Mat<typename T1::elem_type>& out, const Glue<T1,T2,glue_conv>& X)
max@0:   {
max@0:   arma_extra_debug_sigprint();
max@0:   
max@0:   typedef typename T1::elem_type eT;
max@0:   
max@0:   const unwrap_check<T1> A_tmp(X.A, out);
max@0:   const unwrap_check<T2> B_tmp(X.B, out);
max@0:   
max@0:   const Mat<eT>& A = A_tmp.M;
max@0:   const Mat<eT>& B = B_tmp.M;
max@0:   
max@0:   arma_debug_check( ( (A.is_vec() == false) || (B.is_vec() == false) ), "conv(): inputs must be vectors" );
max@0:   
max@0:   
max@0:   const Mat<eT>& h = (A.n_elem <= B.n_elem) ? A : B;
max@0:   const Mat<eT>& x = (A.n_elem <= B.n_elem) ? B : A;
max@0:   
max@0:   
max@0:   const uword   h_n_elem = h.n_elem;
max@0:   const uword   x_n_elem = x.n_elem;
max@0:   const uword out_n_elem = h_n_elem + x_n_elem - 1;
max@0:   
max@0:   
max@0:   if( (h_n_elem == 0) || (x_n_elem == 0) )
max@0:     {
max@0:     out.reset();
max@0:     return;
max@0:     }
max@0:   
max@0:   
max@0:   (A.n_cols == 1) ? out.set_size(out_n_elem, 1) : out.set_size(1, out_n_elem);
max@0:   
max@0:   
max@0:   const eT*   h_mem = h.memptr();
max@0:   const eT*   x_mem = x.memptr();
max@0:         eT* out_mem = out.memptr();
max@0:   
max@0:   
max@0:   for(uword out_i = 0; out_i < (h_n_elem-1); ++out_i)
max@0:     {
max@0:     eT acc = eT(0);
max@0:     
max@0:     uword h_i = out_i;
max@0:     
max@0:     for(uword x_i = 0; x_i <= out_i; ++x_i, --h_i)
max@0:       {
max@0:       acc += h_mem[h_i] * x_mem[x_i];
max@0:       }
max@0:     
max@0:     out_mem[out_i] = acc;
max@0:     }
max@0:   
max@0:   
max@0:   for(uword out_i = h_n_elem-1; out_i < out_n_elem - (h_n_elem-1); ++out_i)
max@0:     {
max@0:     eT acc = eT(0);
max@0:    
max@0:     uword h_i = h_n_elem - 1;
max@0:     
max@0:     for(uword x_i = out_i - h_n_elem + 1; x_i <= out_i; ++x_i, --h_i)
max@0:       {
max@0:       acc += h_mem[h_i] * x_mem[x_i];
max@0:       }
max@0:       
max@0:     out_mem[out_i] = acc;
max@0:     }
max@0:   
max@0:   
max@0:   for(uword out_i = out_n_elem - (h_n_elem-1); out_i < out_n_elem; ++out_i)
max@0:     {
max@0:     eT acc = eT(0);
max@0:     
max@0:     uword h_i = h_n_elem - 1;
max@0:     
max@0:     for(uword x_i = out_i - h_n_elem + 1; x_i < x_n_elem; ++x_i, --h_i)
max@0:       {
max@0:       acc += h_mem[h_i] * x_mem[x_i];
max@0:       }
max@0:     
max@0:     out_mem[out_i] = acc;
max@0:     }
max@0:   
max@0:   
max@0:   }
max@0: 
max@0: 
max@0: 
max@0: //! @}