gemv_arma< do_trans_A, use_alpha, use_beta > Class Template Reference [Gemv]

//! Partial emulation of ATLAS/BLAS gemv(). //! 'y' is assumed to have been set to the correct size (i.e. taking into account the transpose) More...

#include <gemv.hpp>

List of all members.

Static Public Member Functions
template<typename eT >
static arma_hot void	apply (eT *y, const Mat< eT > &A, const eT *x, const eT alpha=eT(1), const eT beta=eT(0))

---

Detailed Description

template<const bool do_trans_A = false, const bool use_alpha = false, const bool use_beta = false>
class gemv_arma< do_trans_A, use_alpha, use_beta >

//! Partial emulation of ATLAS/BLAS gemv(). //! 'y' is assumed to have been set to the correct size (i.e. taking into account the transpose)

Definition at line 27 of file gemv.hpp.

---

Member Function Documentation

template<const bool do_trans_A = false, const bool use_alpha = false, const bool use_beta = false>

template<typename eT >

static arma_hot void gemv_arma< do_trans_A, use_alpha, use_beta >::apply	(	eT *	y,
		const Mat< eT > &	A,
		const eT *	x,
		const eT	alpha = eT(1),
		const eT	beta = eT(0)
	)			[inline, static]

Definition at line 36 of file gemv.hpp.

References Mat< eT >::at(), Mat< eT >::colptr(), Mat< eT >::n_cols, and Mat< eT >::n_rows.

    {
    arma_extra_debug_sigprint();
    
    const u32 A_n_rows = A.n_rows;
    const u32 A_n_cols = A.n_cols;
    
    if(do_trans_A == false)
      {
      for(u32 row=0; row < A_n_rows; ++row)
        {
        
        eT acc = eT(0);
        for(u32 col=0; col < A_n_cols; ++col)
          {
          acc += A.at(row,col) * x[col];
          }
          
        if( (use_alpha == false) && (use_beta == false) )
          {
          y[row] = acc;
          }
        else
        if( (use_alpha == true) && (use_beta == false) )
          {
          y[row] = alpha * acc;
          }
        else
        if( (use_alpha == false) && (use_beta == true) )
          {
          y[row] = acc + beta*y[row];
          }
        else
        if( (use_alpha == true) && (use_beta == true) )
          {
          y[row] = alpha*acc + beta*y[row];
          }
        }
      }
    else
    if(do_trans_A == true)
      {
      for(u32 col=0; col < A_n_cols; ++col)
        {
        // col is interpreted as row when storing the results in 'y'
        
        const eT* A_coldata = A.colptr(col);
        
        eT acc = eT(0);
        for(u32 row=0; row < A_n_rows; ++row)
          {
          acc += A_coldata[row] * x[row];
          }
      
        if( (use_alpha == false) && (use_beta == false) )
          {
          y[col] = acc;
          }
        else
        if( (use_alpha == true) && (use_beta == false) )
          {
          y[col] = alpha * acc;
          }
        else
        if( (use_alpha == false) && (use_beta == true) )
          {
          y[col] = acc + beta*y[col];
          }
        else
        if( (use_alpha == true) && (use_beta == true) )
          {
          y[col] = alpha*acc + beta*y[col];
          }
        
        }
      }
    }