atl_axpy.c

基于Blas CLapck的.用过的人知道是干啥的

/*
 *             Automatically Tuned Linear Algebra Software v3.8.0
 *                    (C) Copyright 1999 R. Clint Whaley
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions, and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *   3. The name of the ATLAS group or the names of its contributers may
 *      not be used to endorse or promote products derived from this
 *      software without specific written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ATLAS GROUP OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include "atlas_misc.h"

#ifdef Conj_
void Mjoin(PATL,axpyConj)
/*
 * y <- y + alpha * conj(x);
 */
#else
void Mjoin(PATL,axpy)
/*
 * y <- y + alpha * x;
 */
#endif
   (const int N, const SCALAR alpha, const TYPE *X, const int incX,
    TYPE *Y, const int incY)
{
#ifdef TREAL
   int i;
   if (alpha != ATL_rzero)
   {
      if (alpha == ATL_rone)
      {
         if (incX == 1 && incY == 1)
            for (i=0; i != N; i++) Y[i] += X[i];
         else for (i=N; i; i--, X += incX, Y += incY) *Y += *X;
      }
      else if (incX == 1 && incY == 1)
         #if (defined(ATL_NOMULADD) && ATL_mmnreg >= 25)
            Mjoin(PATL,axpy_x1_y1)(N, alpha, X, 1, Y, 1);
         #else
            for (i=0; i != N; i++) Y[i] += alpha * X[i];
         #endif
      else for (i=N; i; i--, X += incX, Y += incY) *Y += alpha * *X;
   }
#else
   int i;
   const int incx = incX<<1, incy = incY<<1;
   const register TYPE ralpha = *alpha, ialpha = alpha[1];
   #ifdef Conj_
      const register TYPE conjal = -ralpha;
   #else
      #define conjal ralpha
   #endif
   register TYPE rtmp, itmp;

   if (ialpha == ATL_rzero)
   {
      if (ralpha == ATL_rzero) return;
      #ifndef Conj_
         else if (incX == 1 && incY == 1)
            Mjoin(PATLU,axpy)(N<<1, ralpha, X, 1, Y, 1);
      #endif
      else
      {
         for (i=N; i; i--, X += incx, Y += incy)
         {
            *Y += ralpha * *X;
            Y[1] += conjal * X[1];
         }
      }
   }
   else
   {
      #if defined(ATL_NOMULADD) && ATL_mmnreg >= 26
         if (incX == 1 && incY == 1)
         {
            #ifdef Conj_
               Mjoin(PATL,axpyConj_x1_y1)(N, alpha, X, 1, Y, 1);
            #else
               Mjoin(PATL,axpy_x1_y1)(N, alpha, X, 1, Y, 1);
            #endif
            return;
         }
      #endif
      for (i=N; i; i--, X += incx, Y += incy)
      {
         rtmp = *X;
         itmp = X[1];
         #ifdef Conj_
            *Y += rtmp * ralpha + itmp * ialpha;
            Y[1] += rtmp * ialpha - itmp * ralpha;
         #else
            *Y += rtmp * ralpha - itmp * ialpha;
            Y[1] += itmp * ralpha + rtmp * ialpha;
         #endif
      }
   }
#endif
}