atl_srefgbmv.c

基于Blas CLapck的.用过的人知道是干啥的

/* ---------------------------------------------------------------------
 *
 * -- Automatically Tuned Linear Algebra Software (ATLAS)
 *    (C) Copyright 2000 All Rights Reserved
 *
 * -- ATLAS routine -- Version 3.2 -- December 25, 2000
 *
 * Author         : Antoine P. Petitet
 * Originally developed at the University of Tennessee,
 * Innovative Computing Laboratory, Knoxville TN, 37996-1301, USA.
 *
 * ---------------------------------------------------------------------
 *
 * -- Copyright notice and Licensing terms:
 *
 *  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 distri-
 *    bution.
 * 3. The name of the University,  the ATLAS group,  or the names of its
 *    contributors  may not be used to endorse or promote products deri-
 *    ved from this software without specific written permission.
 *
 * -- Disclaimer:
 *
 * 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 UNIVERSITY
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,  INDIRECT, INCIDENTAL, SPE-
 * CIAL, 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 THEO-
 * RY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT  (IN-
 * CLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ---------------------------------------------------------------------
 */
/*
 * Include files
 */
#include "atlas_refmisc.h"
#include "atlas_reflvl2.h"
#include "atlas_reflevel2.h"

void ATL_srefgbmv
(
   const enum ATLAS_TRANS     TRANS,
   const int                  M,
   const int                  N,
   const int                  KL,
   const int                  KU,
   const float                ALPHA,
   const float                * A,
   const int                  LDA,
   const float                * X,
   const int                  INCX,
   const float                BETA,
   float                      * Y,
   const int                  INCY
)
{
/*
 * Purpose
 * =======
 *
 * ATL_srefgbmv performs one of the matrix-vector operations
 *
 *    y := alpha * op( A ) * x + beta * y,
 *
 * where op( X ) is one of
 *
 *    op( X ) = X   or   op( X ) = X'.
 *
 * where  alpha and beta are scalars, x and y are vectors and op( A ) is
 * an m by n band matrix, with kl sub-diagonals and ku super-diagonals.
 *
 * Arguments
 * =========
 *
 * TRANS   (input)                       const enum ATLAS_TRANS
 *         On entry,  TRANS  specifies the  operation to be performed as
 *         follows:
 *
 *            TRANS = AtlasNoTrans    y := alpha*A *x + beta*y,
 *
 *            TRANS = AtlasConj       y := alpha*A *x + beta*y,
 *
 *            TRANS = AtlasTrans      y := alpha*A'*x + beta*y,
 *
 *            TRANS = AtlasConjTrans  y := alpha*A'*x + beta*y.
 *
 *         Unchanged on exit.
 *
 * M       (input)                       const int
 *         On entry,  M  specifies  the number of rows of  the matrix  A
 *         when TRANS = AtlasNoTrans or TRANS = AtlasConj,  and the num-
 *         ber of columns of the matrix  A otherwise. M must be at least
 *         zero. Unchanged on exit.
 *
 * N       (input)                       const int
 *         On entry, N  specifies  the number of columns of the matrix A
 *         when TRANS = AtlasNoTrans or TRANS = AtlasConj,  and the num-
 *         ber of rows of the matrix A otherwise. N must be at least ze-
 *         ro. Unchanged on exit.
 *
 * KL      (input)                       const int
 *         On entry, KL specifies the number of sub-diagonals of the ma-
 *         trix A. KL must satisfy 0 <= KL. Unchanged on exit.
 *
 * KU      (input)                       const int
 *         On entry, KU specifies the number of  super-diagonals of  the
 *         matrix A. KU must satisfy  0 <= KU. Unchanged on exit.
 *
 * ALPHA   (input)                       const float
 *         On entry, ALPHA specifies the scalar alpha.   When  ALPHA  is
 *         supplied as zero then  A and X  need not be set on input. Un-
 *         changed on exit.
 *
 * A       (input)                       const float *
 *         On entry,  A  points  to an array of size equal to or greater
 *         than   LDA * ka * sizeof(   float   ),  where  ka is  n  when
 *         TRANS = AtlasNotrans or TRANS = AtlasConj, and  m  otherwise.
 *         Before entry, the  leading ( kl + ku + 1 ) by ka  part of the
 *         array  A  must contain the matrix of  coefficients,  supplied
 *         column by column,  with the leading diagonal of the matrix in
 *         row ku of the array, the first super-diagonal starting at po-
 *         sition 1 in row ku-1,  the first sub-diagonal starting at po-
 *         sition 0 in row ku+1, and so on. Elements in the array A that
 *         do not correspond to elements in the band matrix (such as the
 *         top left ku by ku triangle) are not referenced.  Unchanged on
 *         exit.
 *
 *         The  following  program segment will transfer a real band ma-
 *         trix from conventional full matrix storage to band storage:
 *
 *            for( j = 0; j < n; j++ )
 *            {
 *               k  = ku - j; i1 = ( m > j + kl + 1 ? j + kl + 1 : m );
 *               for( i = ( k < 0 ? -k : 0 ); i < i1; i++ )
 *               {
 *                  a[k+i+j*LDA] = matrix( i, j );
 *               }
 *            }
 *
 * LDA     (input)                       const int
 *         On entry, LDA  specifies the leading dimension of A as decla-
 *         red  in  the  calling (sub) program.  LDA  must  be  at least
 *         ( kl + ku + 1 ). Unchanged on exit.
 *
 * X       (input)                       const float *
 *         On entry,  X  points to the  first entry to be accessed of an
 *         incremented array of size equal to or greater than
 *            ( 1 + ( n - 1 ) * abs( INCX ) ) * sizeof(   float   ),
 *         that contains the vector x. Unchanged on exit.
 *
 * INCX    (input)                       const int
 *         On entry, INCX specifies the increment for the elements of X.
 *         INCX must not be zero. Unchanged on exit.
 *
 * BETA    (input)                       const float
 *         On entry,  BETA  specifies the scalar  beta.   When  BETA  is
 *         supplied as zero then Y  need not be set on input.  Unchanged
 *         on exit.
 *
 * Y       (input/output)                float *
 *         On entry,  Y  points to the  first entry to be accessed of an
 *         incremented array of size equal to or greater than
 *            ( 1 + ( m - 1 ) * abs( INCY ) ) * sizeof(   float   ),
 *         that contains the vector y.  Before entry with BETA non-zero,
 *         the incremented array  Y  must contain the vector y. On exit,
 *         Y is overwritten by the updated vector y.
 *
 * INCY    (input)                       const int
 *         On entry, INCY specifies the increment for the elements of Y.
 *         INCY must not be zero. Unchanged on exit.
 *
 * ---------------------------------------------------------------------
 */
/* ..
 * .. Executable Statements ..
 *
 */
   if( ( M == 0 ) || ( N == 0 ) ||
       ( ( ALPHA == ATL_sZERO ) && ( BETA == ATL_sONE  ) ) ) return;

   if( ALPHA == ATL_sZERO ) { Msvscal( M, BETA, Y, INCY ); return; }

   if( ( TRANS == AtlasNoTrans ) || ( TRANS == AtlasConj ) )
   {
      ATL_srefgbmvN( M, N, KL, KU, ALPHA, A, LDA, X, INCX, BETA, Y, INCY );
   }
   else
   {
      ATL_srefgbmvT( M, N, KL, KU, ALPHA, A, LDA, X, INCX, BETA, Y, INCY );
   }
/*
 * End of ATL_srefgbmv
 */
}