Centre Blaise Pascal » HPL sur GPU

/* 

 * -- High Performance Computing Linpack Benchmark (HPL)                

 *    HPL - 2.0 - September 10, 2008                          

 *    Antoine P. Petitet                                                

 *    University of Tennessee, Knoxville                                

 *    Innovative Computing Laboratory                                 

 *    (C) Copyright 2000-2008 All Rights Reserved                       

 *                                                                      

 * -- 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 distribution. 

 *                                                                      

 * 3. All  advertising  materials  mentioning  features  or  use of this

 * software must display the following acknowledgement:                 

 * This  product  includes  software  developed  at  the  University  of

 * Tennessee, Knoxville, Innovative Computing Laboratory.             

 *                                                                      

 * 4. The name of the  University,  the name of the  Laboratory,  or the

 * names  of  its  contributors  may  not  be used to endorse or promote

 * products  derived   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,

 * SPECIAL,  EXEMPLARY,  OR  CONSEQUENTIAL DAMAGES  (INCLUDING,  BUT NOT

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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 * ---------------------------------------------------------------------

 */ 

/*

 * Include files

 */

#include "hpl.h"

#ifdef STDC_HEADERS

void HPL_dlocmax

(

   HPL_T_panel *                    PANEL,

   const int                        N,

   const int                        II,

   const int                        JJ,

   double *                         WORK

)

#else

void HPL_dlocmax

( PANEL, N, II, JJ, WORK )

   HPL_T_panel *                    PANEL;

   const int                        N;

   const int                        II;

   const int                        JJ;

   double *                         WORK;

#endif

{

/* 

 * Purpose

 * =======

 *

 * HPL_dlocmax finds  the maximum entry in the current column  and packs

 * the useful information in  WORK[0:3].  On exit,  WORK[0] contains the

 * local maximum  absolute value  scalar,  WORK[1] is the  corresponding

 * local row index,  WORK[2]  is the corresponding global row index, and

 * WORK[3] is the coordinate of the process owning this max.  When N  is

 * less than 1, the WORK[0:2] is initialized to zero, and WORK[3] is set

 * to the total number of process rows.

 *

 * Arguments

 * =========

 *

 * PANEL   (local input/output)          HPL_T_panel *

 *         On entry,  PANEL  points to the data structure containing the

 *         panel information.

 *

 * N       (local input)                 const int

 *         On entry,  N specifies the local number of rows of the column

 *         of A on which we operate.

 *

 * II      (local input)                 const int

 *         On entry, II  specifies the row offset where the column to be

 *         operated on starts with respect to the panel.

 *

 * JJ      (local input)                 const int

 *         On entry, JJ  specifies the column offset where the column to

 *         be operated on starts with respect to the panel.

 *

 * WORK    (local workspace)             double *

 *         On entry, WORK  is  a workarray of size at least 4.  On exit,

 *         WORK[0] contains  the  local  maximum  absolute value scalar,

 *         WORK[1] contains  the corresponding local row index,  WORK[2]

 *         contains the corresponding global row index, and  WORK[3]  is

 *         the coordinate of process owning this max.

 *

 * ---------------------------------------------------------------------

 */ 

/*

 * .. Local Variables ..

 */

   double                     * A;

   int                        kk, igindx, ilindx, myrow, nb, nprow;

/* ..

 * .. Executable Statements ..

 */

   if( N > 0 )

   {

      A      = Mptr( PANEL->A, II, JJ, PANEL->lda );

      myrow  = PANEL->grid->myrow;

      nprow  = PANEL->grid->nprow;

      nb     = PANEL->nb;

      kk     = PANEL->ii + II + ( ilindx = HPL_idamax( N, A, 1 ) );

      Mindxl2g( igindx, kk, nb, nb, myrow, 0, nprow );

/*

 * WORK[0] := local maximum absolute value scalar,

 * WORK[1] := corresponding local  row index,

 * WORK[2] := corresponding global row index,

 * WORK[3] := coordinate of process owning this max.

 */

      WORK[0] = A[ilindx];         WORK[1] = (double)(ilindx);

      WORK[2] = (double)(igindx);  WORK[3] = (double)(myrow);

   }

   else

   {

/*

 * If I do not have any row of A, then set the coordinate of the process

 * (WORK[3]) owning this "ghost" row,  such that it  will never be used,

 * even if there are only zeros in the current column of A.

 */

      WORK[0] = WORK[1] = WORK[2] = HPL_rzero;

      WORK[3] = (double)(PANEL->grid->nprow);

   }

/*

 * End of HPL_dlocmax

 */

}