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:                                                             

 *                                                                      

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 * 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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 * THEORY OF LIABILITY, WHETHER IN CONTRACT,  STRICT LIABILITY,  OR TORT

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

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

 */ 

/*

 * Include files

 */

#include "hpl.h"

#ifdef STDC_HEADERS

int HPL_indxl2g

(

   const int                        IL,

   const int                        INB,

   const int                        NB,

   const int                        PROC,

   const int                        SRCPROC,

   const int                        NPROCS

)

#else

int HPL_indxl2g

( IL, INB, NB, PROC, SRCPROC, NPROCS )

   const int                        IL;

   const int                        INB;

   const int                        NB;

   const int                        PROC;

   const int                        SRCPROC;

   const int                        NPROCS;

#endif

{

/* 

 * Purpose

 * =======

 *

 * HPL_indxl2g computes the global index of a matrix  entry  pointed to

 * by the local index IL of the process indicated by PROC.

 *

 * Arguments

 * =========

 *

 * IL      (input)                       const int

 *         On entry, IL specifies the local  index of the matrix  entry.

 *         IL must be at least zero.

 *

 * INB     (input)                       const int

 *         On entry,  INB  specifies  the size of the first block of the

 *         global matrix. INB must be at least one.

 *

 * NB      (input)                       const int

 *         On entry,  NB specifies the blocking factor used to partition

 *         and distribute the matrix A. NB must be larger than one.

 *

 * PROC    (input)                       const int

 *         On entry, PROC  specifies the coordinate of the process whose

 *         local array row or column is to be determined. PROC  must  be

 *         at least zero and strictly less than NPROCS.

 *

 * SRCPROC (input)                       const int

 *         On entry,  SRCPROC  specifies  the coordinate of the  process

 *         that possesses the first row or column of the matrix. SRCPROC

 *         must be at least zero and strictly less than NPROCS.

 *

 * NPROCS  (input)                       const int

 *         On entry,  NPROCS  specifies the total number of process rows

 *         or columns over which the matrix is distributed.  NPROCS must

 *         be at least one.

 *

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

 */ 

/* ..

 * .. Executable Statements ..

 */

   if( ( SRCPROC == -1 ) || ( NPROCS == 1 ) )

   {

/*

 * The data is not distributed, or there is just one process in this di-

 * mension of the grid.

 */

      return( IL );

   }

   else if( PROC == SRCPROC )

   {

/*

 * If I am SRCPROC, my first block is of size INB

 */

      if( IL < INB )

/*

 * If  IL  belongs to the first block,  the local and global indexes are

 * equal.

 */

         return ( IL );

/*

 * The  number  of  entire  blocks  before  the  one  IL  belongs  to is

 * ( IL - INB ) / NB + 1.  In  the other NPROCS-1 processes,  there  are

 * thus NB*( ( IL-INB )/NB + 1 ) entries,  that are  globally before the

 * global entry corresponding to IL.

 */

      return( ( NPROCS - 1 ) * NB * ( ( IL - INB ) / NB + 1 ) + IL );

   }

   else if( PROC < SRCPROC )

   {

/*

 * Otherwise, the process of coordinate  MOD(SRCPROC+1, NPROCS) owns the

 * second block. Let IPROC = PROC-SRCPROC-1+NPROCS be the number of pro-

 * cesses between this process and  PROC  not  included  when going from

 * left to right on the process line  with  possible wrap around.  These

 * IPROC  processes have one more NB block than the other processes, who

 * own IL / NB blocks of size NB.

 */

      return( NB*( (NPROCS-1)*(IL/NB)+PROC-SRCPROC-1+NPROCS )+IL+INB );

   }

   else

   {

/*

 * Same reasoning as above with IPROC = PROC - SRCPROC - 1.

 */

      return( NB*( (NPROCS-1)*(IL/NB)+PROC-SRCPROC-1        )+IL+INB );

   }

/*

 * End of HPL_indxl2g

 */

}