DistributionBloc.h

Go to the documentation of this file.

#ifndef DISTRIBUTION_BLOC_1D_IS_DEFINED
#define DISTRIBUTION_BLOC_1D_IS_DEFINED

#include "Type.h"

#if defined(__cplusplus)
extern "C" {
#endif  


  // Definition of bloc: all but the last one have the same size. The last bloc size
  //                     can be null !

  // Compute nb block
  static inline unsigned MaxNumberOfBlock(const unsigned glen, const unsigned nbprocs, const unsigned bsz) {
    unsigned nbbloc = (glen + bsz - 1) / bsz;
    return ((nbbloc + nbprocs - 1 ) / nbprocs);
  }

  static inline unsigned NumberOfBlockProc(const unsigned glen, const unsigned nbprocs, const unsigned bsz, const unsigned rank) {
    unsigned nbbloc = (glen + bsz - 1 ) / bsz;
    return (nbbloc / nbprocs) + (rank < (nbbloc % nbprocs ) ) ;
  }

  // Compute the owner of a bloc
  static inline unsigned OwnerBlock(const unsigned bid, const unsigned nbprocs) {
    return bid % nbprocs;
  }

  // Compute BlockSize
  static inline unsigned blockSize(const unsigned glen, const unsigned nbprocs, const ParisBlock_param_t* param) {
    switch(param->type)
      {
      case PARISBLOCK_BLOCK:
   {
     unsigned nbbloc = (glen + param->unitblocksize - 1) / param->unitblocksize;
     return ((nbbloc + nbprocs - 1 ) / nbprocs) * param->unitblocksize;
   }
      case PARISBLOCK_CYCLIC: return 1; break;
      case PARISBLOCK_BLOCKCYCLIC: return param->blocksize; break;
      }
    return 0;
  }

  // Compute the number of element own by the processor of rank rank
  static inline unsigned TotalNumberOfElementProc(const unsigned glen, const unsigned rank, const unsigned nbprocs, const unsigned bsz) {

    unsigned nbblocfull = NumberOfBlockProc(glen, nbprocs, bsz, rank) - 1;
    // Is the last full ?
    unsigned long low = ( nbblocfull * nbprocs + rank ) * bsz;
    unsigned long end = low + bsz;
    unsigned long high = (glen < end ? glen : end);

    return nbblocfull * bsz + ( high - low );

  }

  // Compute the number of elemet of pos bloc
  static inline unsigned BlockNumberOfElementProc(const unsigned glen, const unsigned rank, const unsigned nbprocs, const unsigned bsz,
                    const unsigned pos) {

    unsigned long low = ( pos * nbprocs + rank ) * bsz;
    unsigned long end = low + bsz;
    unsigned long high = (glen < end ? glen : end);

    return ( high - low );

  }

  // Compute the global bounds low & high of the process of rank rank for the local bloc number pos
  static inline void computeBlockBounds(unsigned long *low, unsigned long *high, const unsigned glen, 
               const unsigned rank, const unsigned nbprocs, const unsigned bsz, const unsigned pos) {

    unsigned long start = (pos * nbprocs + rank) * bsz;
    unsigned long end = start + bsz;
    *low =  start;
    *high = ((glen <= end)?glen:end); // min
  }

  // compute the global low bounds of local bloc number pos
  static inline unsigned computeBlockBoundInf(const unsigned bsz, const unsigned rank, const unsigned nbprocs, const unsigned pos) {
    return  ( pos * nbprocs + rank) * bsz;
  }

  static inline unsigned computeBlockBoundSup(const unsigned glen, const unsigned bsz, const unsigned rank,
                     const unsigned nbprocs, const unsigned pos) {
    unsigned tmp = ( pos * nbprocs + rank + 1) * bsz;
    return ((glen <= tmp)?glen:tmp); // min
  }

#if defined(__cplusplus)
}
#endif

#endif