xref: /petsc/src/mat/utils/matstash.c (revision 2d5177cd23237a9dae1ff2f970f2ff0cd97d6158)

#ifndef lint
static char vcid[] = "$Id: gcreate.c,v 1.84 1996/04/12 23:41:27 curfman Exp $";
#endif

#include "src/vec/vecimpl.h"
#include "matimpl.h"

#define CHUNCKSIZE   5000
/*
   This stash is currently used for all the parallel matrix implementations.
   The stash is where elements of a matrix destined to be stored on other
   processors are kept until matrix assembly is done.

   This is a simple minded stash. Do a linear search to determine if
   in stash, if not add to end.
*/

int StashInitialize_Private(Stash *stash)
{
  stash->nmax  = 0;
  stash->n     = 0;
  stash->array = 0;
  stash->idx   = 0;
  stash->idy   = 0;
  return 0;
}

int StashBuild_Private(Stash *stash)
{
  stash->nmax  = CHUNCKSIZE; /* completely arbitrary number */
  stash->n     = 0;
  stash->array = (Scalar *) PetscMalloc( stash->nmax*(2*sizeof(int) +
                            sizeof(Scalar))); CHKPTRQ(stash->array);
  stash->idx   = (int *) (stash->array + stash->nmax); CHKPTRQ(stash->idx);
  stash->idy   = (int *) (stash->idx + stash->nmax); CHKPTRQ(stash->idy);
  return 0;
}

int StashDestroy_Private(Stash *stash)
{
  stash->nmax = stash->n = 0;
  if (stash->array) {PetscFree(stash->array); stash->array = 0;}
  return 0;
}

int StashInfo_Private(Stash *stash)
{
  PLogInfo(0,"Stash size %d\n",stash->n);
  return 0;
}

/*
    Should do this properly. With a sorted array.
*/
int StashValues_Private(Stash *stash,int row,int n, int *idxn,
                        Scalar *values,InsertMode addv)
{
  int    i, found, *n_idx, *n_idy;  /* int j, N = stash->n, */
  Scalar val, *n_array;

  for ( i=0; i<n; i++ ) {
    found = 0;
    val = *values++;
/*
   Removed search!  Now much faster assembly.

    for ( j=0; j<N; j++ ) {
      if ( stash->idx[j] == row && stash->idy[j] == idxn[i]) {

        if (addv == ADD_VALUES) stash->array[j] += val;
        else stash->array[j] = val;
        found = 1;
        break;
      }
    }
*/
    if (!found) { /* not found so add to end */
      if ( stash->n == stash->nmax ) {
        /* allocate a larger stash */
        n_array = (Scalar *) PetscMalloc( (stash->nmax + CHUNCKSIZE)*(
                                     2*sizeof(int)+sizeof(Scalar)));CHKPTRQ(n_array);
        n_idx = (int *) (n_array + stash->nmax + CHUNCKSIZE);
        n_idy = (int *) (n_idx + stash->nmax + CHUNCKSIZE);
        PetscMemcpy(n_array,stash->array,stash->nmax*sizeof(Scalar));
        PetscMemcpy(n_idx,stash->idx,stash->nmax*sizeof(int));
        PetscMemcpy(n_idy,stash->idy,stash->nmax*sizeof(int));
        if (stash->array) PetscFree(stash->array);
        stash->array = n_array; stash->idx = n_idx; stash->idy = n_idy;
        stash->nmax += CHUNCKSIZE;
      }
      stash->array[stash->n] = val;
      stash->idx[stash->n]   = row;
      stash->idy[stash->n++] = idxn[i];
    }
  }
  return 0;
}