xref: /petsc/src/mat/impls/aij/mpi/fdmpiaij.c (revision 3bb1ff401821b9e2ae019d3e61bc8ab4bd4e59d5)

#include <../src/mat/impls/aij/mpi/mpiaij.h>

extern PetscErrorCode MatCreateColmap_MPIAIJ_Private(Mat);

#undef __FUNCT__
#define __FUNCT__ "MatFDColoringCreate_MPIAIJ"
PetscErrorCode MatFDColoringCreate_MPIAIJ(Mat mat,ISColoring iscoloring,MatFDColoring c)
{
  Mat_MPIAIJ             *aij = (Mat_MPIAIJ*)mat->data;
  PetscErrorCode         ierr;
  PetscMPIInt            size,*ncolsonproc,*disp,nn;
  PetscInt               i,n,nrows,j,k,m,ncols,col;
  const PetscInt         *is,*A_ci,*A_cj,*B_ci,*B_cj,*rows = 0,*ltog;
  PetscInt               nis = iscoloring->n,nctot,*cols;
  PetscInt               *rowhit,M,cstart,cend,colb;
  PetscInt               *columnsforrow,l;
  IS                     *isa;
  PetscBool              done,flg;
  ISLocalToGlobalMapping map   = mat->cmap->mapping;
  PetscInt               ctype=c->ctype;

  PetscFunctionBegin;
  if (!mat->assembled) SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_ARG_WRONGSTATE,"Matrix must be assembled first; MatAssemblyBegin/End();");
  if (ctype == IS_COLORING_GHOSTED && !map) SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_ARG_INCOMP,"When using ghosted differencing matrix must have local to global mapping provided with MatSetLocalToGlobalMapping");

  if (map) {ierr = ISLocalToGlobalMappingGetIndices(map,&ltog);CHKERRQ(ierr);}
  else     ltog = NULL;
  ierr = ISColoringGetIS(iscoloring,PETSC_IGNORE,&isa);CHKERRQ(ierr);

  M         = mat->rmap->n;
  cstart    = mat->cmap->rstart;
  cend      = mat->cmap->rend;
  c->M      = mat->rmap->N;         /* set the global rows and columns and local rows */
  c->N      = mat->cmap->N;
  c->m      = mat->rmap->n;
  c->rstart = mat->rmap->rstart;

  c->ncolors = nis;
  ierr       = PetscMalloc(nis*sizeof(PetscInt),&c->ncolumns);CHKERRQ(ierr);
  ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->columns);CHKERRQ(ierr);
  ierr       = PetscMalloc(nis*sizeof(PetscInt),&c->nrows);CHKERRQ(ierr);
  ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->rows);CHKERRQ(ierr);
  ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->columnsforrow);CHKERRQ(ierr);
  ierr       = PetscLogObjectMemory((PetscObject)c,5*nis*sizeof(PetscInt));CHKERRQ(ierr);

  /* Allow access to data structures of local part of matrix */
  if (!aij->colmap) {
    ierr = MatCreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
  }
  ierr = MatGetColumnIJ(aij->A,0,PETSC_FALSE,PETSC_FALSE,&ncols,&A_ci,&A_cj,&done);CHKERRQ(ierr);
  ierr = MatGetColumnIJ(aij->B,0,PETSC_FALSE,PETSC_FALSE,&ncols,&B_ci,&B_cj,&done);CHKERRQ(ierr);

  ierr = PetscMalloc((M+1)*sizeof(PetscInt),&rowhit);CHKERRQ(ierr);
  ierr = PetscMalloc((M+1)*sizeof(PetscInt),&columnsforrow);CHKERRQ(ierr);

  for (i=0; i<nis; i++) {
    ierr = ISGetLocalSize(isa[i],&n);CHKERRQ(ierr);
    ierr = ISGetIndices(isa[i],&is);CHKERRQ(ierr);

    c->ncolumns[i] = n;
    if (n) {
      ierr = PetscMalloc(n*sizeof(PetscInt),&c->columns[i]);CHKERRQ(ierr);
      ierr = PetscLogObjectMemory((PetscObject)c,n*sizeof(PetscInt));CHKERRQ(ierr);
      ierr = PetscMemcpy(c->columns[i],is,n*sizeof(PetscInt));CHKERRQ(ierr);
    } else {
      c->columns[i] = 0;
    }

    if (ctype == IS_COLORING_GLOBAL) {
      /* Determine the total (parallel) number of columns of this color */
      ierr = MPI_Comm_size(PetscObjectComm((PetscObject)mat),&size);CHKERRQ(ierr);
      ierr = PetscMalloc2(size,PetscMPIInt,&ncolsonproc,size,PetscMPIInt,&disp);CHKERRQ(ierr);

      ierr  = PetscMPIIntCast(n,&nn);CHKERRQ(ierr);
      ierr  = MPI_Allgather(&nn,1,MPI_INT,ncolsonproc,1,MPI_INT,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
      nctot = 0; for (j=0; j<size; j++) nctot += ncolsonproc[j];
      if (!nctot) {
        ierr = PetscInfo(mat,"Coloring of matrix has some unneeded colors with no corresponding rows\n");CHKERRQ(ierr);
      }

      disp[0] = 0;
      for (j=1; j<size; j++) {
        disp[j] = disp[j-1] + ncolsonproc[j-1];
      }

      /* Get complete list of columns for color on each processor */
      ierr = PetscMalloc((nctot+1)*sizeof(PetscInt),&cols);CHKERRQ(ierr);
      ierr = MPI_Allgatherv((void*)is,n,MPIU_INT,cols,ncolsonproc,disp,MPIU_INT,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
      ierr = PetscFree2(ncolsonproc,disp);CHKERRQ(ierr);
    } else if (ctype == IS_COLORING_GHOSTED) {
      /* Determine local number of columns of this color on this process, including ghost points */
      nctot = n;
      ierr  = PetscMalloc((nctot+1)*sizeof(PetscInt),&cols);CHKERRQ(ierr);
      ierr  = PetscMemcpy(cols,is,n*sizeof(PetscInt));CHKERRQ(ierr);
    } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not provided for this MatFDColoring type");

    /*
       Mark all rows affect by these columns
    */
    /* Temporary option to allow for debugging/testing */
    flg  = PETSC_FALSE;
    ierr = PetscOptionsGetBool(NULL,"-matfdcoloring_slow",&flg,NULL);CHKERRQ(ierr);
    if (!flg) { /*-----------------------------------------------------------------------------*/
      /* crude, fast version */
      ierr = PetscMemzero(rowhit,M*sizeof(PetscInt));CHKERRQ(ierr);
      /* loop over columns*/
      for (j=0; j<nctot; j++) {
        if (ctype == IS_COLORING_GHOSTED) {
          col = ltog[cols[j]];
        } else {
          col = cols[j];
        }
        if (col >= cstart && col < cend) {
          /* column is in diagonal block of matrix */
          rows = A_cj + A_ci[col-cstart];
          m    = A_ci[col-cstart+1] - A_ci[col-cstart];
        } else {
#if defined(PETSC_USE_CTABLE)
          ierr = PetscTableFind(aij->colmap,col+1,&colb);CHKERRQ(ierr);
          colb--;
#else
          colb = aij->colmap[col] - 1;
#endif
          if (colb == -1) {
            m = 0;
          } else {
            rows = B_cj + B_ci[colb];
            m    = B_ci[colb+1] - B_ci[colb];
          }
        }
        /* loop over columns marking them in rowhit */
        for (k=0; k<m; k++) {
          rowhit[*rows++] = col + 1;
        }
      }

      /* count the number of hits */
      nrows = 0;
      for (j=0; j<M; j++) {
        if (rowhit[j]) nrows++;
      }
      c->nrows[i] = nrows;
      ierr        = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->rows[i]);CHKERRQ(ierr);
      ierr        = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->columnsforrow[i]);CHKERRQ(ierr);
      ierr        = PetscLogObjectMemory((PetscObject)c,2*(nrows+1)*sizeof(PetscInt));CHKERRQ(ierr);
      nrows       = 0;
      for (j=0; j<M; j++) {
        if (rowhit[j]) {
          c->rows[i][nrows]          = j;
          c->columnsforrow[i][nrows] = rowhit[j] - 1;
          nrows++;
        }
      }
    } else { /*-------------------------------------------------------------------------------*/
      /* slow version, using rowhit as a linked list */
      PetscInt currentcol,fm,mfm;
      rowhit[M] = M;
      nrows     = 0;
      /* loop over columns*/
      for (j=0; j<nctot; j++) {
        if (ctype == IS_COLORING_GHOSTED) {
          col = ltog[cols[j]];
        } else {
          col = cols[j];
        }
        if (col >= cstart && col < cend) {
          /* column is in diagonal block of matrix */
          rows = A_cj + A_ci[col-cstart];
          m    = A_ci[col-cstart+1] - A_ci[col-cstart];
        } else {
#if defined(PETSC_USE_CTABLE)
          ierr = PetscTableFind(aij->colmap,col+1,&colb);CHKERRQ(ierr);
          colb--;
#else
          colb = aij->colmap[col] - 1;
#endif
          if (colb == -1) {
            m = 0;
          } else {
            rows = B_cj + B_ci[colb];
            m    = B_ci[colb+1] - B_ci[colb];
          }
        }

        /* loop over columns marking them in rowhit */
        fm = M;    /* fm points to first entry in linked list */
        for (k=0; k<m; k++) {
          currentcol = *rows++;
          /* is it already in the list? */
          do {
            mfm = fm;
            fm  = rowhit[fm];
          } while (fm < currentcol);
          /* not in list so add it */
          if (fm != currentcol) {
            nrows++;
            columnsforrow[currentcol] = col;
            /* next three lines insert new entry into linked list */
            rowhit[mfm]        = currentcol;
            rowhit[currentcol] = fm;
            fm                 = currentcol;
            /* fm points to present position in list since we know the columns are sorted */
          } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Invalid coloring of matrix detected");
        }
      }
      c->nrows[i] = nrows;

      ierr = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->rows[i]);CHKERRQ(ierr);
      ierr = PetscMalloc((nrows+1)*sizeof(PetscInt),&c->columnsforrow[i]);CHKERRQ(ierr);
      ierr = PetscLogObjectMemory((PetscObject)c,(nrows+1)*sizeof(PetscInt));CHKERRQ(ierr);
      /* now store the linked list of rows into c->rows[i] */
      nrows = 0;
      fm    = rowhit[M];
      do {
        c->rows[i][nrows]            = fm;
        c->columnsforrow[i][nrows++] = columnsforrow[fm];
        fm                           = rowhit[fm];
      } while (fm < M);
    } /* ---------------------------------------------------------------------------------------*/
    ierr = PetscFree(cols);CHKERRQ(ierr);
  }

  /* Optimize by adding the vscale, and scaleforrow[][] fields */
  /*
       vscale will contain the "diagonal" on processor scalings followed by the off processor
  */
  if (ctype == IS_COLORING_GLOBAL) {
    ierr = VecCreateGhost(PetscObjectComm((PetscObject)mat),aij->A->rmap->n,PETSC_DETERMINE,aij->B->cmap->n,aij->garray,&c->vscale);CHKERRQ(ierr);
    ierr = PetscMalloc(c->ncolors*sizeof(PetscInt*),&c->vscaleforrow);CHKERRQ(ierr);
    for (k=0; k<c->ncolors; k++) {
      ierr = PetscMalloc((c->nrows[k]+1)*sizeof(PetscInt),&c->vscaleforrow[k]);CHKERRQ(ierr);
      for (l=0; l<c->nrows[k]; l++) {
        col = c->columnsforrow[k][l];
        if (col >= cstart && col < cend) {
          /* column is in diagonal block of matrix */
          colb = col - cstart;
        } else {
          /* column  is in "off-processor" part */
#if defined(PETSC_USE_CTABLE)
          ierr = PetscTableFind(aij->colmap,col+1,&colb);CHKERRQ(ierr);
          colb--;
#else
          colb = aij->colmap[col] - 1;
#endif
          colb += cend - cstart;
        }
        c->vscaleforrow[k][l] = colb;
      }
    }
  } else if (ctype == IS_COLORING_GHOSTED) {
    /* Get gtol mapping */
    PetscInt N = mat->cmap->N,nlocal,*gtol;
    ierr = PetscMalloc((N+1)*sizeof(PetscInt),&gtol);CHKERRQ(ierr);
    for (i=0; i<N; i++) gtol[i] = -1;
    ierr = ISLocalToGlobalMappingGetSize(map,&nlocal);CHKERRQ(ierr);
    for (i=0; i<nlocal; i++) gtol[ltog[i]] = i;

    c->vscale = 0; /* will be created in MatFDColoringApply() */
    ierr      = PetscMalloc(c->ncolors*sizeof(PetscInt*),&c->vscaleforrow);CHKERRQ(ierr);
    for (k=0; k<c->ncolors; k++) {
      ierr = PetscMalloc((c->nrows[k]+1)*sizeof(PetscInt),&c->vscaleforrow[k]);CHKERRQ(ierr);
      for (l=0; l<c->nrows[k]; l++) {
        col = c->columnsforrow[k][l];      /* global column index */

        c->vscaleforrow[k][l] = gtol[col]; /* local column index */
      }
    }
    ierr = PetscFree(gtol);CHKERRQ(ierr);
  }
  ierr = ISColoringRestoreIS(iscoloring,&isa);CHKERRQ(ierr);

  ierr = PetscFree(rowhit);CHKERRQ(ierr);
  ierr = PetscFree(columnsforrow);CHKERRQ(ierr);
  ierr = MatRestoreColumnIJ(aij->A,0,PETSC_FALSE,PETSC_FALSE,&ncols,&A_ci,&A_cj,&done);CHKERRQ(ierr);
  ierr = MatRestoreColumnIJ(aij->B,0,PETSC_FALSE,PETSC_FALSE,&ncols,&B_ci,&B_cj,&done);CHKERRQ(ierr);
  if (map) {ierr = ISLocalToGlobalMappingRestoreIndices(map,&ltog);CHKERRQ(ierr);}
  PetscFunctionReturn(0);
}