xref: /petsc/src/mat/impls/aij/mpi/fdmpiaij.c (revision 3acb87959449f26430bfb44c593b059e1dfb39fd)

#define PETSCMAT_DLL

#include "../src/mat/impls/aij/mpi/mpiaij.h"

EXTERN PetscErrorCode CreateColmap_MPIAIJ_Private(Mat);

#undef __FUNCT__
#define __FUNCT__ "MatFDColoringCreate_MPIAIJ"
/*
    This routine is shared by AIJ and BAIJ matrices, since it operators only on the nonzero structure of the elements or blocks.
    This is why it has the ugly code with the MatGetBlockSize()
*/
PetscErrorCode MatFDColoringCreate_MPIAIJ(Mat mat,ISColoring iscoloring,MatFDColoring c)
{
  Mat_MPIAIJ            *aij = (Mat_MPIAIJ*)mat->data;
  PetscErrorCode        ierr;
  PetscMPIInt           size,*ncolsonproc,*disp,nn;
  PetscInt              bs = 1,i,n,nrows,j,k,m,*rows = 0,*A_ci,*A_cj,ncols,col;
  const PetscInt        *is;
  PetscInt              nis = iscoloring->n,nctot,*cols,*B_ci,*B_cj;
  PetscInt              *rowhit,M = mat->rmap->n,cstart = mat->cmap->rstart,cend = mat->cmap->rend,colb;
  PetscInt              *columnsforrow,l;
  IS                    *isa;
  PetscTruth             done,flg;
  ISLocalToGlobalMapping map = mat->mapping;
  PetscInt               *ltog = (map ? map->indices : (PetscInt*) PETSC_NULL) ,ctype=c->ctype;
  PetscTruth             flg1,flg2;

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

  ierr = ISColoringGetIS(iscoloring,PETSC_IGNORE,&isa);CHKERRQ(ierr);

  /* this is ugly way to get blocksize but cannot call MatGetBlockSize() because AIJ can have bs > 1 */
  ierr = PetscTypeCompare((PetscObject)mat,MATSEQBAIJ,&flg1);CHKERRQ(ierr);
  ierr = PetscTypeCompare((PetscObject)mat,MATMPIBAIJ,&flg2);CHKERRQ(ierr);
  if (flg1 || flg2) {
    ierr = MatGetBlockSize(mat,&bs);CHKERRQ(ierr);
  }

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

  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(c,5*nis*sizeof(PetscInt));CHKERRQ(ierr);

  /* Allow access to data structures of local part of matrix */
  if (!aij->colmap) {
    ierr = CreateColmap_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(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(((PetscObject)mat)->comm,&size);CHKERRQ(ierr);
      ierr = PetscMalloc(2*size*sizeof(PetscInt*),&ncolsonproc);CHKERRQ(ierr);
      disp = ncolsonproc + size;

      nn   = PetscMPIIntCast(n);
      ierr = MPI_Allgather(&nn,1,MPI_INT,ncolsonproc,1,MPI_INT,((PetscObject)mat)->comm);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,((PetscObject)mat)->comm);CHKERRQ(ierr);
      ierr = PetscFree(ncolsonproc);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_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 = PetscOptionsGetTruth(PETSC_NULL,"-matfdcoloring_slow",&flg,PETSC_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(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_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(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(((PetscObject)mat)->comm,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, *gtol;
    ierr = PetscMalloc((N+1)*sizeof(PetscInt),&gtol);CHKERRQ(ierr);
    for (i=0; i<N; i++) gtol[i] = -1;
    for (i=0; i<map->n; 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);
  PetscFunctionReturn(0);
}