Actual source code: fdaij.c

  2: #include <../src/mat/impls/aij/seq/aij.h>

  6: /*
  7:     This routine is shared by AIJ and BAIJ matrices, since it operators only on the nonzero structure of the elements or blocks.
  8:     This is why it has the ugly code with the MatGetBlockSize()
  9: */
 10: PetscErrorCode MatFDColoringCreate_SeqAIJ(Mat mat,ISColoring iscoloring,MatFDColoring c)
 11: {
 13:   PetscInt       i,n,nrows,N,j,k,m,*rows,*ci,*cj,ncols,col;
 14:   const PetscInt *is;
 15:   PetscInt       nis = iscoloring->n,*rowhit,*columnsforrow,l,bs = 1;
 16:   IS             *isa;
 17:   PetscBool      done,flg = PETSC_FALSE;
 18:   PetscBool      flg1,flg2;

 21:   if (!mat->assembled) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Matrix must be assembled by calls to MatAssemblyBegin/End();");

 23:   ISColoringGetIS(iscoloring,PETSC_IGNORE,&isa);
 24:   /* this is ugly way to get blocksize but cannot call MatGetBlockSize() because AIJ can have bs > 1 */
 25:   PetscTypeCompare((PetscObject)mat,MATSEQBAIJ,&flg1);
 26:   PetscTypeCompare((PetscObject)mat,MATMPIBAIJ,&flg2);
 27:   if (flg1 || flg2) {
 28:     MatGetBlockSize(mat,&bs);
 29:   }

 31:   N          = mat->cmap->N/bs;
 32:   c->M       = mat->rmap->N/bs;  /* set total rows, columns and local rows */
 33:   c->N       = mat->cmap->N/bs;
 34:   c->m       = mat->rmap->N/bs;
 35:   c->rstart  = 0;

 37:   c->ncolors = nis;
 38:   PetscMalloc(nis*sizeof(PetscInt),&c->ncolumns);
 39:   PetscMalloc(nis*sizeof(PetscInt*),&c->columns);
 40:   PetscMalloc(nis*sizeof(PetscInt),&c->nrows);
 41:   PetscMalloc(nis*sizeof(PetscInt*),&c->rows);
 42:   PetscMalloc(nis*sizeof(PetscInt*),&c->columnsforrow);

 44:   MatGetColumnIJ(mat,0,PETSC_FALSE,PETSC_FALSE,&ncols,&ci,&cj,&done);
 45:   if (!done) SETERRQ1(((PetscObject)mat)->comm,PETSC_ERR_SUP,"MatGetColumnIJ() not supported for matrix type %s",((PetscObject)mat)->type_name);

 47:   /*
 48:      Temporary option to allow for debugging/testing
 49:   */
 50:   PetscOptionsGetBool(PETSC_NULL,"-matfdcoloring_slow",&flg,PETSC_NULL);

 52:   PetscMalloc((N+1)*sizeof(PetscInt),&rowhit);
 53:   PetscMalloc((N+1)*sizeof(PetscInt),&columnsforrow);

 55:   for (i=0; i<nis; i++) {
 56:     ISGetLocalSize(isa[i],&n);
 57:     ISGetIndices(isa[i],&is);
 58:     c->ncolumns[i] = n;
 59:     if (n) {
 60:       PetscMalloc(n*sizeof(PetscInt),&c->columns[i]);
 61:       PetscMemcpy(c->columns[i],is,n*sizeof(PetscInt));
 62:     } else {
 63:       c->columns[i]  = 0;
 64:     }

 66:     if (!flg) { /* ------------------------------------------------------------------------------*/
 67:       /* fast, crude version requires O(N*N) work */
 68:       PetscMemzero(rowhit,N*sizeof(PetscInt));
 69:       /* loop over columns*/
 70:       for (j=0; j<n; j++) {
 71:         col  = is[j];
 72:         rows = cj + ci[col];
 73:         m    = ci[col+1] - ci[col];
 74:         /* loop over columns marking them in rowhit */
 75:         for (k=0; k<m; k++) {
 76:           rowhit[*rows++] = col + 1;
 77:         }
 78:       }
 79:       /* count the number of hits */
 80:       nrows = 0;
 81:       for (j=0; j<N; j++) {
 82:         if (rowhit[j]) nrows++;
 83:       }
 84:       c->nrows[i] = nrows;
 85:       PetscMalloc((nrows+1)*sizeof(PetscInt),&c->rows[i]);
 86:       PetscMalloc((nrows+1)*sizeof(PetscInt),&c->columnsforrow[i]);
 87:       nrows       = 0;
 88:       for (j=0; j<N; j++) {
 89:         if (rowhit[j]) {
 90:           c->rows[i][nrows]          = j;
 91:           c->columnsforrow[i][nrows] = rowhit[j] - 1;
 92:           nrows++;
 93:         }
 94:       }
 95:     } else {  /*-------------------------------------------------------------------------------*/
 96:       /* slow version, using rowhit as a linked list */
 97:       PetscInt currentcol,fm,mfm;
 98:       rowhit[N] = N;
 99:       nrows     = 0;
100:       /* loop over columns */
101:       for (j=0; j<n; j++) {
102:         col   = is[j];
103:         rows  = cj + ci[col];
104:         m     = ci[col+1] - ci[col];
105:         /* loop over columns marking them in rowhit */
106:         fm    = N; /* fm points to first entry in linked list */
107:         for (k=0; k<m; k++) {
108:           currentcol = *rows++;
109:           /* is it already in the list? */
110:           do {
111:             mfm  = fm;
112:             fm   = rowhit[fm];
113:           } while (fm < currentcol);
114:           /* not in list so add it */
115:           if (fm != currentcol) {
116:             nrows++;
117:             columnsforrow[currentcol] = col;
118:             /* next three lines insert new entry into linked list */
119:             rowhit[mfm]               = currentcol;
120:             rowhit[currentcol]        = fm;
121:             fm                        = currentcol;
122:             /* fm points to present position in list since we know the columns are sorted */
123:           } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Detected invalid coloring");
124:         }
125:       }
126:       c->nrows[i] = nrows;
127:       PetscMalloc((nrows+1)*sizeof(PetscInt),&c->rows[i]);
128:       PetscMalloc((nrows+1)*sizeof(PetscInt),&c->columnsforrow[i]);
129:       /* now store the linked list of rows into c->rows[i] */
130:       nrows       = 0;
131:       fm          = rowhit[N];
132:       do {
133:         c->rows[i][nrows]            = fm;
134:         c->columnsforrow[i][nrows++] = columnsforrow[fm];
135:         fm                           = rowhit[fm];
136:       } while (fm < N);
137:     } /* ---------------------------------------------------------------------------------------*/
138:     ISRestoreIndices(isa[i],&is);
139:   }
140:   MatRestoreColumnIJ(mat,0,PETSC_FALSE,PETSC_FALSE,&ncols,&ci,&cj,&done);

142:   PetscFree(rowhit);
143:   PetscFree(columnsforrow);

145:   /* Optimize by adding the vscale, and scaleforrow[][] fields */
146:   /*
147:        see the version for MPIAIJ
148:   */
149:   VecCreateGhost(((PetscObject)mat)->comm,mat->rmap->n,PETSC_DETERMINE,0,PETSC_NULL,&c->vscale);
150:   PetscMalloc(c->ncolors*sizeof(PetscInt*),&c->vscaleforrow);
151:   for (k=0; k<c->ncolors; k++) {
152:     PetscMalloc((c->nrows[k]+1)*sizeof(PetscInt),&c->vscaleforrow[k]);
153:     for (l=0; l<c->nrows[k]; l++) {
154:       col = c->columnsforrow[k][l];
155:       c->vscaleforrow[k][l] = col;
156:     }
157:   }
158:   ISColoringRestoreIS(iscoloring,&isa);
159:   return(0);
160: }