xref: /petsc/src/mat/impls/aij/seq/fdaij.c (revision f86b9fba6afbb510b5a4e5909e38406c0861ad7a)
1 
2 #include <../src/mat/impls/aij/seq/aij.h>
3 #include <../src/mat/impls/baij/seq/baij.h>
4 
5 /*
6     This routine is shared by SeqAIJ and SeqBAIJ matrices,
7     since it operators only on the nonzero structure of the elements or blocks.
8 */
9 #undef __FUNCT__
10 #define __FUNCT__ "MatFDColoringSetUp_SeqXAIJ"
11 PetscErrorCode MatFDColoringSetUp_SeqXAIJ(Mat mat,ISColoring iscoloring,MatFDColoring c)
12 {
13   PetscErrorCode ierr;
14   PetscInt       i,n,nrows,N,j,k,m,ncols,col,nis=iscoloring->n,*rowhit,bs,bs2,*spidx,nz;
15   const PetscInt *is,*row,*ci,*cj;
16   IS             *isa;
17   PetscBool      isBAIJ;
18   PetscScalar    *A_val,**valaddrhit;
19   MatEntry       *Jentry,*Jentry_new;
20   PetscInt       *color_start,nz_new,row_end,*row_start,*nrows_new;
21   PetscInt       brows,bcols;
22 
23   PetscFunctionBegin;
24   ierr = ISColoringGetIS(iscoloring,PETSC_IGNORE,&isa);CHKERRQ(ierr);
25 
26   ierr = MatGetBlockSize(mat,&bs);CHKERRQ(ierr);
27   ierr = PetscObjectTypeCompare((PetscObject)mat,MATSEQBAIJ,&isBAIJ);CHKERRQ(ierr);
28   if (isBAIJ) {
29     Mat_SeqBAIJ *spA = (Mat_SeqBAIJ*)mat->data;
30     A_val = spA->a;
31     nz    = spA->nz;
32   } else {
33     Mat_SeqAIJ  *spA = (Mat_SeqAIJ*)mat->data;
34     A_val = spA->a;
35     nz    = spA->nz;
36     bs    = 1; /* only bs=1 is supported for SeqAIJ matrix */
37   }
38 
39   N         = mat->cmap->N/bs;
40   c->M      = mat->rmap->N/bs;   /* set total rows, columns and local rows */
41   c->N      = mat->cmap->N/bs;
42   c->m      = mat->rmap->N/bs;
43   c->rstart = 0;
44 
45   c->ncolors = nis;
46   ierr       = PetscMalloc(nis*sizeof(PetscInt),&c->ncolumns);CHKERRQ(ierr);
47   ierr       = PetscMalloc(nis*sizeof(PetscInt*),&c->columns);CHKERRQ(ierr);
48   ierr       = PetscMalloc(nis*sizeof(PetscInt),&c->nrows);CHKERRQ(ierr);
49   ierr       = PetscLogObjectMemory((PetscObject)c,3*nis*sizeof(PetscInt));CHKERRQ(ierr);
50 
51   ierr       = PetscMalloc(nz*sizeof(MatEntry),&Jentry);CHKERRQ(ierr);
52   ierr       = PetscLogObjectMemory((PetscObject)c,nz*sizeof(MatEntry));CHKERRQ(ierr);
53   c->matentry = Jentry;
54 
55   ierr       = PetscMalloc2(nis+1,PetscInt,&color_start,nis+1,PetscInt,&row_start);CHKERRQ(ierr);
56 
57   if (isBAIJ) {
58     ierr = MatGetColumnIJ_SeqBAIJ_Color(mat,0,PETSC_FALSE,PETSC_FALSE,&ncols,&ci,&cj,&spidx,NULL);CHKERRQ(ierr);
59   } else {
60     ierr = MatGetColumnIJ_SeqAIJ_Color(mat,0,PETSC_FALSE,PETSC_FALSE,&ncols,&ci,&cj,&spidx,NULL);CHKERRQ(ierr);
61   }
62 
63   ierr = PetscMalloc2(c->m,PetscInt,&rowhit,c->m,PetscScalar*,&valaddrhit);CHKERRQ(ierr);
64   ierr = PetscMemzero(rowhit,c->m*sizeof(PetscInt));CHKERRQ(ierr);
65 
66   // estimate bcol
67   PetscReal mem;
68   mem = nz*(sizeof(PetscScalar) + sizeof(PetscInt)) + 3*c->m*sizeof(PetscInt);
69   bcols = (PetscInt)(0.5*mem /(c->m*sizeof(PetscScalar)));
70   if (bcols > nis) bcols = nis;
71   brows = 1000/bcols;
72 
73   nz = 0;
74   for (i=0; i<nis; i++) { /* loop over colors */
75     color_start[i] = nz;
76 
77     ierr = ISGetLocalSize(isa[i],&n);CHKERRQ(ierr);
78     ierr = ISGetIndices(isa[i],&is);CHKERRQ(ierr);
79 
80     c->ncolumns[i] = n;
81     if (n) {
82       ierr = PetscMalloc(n*sizeof(PetscInt),&c->columns[i]);CHKERRQ(ierr);
83       ierr = PetscLogObjectMemory((PetscObject)c,n*sizeof(PetscInt));CHKERRQ(ierr);
84       ierr = PetscMemcpy(c->columns[i],is,n*sizeof(PetscInt));CHKERRQ(ierr);
85     } else {
86       c->columns[i] = 0;
87     }
88 
89     /* fast, crude version requires O(N*N) work */
90     bs2   = bs*bs;
91     nrows = 0;
92     for (j=0; j<n; j++) {  /* loop over columns */
93       col    = is[j];
94       row    = cj + ci[col];
95       m      = ci[col+1] - ci[col];
96       nrows += m;
97       for (k=0; k<m; k++) {  /* loop over columns marking them in rowhit */
98         rowhit[*row]       = col + 1;
99         valaddrhit[*row++] = &A_val[bs2*spidx[ci[col] + k]];
100       }
101     }
102     c->nrows[i] = nrows; /* total num of rows for this color */
103 
104     for (j=0; j<N; j++) { /* loop over rows */
105       if (rowhit[j]) {
106         Jentry[nz].row     = j;              /* local row index */
107         Jentry[nz].col     = rowhit[j] - 1;  /* local column index */
108         Jentry[nz].valaddr = valaddrhit[j];  /* address of mat value for this entry */
109         nz++;
110         rowhit[j] = 0.0;                     /* zero rowhit for reuse */
111       }
112     }
113     ierr = ISRestoreIndices(isa[i],&is);CHKERRQ(ierr);
114   }
115   color_start[nis] = nz;
116 
117   // ---------- reorder Jentry ------------
118   if (!isBAIJ && bcols > 1) {
119     PetscInt nbcols = 0;
120 
121     ierr = PetscMalloc(nz*sizeof(MatEntry),&Jentry_new);CHKERRQ(ierr);
122     for (i=0; i<nis; i++) row_start[i] = 0;
123 
124 
125     ierr = PetscOptionsInt("-bcols","The number of block columns","",bcols,&bcols,NULL);CHKERRQ(ierr);
126     if (bcols > nis) bcols = nis;
127     c->brows = brows;
128     c->bcols = bcols;
129 
130     ierr = PetscMalloc(nis*sizeof(PetscInt),&nrows_new);CHKERRQ(ierr);
131 
132     nz_new  = 0;
133     for (i=0; i<nis; i+=bcols) { /* loop over colors */
134       if (i + bcols > nis) bcols = nis - i;
135 
136       row_end = brows;
137       m       = mat->rmap->n;
138       if (row_end > m) row_end = m;
139       while (row_end <= m) { /* loop over block rows */
140         for (j=0; j<bcols; j++) {       /* loop over block columns */
141           nrows = c->nrows[i+j];
142           for (nz=color_start[i+j]; nz<color_start[i+j+1]; nz++) { /* for each Jentry */
143             if (row_start[i+j] >= nrows) break;
144             if (Jentry[nz].row >= row_end) {
145               color_start[i+j] = nz;
146               break;
147             } else {
148               Jentry_new[nz_new].row     = Jentry[nz].row + j*m; /* index in dy-array */
149               Jentry_new[nz_new].col     = Jentry[nz].col;
150               Jentry_new[nz_new].valaddr = Jentry[nz].valaddr;
151               nz_new++;
152               row_start[i+j]++;
153             }
154           }
155         }
156         if (row_end == m) break;
157         row_end += brows;
158         if (row_end > m) row_end = m;
159       }
160       nrows_new[nbcols++] = nz_new;
161     }
162     for (i=nbcols-1; i>0; i--) nrows_new[i] -= nrows_new[i-1];
163     ierr = PetscFree(c->nrows);CHKERRQ(ierr);
164     c->nrows = nrows_new;
165 
166     ierr = PetscFree(Jentry);CHKERRQ(ierr);
167     c->matentry = Jentry_new;
168     ierr = PetscMalloc(c->bcols*mat->rmap->n*sizeof(PetscScalar),&c->dy);CHKERRQ(ierr);
169   }
170   //---------------------------------------
171 
172   if (isBAIJ) {
173     ierr = MatRestoreColumnIJ_SeqBAIJ_Color(mat,0,PETSC_FALSE,PETSC_FALSE,&ncols,&ci,&cj,&spidx,NULL);CHKERRQ(ierr);
174     ierr = PetscMalloc(bs*mat->rmap->n*sizeof(PetscScalar),&c->dy);CHKERRQ(ierr);
175   } else {
176     ierr = MatRestoreColumnIJ_SeqAIJ_Color(mat,0,PETSC_FALSE,PETSC_FALSE,&ncols,&ci,&cj,&spidx,NULL);CHKERRQ(ierr);
177   }
178   ierr = PetscFree2(rowhit,valaddrhit);CHKERRQ(ierr);
179   ierr = ISColoringRestoreIS(iscoloring,&isa);CHKERRQ(ierr);
180   ierr = PetscFree2(color_start,row_start);CHKERRQ(ierr);
181 
182   c->ctype = IS_COLORING_GHOSTED;
183   ierr = VecCreateGhost(PetscObjectComm((PetscObject)mat),mat->rmap->n,PETSC_DETERMINE,0,NULL,&c->vscale);CHKERRQ(ierr);
184   PetscFunctionReturn(0);
185 }
186