xref: /petsc/src/mat/impls/aij/seq/matmatmult.c (revision 09f3b4e5628a00a1eaf17d80982cfbcc515cc9c1)
1 #define PETSCMAT_DLL
2 
3 /*
4   Defines matrix-matrix product routines for pairs of SeqAIJ matrices
5           C = A * B
6 */
7 
8 #include "src/mat/impls/aij/seq/aij.h" /*I "petscmat.h" I*/
9 #include "src/mat/utils/freespace.h"
10 #include "petscbt.h"
11 
12 
13 #undef __FUNCT__
14 #define __FUNCT__ "MatMatMult_SeqAIJ_SeqAIJ"
15 PetscErrorCode MatMatMult_SeqAIJ_SeqAIJ(Mat A,Mat B,MatReuse scall,PetscReal fill,Mat *C)
16 {
17   PetscErrorCode ierr;
18 
19   PetscFunctionBegin;
20   if (scall == MAT_INITIAL_MATRIX){
21     ierr = MatMatMultSymbolic_SeqAIJ_SeqAIJ(A,B,fill,C);CHKERRQ(ierr);
22   }
23   ierr = MatMatMultNumeric_SeqAIJ_SeqAIJ(A,B,*C);CHKERRQ(ierr);
24   PetscFunctionReturn(0);
25 }
26 
27 
28 #undef __FUNCT__
29 #define __FUNCT__ "MatMatMultSymbolic_SeqAIJ_SeqAIJ"
30 PetscErrorCode MatMatMultSymbolic_SeqAIJ_SeqAIJ(Mat A,Mat B,PetscReal fill,Mat *C)
31 {
32   PetscErrorCode     ierr;
33   PetscFreeSpaceList free_space=PETSC_NULL,current_space=PETSC_NULL;
34   Mat_SeqAIJ         *a=(Mat_SeqAIJ*)A->data,*b=(Mat_SeqAIJ*)B->data,*c;
35   PetscInt           *ai=a->i,*aj=a->j,*bi=b->i,*bj=b->j,*bjj,*ci,*cj;
36   PetscInt           am=A->M,bn=B->N,bm=B->M;
37   PetscInt           i,j,anzi,brow,bnzj,cnzi,nlnk,*lnk,nspacedouble=0;
38   MatScalar          *ca;
39   PetscBT            lnkbt;
40 
41   PetscFunctionBegin;
42   /* Set up */
43   /* Allocate ci array, arrays for fill computation and */
44   /* free space for accumulating nonzero column info */
45   ierr = PetscMalloc(((am+1)+1)*sizeof(PetscInt),&ci);CHKERRQ(ierr);
46   ci[0] = 0;
47 
48   /* create and initialize a linked list */
49   nlnk = bn+1;
50   ierr = PetscLLCreate(bn,bn,nlnk,lnk,lnkbt);CHKERRQ(ierr);
51 
52   /* Initial FreeSpace size is fill*(nnz(A)+nnz(B)) */
53   ierr = PetscFreeSpaceGet((PetscInt)(fill*(ai[am]+bi[bm])),&free_space);CHKERRQ(ierr);
54   current_space = free_space;
55 
56   /* Determine symbolic info for each row of the product: */
57   for (i=0;i<am;i++) {
58     anzi = ai[i+1] - ai[i];
59     cnzi = 0;
60     j    = anzi;
61     aj   = a->j + ai[i];
62     while (j){/* assume cols are almost in increasing order, starting from its end saves computation */
63       j--;
64       brow = *(aj + j);
65       bnzj = bi[brow+1] - bi[brow];
66       bjj  = bj + bi[brow];
67       /* add non-zero cols of B into the sorted linked list lnk */
68       ierr = PetscLLAdd(bnzj,bjj,bn,nlnk,lnk,lnkbt);CHKERRQ(ierr);
69       cnzi += nlnk;
70     }
71 
72     /* If free space is not available, make more free space */
73     /* Double the amount of total space in the list */
74     if (current_space->local_remaining<cnzi) {
75       ierr = PetscFreeSpaceGet(current_space->total_array_size,&current_space);CHKERRQ(ierr);
76       nspacedouble++;
77     }
78 
79     /* Copy data into free space, then initialize lnk */
80     ierr = PetscLLClean(bn,bn,cnzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
81     current_space->array           += cnzi;
82     current_space->local_used      += cnzi;
83     current_space->local_remaining -= cnzi;
84 
85     ci[i+1] = ci[i] + cnzi;
86   }
87 
88   /* Column indices are in the list of free space */
89   /* Allocate space for cj, initialize cj, and */
90   /* destroy list of free space and other temporary array(s) */
91   ierr = PetscMalloc((ci[am]+1)*sizeof(PetscInt),&cj);CHKERRQ(ierr);
92   ierr = PetscFreeSpaceContiguous(&free_space,cj);CHKERRQ(ierr);
93   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
94 
95   /* Allocate space for ca */
96   ierr = PetscMalloc((ci[am]+1)*sizeof(MatScalar),&ca);CHKERRQ(ierr);
97   ierr = PetscMemzero(ca,(ci[am]+1)*sizeof(MatScalar));CHKERRQ(ierr);
98 
99   /* put together the new symbolic matrix */
100   ierr = MatCreateSeqAIJWithArrays(A->comm,am,bn,ci,cj,ca,C);CHKERRQ(ierr);
101 
102   /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
103   /* These are PETSc arrays, so change flags so arrays can be deleted by PETSc */
104   c = (Mat_SeqAIJ *)((*C)->data);
105   c->freedata = PETSC_TRUE;
106   c->nonew    = 0;
107 
108   if (nspacedouble){
109     ierr = PetscVerboseInfo(((PetscObject)(*C),"MatMatMultSymbolic_SeqAIJ_SeqAIJ: nspacedouble:%D, nnz(A):%D, nnz(B):%D, fill:%g, nnz(C):%D\n",nspacedouble,ai[am],bi[bm],fill,ci[am]));CHKERRQ(ierr);
110   }
111   PetscFunctionReturn(0);
112 }
113 
114 
115 #undef __FUNCT__
116 #define __FUNCT__ "MatMatMultNumeric_SeqAIJ_SeqAIJ"
117 PetscErrorCode MatMatMultNumeric_SeqAIJ_SeqAIJ(Mat A,Mat B,Mat C)
118 {
119   PetscErrorCode ierr;
120   PetscInt       flops=0;
121   Mat_SeqAIJ     *a = (Mat_SeqAIJ *)A->data;
122   Mat_SeqAIJ     *b = (Mat_SeqAIJ *)B->data;
123   Mat_SeqAIJ     *c = (Mat_SeqAIJ *)C->data;
124   PetscInt       *ai=a->i,*aj=a->j,*bi=b->i,*bj=b->j,*bjj,*ci=c->i,*cj=c->j;
125   PetscInt       am=A->M,cm=C->M;
126   PetscInt       i,j,k,anzi,bnzi,cnzi,brow,nextb;
127   MatScalar      *aa=a->a,*ba=b->a,*baj,*ca=c->a;
128 
129   PetscFunctionBegin;
130   /* clean old values in C */
131   ierr = PetscMemzero(ca,ci[cm]*sizeof(MatScalar));CHKERRQ(ierr);
132   /* Traverse A row-wise. */
133   /* Build the ith row in C by summing over nonzero columns in A, */
134   /* the rows of B corresponding to nonzeros of A. */
135   for (i=0;i<am;i++) {
136     anzi = ai[i+1] - ai[i];
137     for (j=0;j<anzi;j++) {
138       brow = *aj++;
139       bnzi = bi[brow+1] - bi[brow];
140       bjj  = bj + bi[brow];
141       baj  = ba + bi[brow];
142       nextb = 0;
143       for (k=0; nextb<bnzi; k++) {
144         if (cj[k] == bjj[nextb]){ /* ccol == bcol */
145           ca[k] += (*aa)*baj[nextb++];
146         }
147       }
148       flops += 2*bnzi;
149       aa++;
150     }
151     cnzi = ci[i+1] - ci[i];
152     ca += cnzi;
153     cj += cnzi;
154   }
155   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
156   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
157 
158   ierr = PetscLogFlops(flops);CHKERRQ(ierr);
159   PetscFunctionReturn(0);
160 }
161 
162 
163 #undef __FUNCT__
164 #define __FUNCT__ "MatMatMultTranspose_SeqAIJ_SeqAIJ"
165 PetscErrorCode MatMatMultTranspose_SeqAIJ_SeqAIJ(Mat A,Mat B,MatReuse scall,PetscReal fill,Mat *C) {
166   PetscErrorCode ierr;
167 
168   PetscFunctionBegin;
169   if (scall == MAT_INITIAL_MATRIX){
170     ierr = MatMatMultTransposeSymbolic_SeqAIJ_SeqAIJ(A,B,fill,C);CHKERRQ(ierr);
171   }
172   ierr = MatMatMultTransposeNumeric_SeqAIJ_SeqAIJ(A,B,*C);CHKERRQ(ierr);
173   PetscFunctionReturn(0);
174 }
175 
176 #undef __FUNCT__
177 #define __FUNCT__ "MatMatMultTransposeSymbolic_SeqAIJ_SeqAIJ"
178 PetscErrorCode MatMatMultTransposeSymbolic_SeqAIJ_SeqAIJ(Mat A,Mat B,PetscReal fill,Mat *C)
179 {
180   PetscErrorCode ierr;
181   Mat            At;
182   PetscInt       *ati,*atj;
183 
184   PetscFunctionBegin;
185   /* create symbolic At */
186   ierr = MatGetSymbolicTranspose_SeqAIJ(A,&ati,&atj);CHKERRQ(ierr);
187   ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,A->n,A->m,ati,atj,PETSC_NULL,&At);CHKERRQ(ierr);
188 
189   /* get symbolic C=At*B */
190   ierr = MatMatMultSymbolic_SeqAIJ_SeqAIJ(At,B,fill,C);CHKERRQ(ierr);
191 
192   /* clean up */
193   ierr = MatDestroy(At);CHKERRQ(ierr);
194   ierr = MatRestoreSymbolicTranspose_SeqAIJ(A,&ati,&atj);CHKERRQ(ierr);
195 
196   PetscFunctionReturn(0);
197 }
198 
199 #undef __FUNCT__
200 #define __FUNCT__ "MatMatMultTransposeNumeric_SeqAIJ_SeqAIJ"
201 PetscErrorCode MatMatMultTransposeNumeric_SeqAIJ_SeqAIJ(Mat A,Mat B,Mat C)
202 {
203   PetscErrorCode ierr;
204   Mat_SeqAIJ     *a=(Mat_SeqAIJ*)A->data,*b=(Mat_SeqAIJ*)B->data,*c=(Mat_SeqAIJ*)C->data;
205   PetscInt       am=A->m,anzi,*ai=a->i,*aj=a->j,*bi=b->i,*bj,bnzi,nextb;
206   PetscInt       cm=C->m,*ci=c->i,*cj=c->j,crow,*cjj,i,j,k,flops=0;
207   MatScalar      *aa=a->a,*ba,*ca=c->a,*caj;
208 
209   PetscFunctionBegin;
210   /* clear old values in C */
211   ierr = PetscMemzero(ca,ci[cm]*sizeof(MatScalar));CHKERRQ(ierr);
212 
213   /* compute A^T*B using outer product (A^T)[:,i]*B[i,:] */
214   for (i=0;i<am;i++) {
215     bj   = b->j + bi[i];
216     ba   = b->a + bi[i];
217     bnzi = bi[i+1] - bi[i];
218     anzi = ai[i+1] - ai[i];
219     for (j=0; j<anzi; j++) {
220       nextb = 0;
221       crow  = *aj++;
222       cjj   = cj + ci[crow];
223       caj   = ca + ci[crow];
224       /* perform sparse axpy operation.  Note cjj includes bj. */
225       for (k=0; nextb<bnzi; k++) {
226         if (cjj[k] == *(bj+nextb)) { /* ccol == bcol */
227           caj[k] += (*aa)*(*(ba+nextb));
228           nextb++;
229         }
230       }
231       flops += 2*bnzi;
232       aa++;
233     }
234   }
235 
236   /* Assemble the final matrix and clean up */
237   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
238   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
239   ierr = PetscLogFlops(flops);CHKERRQ(ierr);
240   PetscFunctionReturn(0);
241 }
242