xref: /petsc/src/mat/impls/aij/seq/matptap.c (revision 8cdbd7576f676fd2f0cf4ce91c9fbf7f9b0d4574)
1 
2 /*
3   Defines projective product routines where A is a SeqAIJ matrix
4           C = P^T * A * P
5 */
6 
7 #include <../src/mat/impls/aij/seq/aij.h>   /*I "petscmat.h" I*/
8 #include <../src/mat/utils/freespace.h>
9 #include <petscbt.h>
10 
11 #undef __FUNCT__
12 #define __FUNCT__ "MatPtAPSymbolic_SeqAIJ"
13 PetscErrorCode MatPtAPSymbolic_SeqAIJ(Mat A,Mat P,PetscReal fill,Mat *C)
14 {
15   PetscErrorCode ierr;
16 
17   PetscFunctionBegin;
18   if (!P->ops->ptapsymbolic_seqaij) SETERRQ2(((PetscObject)A)->comm,PETSC_ERR_SUP,"Not implemented for A=%s and P=%s",((PetscObject)A)->type_name,((PetscObject)P)->type_name);
19   ierr = (*P->ops->ptapsymbolic_seqaij)(A,P,fill,C);CHKERRQ(ierr);
20   PetscFunctionReturn(0);
21 }
22 
23 #undef __FUNCT__
24 #define __FUNCT__ "MatPtAPNumeric_SeqAIJ"
25 PetscErrorCode MatPtAPNumeric_SeqAIJ(Mat A,Mat P,Mat C)
26 {
27   PetscErrorCode ierr;
28 
29   PetscFunctionBegin;
30   if (!P->ops->ptapnumeric_seqaij) SETERRQ2(((PetscObject)A)->comm,PETSC_ERR_SUP,"Not implemented for A=%s and P=%s",((PetscObject)A)->type_name,((PetscObject)P)->type_name);
31   ierr = (*P->ops->ptapnumeric_seqaij)(A,P,C);CHKERRQ(ierr);
32   PetscFunctionReturn(0);
33 }
34 
35 #undef __FUNCT__
36 #define __FUNCT__ "PetscContainerDestroy_Mat_PtAP"
37 PetscErrorCode PetscContainerDestroy_Mat_PtAP(void *ptr)
38 {
39   PetscErrorCode ierr;
40   Mat_PtAP       *ptap=(Mat_PtAP*)ptr;
41 
42   PetscFunctionBegin;
43   ierr = PetscFree(ptap->apa);CHKERRQ(ierr);
44   ierr = PetscFree(ptap->api);CHKERRQ(ierr);
45   ierr = PetscFree(ptap->apj);CHKERRQ(ierr);
46   ierr = PetscFree(ptap);CHKERRQ(ierr);
47   PetscFunctionReturn(0);
48 }
49 
50 #undef __FUNCT__
51 #define __FUNCT__ "MatDestroy_SeqAIJ_PtAP"
52 PetscErrorCode MatDestroy_SeqAIJ_PtAP(Mat A)
53 {
54   PetscErrorCode ierr;
55   PetscContainer container;
56   Mat_PtAP       *ptap=PETSC_NULL;
57 
58   PetscFunctionBegin;
59   ierr = PetscObjectQuery((PetscObject)A,"Mat_PtAP",(PetscObject *)&container);CHKERRQ(ierr);
60   if (!container) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Container does not exit");
61   ierr = PetscContainerGetPointer(container,(void **)&ptap);CHKERRQ(ierr);
62   A->ops->destroy = ptap->destroy;
63   if (A->ops->destroy) {
64     ierr = (*A->ops->destroy)(A);CHKERRQ(ierr);
65   }
66   ierr = PetscObjectCompose((PetscObject)A,"Mat_PtAP",0);CHKERRQ(ierr);
67   PetscFunctionReturn(0);
68 }
69 
70 #undef __FUNCT__
71 #define __FUNCT__ "MatPtAPSymbolic_SeqAIJ_SeqAIJ"
72 PetscErrorCode MatPtAPSymbolic_SeqAIJ_SeqAIJ(Mat A,Mat P,PetscReal fill,Mat *C)
73 {
74   PetscErrorCode     ierr;
75   Mat_SeqAIJ         *a = (Mat_SeqAIJ*)A->data,*p = (Mat_SeqAIJ*)P->data,*c;
76   PetscInt           *pti,*ptj,*ptJ,*ai=a->i,*aj=a->j,*pi=p->i,*pj=p->j,*api,*apj;
77   PetscInt           *ci,*cj,ndouble_ap,ndouble_ptap;
78   PetscInt           an=A->cmap->N,am=A->rmap->N,pn=P->cmap->N;
79   MatScalar          *ca;
80   Mat_PtAP           *ptap;
81   PetscContainer     container;
82 
83   PetscFunctionBegin;
84   /* Get ij structure of Pt = P^T */
85   ierr = MatGetSymbolicTranspose_SeqAIJ(P,&pti,&ptj);CHKERRQ(ierr);
86   ptJ=ptj;
87 
88   /* Get structure of AP = A*P */
89   ierr = MatGetSymbolicMatMatMult_SeqAIJ_SeqAIJ(am,ai,aj,an,pn,pi,pj,fill,&api,&apj,&ndouble_ap);CHKERRQ(ierr);
90 
91   /* Get structure of C = Pt*AP */
92   ierr = MatGetSymbolicMatMatMult_SeqAIJ_SeqAIJ(pn,pti,ptj,am,pn,api,apj,fill,&ci,&cj,&ndouble_ptap);CHKERRQ(ierr);
93 #if defined(MV)
94   /* Allocate ci array, arrays for fill computation and */
95   /* free space for accumulating nonzero column info */
96   ierr = PetscMalloc((pn+1)*sizeof(PetscInt),&ci);CHKERRQ(ierr);
97   ci[0] = 0;
98 
99   ierr = PetscMalloc((2*an+1)*sizeof(PetscInt),&ptadenserow);CHKERRQ(ierr);
100   ierr = PetscMemzero(ptadenserow,(2*an+1)*sizeof(PetscInt));CHKERRQ(ierr);
101   ptasparserow = ptadenserow  + an;
102 
103   /* create and initialize a linked list */
104   nlnk = pn+1;
105   ierr = PetscLLCreate(pn,pn,nlnk,lnk,lnkbt);CHKERRQ(ierr);
106 
107   /* Set initial free space to be fill*nnz(A). */
108   /* This should be reasonable if sparsity of PtAP is similar to that of A. */
109   ierr          = PetscFreeSpaceGet((PetscInt)(fill*ai[am]),&free_space);
110   current_space = free_space;
111 
112   /* Determine symbolic info for each row of C: */
113   for (i=0;i<pn;i++) {
114     ptnzi  = pti[i+1] - pti[i];
115     ptanzi = 0;
116     /* Determine symbolic row of PtA: */
117     for (j=0;j<ptnzi;j++) {
118       arow = *ptJ++;
119       anzj = ai[arow+1] - ai[arow];
120       ajj  = aj + ai[arow];
121       for (k=0;k<anzj;k++) {
122         if (!ptadenserow[ajj[k]]) {
123           ptadenserow[ajj[k]]    = -1;
124           ptasparserow[ptanzi++] = ajj[k];
125         }
126       }
127     }
128     /* Using symbolic info for row of PtA, determine symbolic info for row of C: */
129     ptaj = ptasparserow;
130     cnzi   = 0;
131     for (j=0;j<ptanzi;j++) {
132       prow = *ptaj++;
133       pnzj = pi[prow+1] - pi[prow];
134       pjj  = pj + pi[prow];
135       /* add non-zero cols of P into the sorted linked list lnk */
136       ierr = PetscLLAdd(pnzj,pjj,pn,nlnk,lnk,lnkbt);CHKERRQ(ierr);
137       cnzi += nlnk;
138     }
139 
140     /* If free space is not available, make more free space */
141     /* Double the amount of total space in the list */
142     if (current_space->local_remaining<cnzi) {
143       ierr = PetscFreeSpaceGet(cnzi+current_space->total_array_size,&current_space);CHKERRQ(ierr);
144       nspacedouble++;
145     }
146 
147     /* Copy data into free space, and zero out denserows */
148     ierr = PetscLLClean(pn,pn,cnzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
149     current_space->array           += cnzi;
150     current_space->local_used      += cnzi;
151     current_space->local_remaining -= cnzi;
152 
153     for (j=0;j<ptanzi;j++) {
154       ptadenserow[ptasparserow[j]] = 0;
155     }
156     /* Aside: Perhaps we should save the pta info for the numerical factorization. */
157     /*        For now, we will recompute what is needed. */
158     ci[i+1] = ci[i] + cnzi;
159   }
160   /* nnz is now stored in ci[ptm], column indices are in the list of free space */
161   /* Allocate space for cj, initialize cj, and */
162   /* destroy list of free space and other temporary array(s) */
163   ierr = PetscMalloc((ci[pn]+1)*sizeof(PetscInt),&cj);CHKERRQ(ierr);
164   ierr = PetscFreeSpaceContiguous(&free_space,cj);CHKERRQ(ierr);
165   ierr = PetscFree(ptadenserow);CHKERRQ(ierr);
166   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
167 
168 #endif
169 
170   /* Allocate space for ca */
171   ierr = PetscMalloc((ci[pn]+1)*sizeof(MatScalar),&ca);CHKERRQ(ierr);
172   ierr = PetscMemzero(ca,(ci[pn]+1)*sizeof(MatScalar));CHKERRQ(ierr);
173 
174   /* put together the new matrix */
175   ierr = MatCreateSeqAIJWithArrays(((PetscObject)A)->comm,pn,pn,ci,cj,ca,C);CHKERRQ(ierr);
176 
177   /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
178   /* Since these are PETSc arrays, change flags to free them as necessary. */
179   c          = (Mat_SeqAIJ *)(*C)->data;
180   c->free_a  = PETSC_TRUE;
181   c->free_ij = PETSC_TRUE;
182   c->nonew   = 0;
183 
184   /* create a supporting struct for reuse by MatPtAPNumeric(), attach it to *C */
185   ierr = PetscNew(Mat_PtAP,&ptap);CHKERRQ(ierr);
186 
187   /* attach the supporting struct to C */
188   ierr = PetscContainerCreate(PETSC_COMM_SELF,&container);CHKERRQ(ierr);
189   ierr = PetscContainerSetPointer(container,ptap);CHKERRQ(ierr);
190   ierr = PetscContainerSetUserDestroy(container,PetscContainerDestroy_Mat_PtAP);CHKERRQ(ierr);
191   ierr = PetscObjectCompose((PetscObject)(*C),"Mat_PtAP",(PetscObject)container);CHKERRQ(ierr);
192   ierr = PetscContainerDestroy(&container);CHKERRQ(ierr);
193 
194   ptap->destroy      = (*C)->ops->destroy;
195   (*C)->ops->destroy = MatDestroy_SeqAIJ_PtAP;
196 
197   /* Allocate temporary array for storage of one row of A*P */
198   ierr = PetscMalloc((pn+1)*sizeof(PetscScalar),&ptap->apa);CHKERRQ(ierr);
199   ierr = PetscMemzero(ptap->apa,(pn+1)*sizeof(MatScalar));CHKERRQ(ierr);
200   ptap->api = api;
201   ptap->apj = apj;
202 
203   /* Clean up. */
204   ierr = MatRestoreSymbolicTranspose_SeqAIJ(P,&pti,&ptj);CHKERRQ(ierr);
205 #if defined(PETSC_USE_INFO)
206   if (ci[pn] != 0) {
207     PetscReal apfill,ptapfill;
208     apfill = ((PetscReal)api[am])/(ai[am]+pi[an]);
209     if (apfill < 1.0) apfill = 1.0;
210     ierr = PetscInfo3((*C),"A*P: Reallocs %D; Fill ratio: given %G needed %G.\n",ndouble_ap,fill,apfill);CHKERRQ(ierr);
211     ptapfill = ((PetscReal)ci[pn])/(pi[an]+api[am]);
212     if (ptapfill < 1.0) ptapfill = 1.0;
213     ierr = PetscInfo3((*C),"Pt*AP: Reallocs %D; Fill ratio: given %G needed %G.\n",ndouble_ptap,fill,ptapfill);CHKERRQ(ierr);
214 
215     ierr = PetscInfo1((*C),"Use MatPtAP(A,P,MatReuse,%G,&C) for best performance.\n",PetscMax(apfill,ptapfill));CHKERRQ(ierr);
216     ierr = PetscInfo4((*C),"nonzeros: A %D, P %D, A*P %D, C=PtAP %D\n",ai[am],pi[an],api[am],ci[pn]);CHKERRQ(ierr);
217   } else {
218     ierr = PetscInfo((*C),"Empty matrix product\n");CHKERRQ(ierr);
219   }
220 #endif
221   PetscFunctionReturn(0);
222 }
223 
224 #undef __FUNCT__
225 #define __FUNCT__ "MatPtAPNumeric_SeqAIJ_SeqAIJ"
226 PetscErrorCode MatPtAPNumeric_SeqAIJ_SeqAIJ(Mat A,Mat P,Mat C)
227 {
228   PetscErrorCode  ierr;
229   Mat_SeqAIJ      *a  = (Mat_SeqAIJ *) A->data;
230   Mat_SeqAIJ      *p  = (Mat_SeqAIJ *) P->data;
231   Mat_SeqAIJ      *c  = (Mat_SeqAIJ *) C->data;
232   PetscInt        *ai=a->i,*aj=a->j,*pi=p->i,*pj=p->j,*ci=c->i,*cj=c->j;
233   PetscScalar     *aa=a->a,*pa=p->a;
234   PetscInt        *apj,*pcol,*cjj,cnz;
235   PetscInt        am=A->rmap->N,cm=C->rmap->N;
236   PetscInt        i,j,k,anz,apnz,pnz,prow,crow,apcol,nextap;
237   PetscScalar     *apa,*pval,*ca=c->a,*caj;
238   PetscBool       sparse_axpy=PETSC_FALSE;
239   Mat_PtAP        *ptap;
240   PetscContainer  container;
241 
242   PetscFunctionBegin;
243   ierr = PetscOptionsGetBool(PETSC_NULL,"-matptap_spaxpy",&sparse_axpy,PETSC_NULL);CHKERRQ(ierr);
244   ierr = PetscObjectQuery((PetscObject)C,"Mat_PtAP",(PetscObject *)&container);CHKERRQ(ierr);
245   if (!container) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Container does not exit");
246   ierr  = PetscContainerGetPointer(container,(void **)&ptap);CHKERRQ(ierr);
247 
248   /* Get temporary array for storage of one row of A*P */
249   apa = ptap->apa;
250 
251   /* Clear old values in C */
252   ierr = PetscMemzero(ca,ci[cm]*sizeof(MatScalar));CHKERRQ(ierr);
253 
254   for (i=0;i<am;i++) {
255     /* Form sparse row of AP[i,:] = A[i,:]*P */
256     anz  = ai[i+1] - ai[i];
257     apnz = 0;
258     for (j=0; j<anz; j++) {
259       prow = aj[j];
260       pnz  = pi[prow+1] - pi[prow];
261       pcol = pj + pi[prow];
262       pval = pa + pi[prow];
263       for (k=0; k<pnz; k++) {
264         apa[pcol[k]] += aa[j]*pval[k];
265       }
266       ierr = PetscLogFlops(2.0*pnz);CHKERRQ(ierr);
267     }
268     aj += anz; aa += anz;
269 
270     /* Compute P^T*A*P using outer product P[i,:]^T*AP[i,:]. */
271     apj  = ptap->apj + ptap->api[i];
272     apnz = ptap->api[i+1] - ptap->api[i];
273     pnz  = pi[i+1] - pi[i];
274     pcol = pj + pi[i];
275     pval = pa + pi[i];
276 
277     if (sparse_axpy){  /* Perform sparse axpy */
278       for (j=0; j<pnz; j++) {
279         crow   = pcol[j];
280         cjj    = cj + ci[crow];
281         caj    = ca + ci[crow];
282         nextap = 0;
283         apcol  = apj[nextap];
284         for (k=0; nextap<apnz; k++) {
285           if (cjj[k] == apcol) {
286             caj[k] += pval[j]*apa[apcol];
287             apcol   = apj[++nextap];
288           }
289         }
290         ierr = PetscLogFlops(2.0*apnz);CHKERRQ(ierr);
291       }
292     } else { /* Perform dense axpy */
293       for (j=0; j<pnz; j++) {
294         crow = pcol[j];
295         cjj  = cj + ci[crow];
296         caj  = ca + ci[crow];
297         cnz  = ci[crow+1] - ci[crow];
298         for (k=0; k<cnz; k++){
299           caj[k] += pval[j]*apa[cjj[k]];
300         }
301         ierr = PetscLogFlops(2.0*cnz);CHKERRQ(ierr);
302       }
303     }
304 
305     /* Zero the current row info for A*P */
306     for (j=0; j<apnz; j++) {
307       apcol      = apj[j];
308       apa[apcol] = 0.;
309     }
310   }
311 
312   /* Assemble the final matrix and clean up */
313   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
314   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
315   PetscFunctionReturn(0);
316 }
317