xref: /petsc/src/mat/utils/axpy.c (revision feff33ee0b5b037fa8f9f294dede656a2f85cc47)
1 
2 #include <petsc/private/matimpl.h>  /*I   "petscmat.h"  I*/
3 
4 /*@
5    MatAXPY - Computes Y = a*X + Y.
6 
7    Logically  Collective on Mat
8 
9    Input Parameters:
10 +  a - the scalar multiplier
11 .  X - the first matrix
12 .  Y - the second matrix
13 -  str - either SAME_NONZERO_PATTERN, DIFFERENT_NONZERO_PATTERN
14          or SUBSET_NONZERO_PATTERN (nonzeros of X is a subset of Y's)
15 
16    Level: intermediate
17 
18 .keywords: matrix, add
19 
20 .seealso: MatAYPX()
21  @*/
22 PetscErrorCode MatAXPY(Mat Y,PetscScalar a,Mat X,MatStructure str)
23 {
24   PetscErrorCode ierr;
25   PetscInt       m1,m2,n1,n2;
26   PetscBool      sametype;
27 
28   PetscFunctionBegin;
29   PetscValidHeaderSpecific(X,MAT_CLASSID,3);
30   PetscValidHeaderSpecific(Y,MAT_CLASSID,1);
31   PetscValidLogicalCollectiveScalar(Y,a,2);
32   ierr = MatGetSize(X,&m1,&n1);CHKERRQ(ierr);
33   ierr = MatGetSize(Y,&m2,&n2);CHKERRQ(ierr);
34   if (m1 != m2 || n1 != n2) SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Non conforming matrix add: %D %D %D %D",m1,m2,n1,n2);
35 
36   ierr = PetscStrcmp(((PetscObject)X)->type_name,((PetscObject)Y)->type_name,&sametype);CHKERRQ(ierr);
37   ierr = PetscLogEventBegin(MAT_AXPY,Y,0,0,0);CHKERRQ(ierr);
38   if (Y->ops->axpy && sametype) {
39     ierr = (*Y->ops->axpy)(Y,a,X,str);CHKERRQ(ierr);
40   } else {
41     ierr = MatAXPY_Basic(Y,a,X,str);CHKERRQ(ierr);
42   }
43   ierr = PetscLogEventEnd(MAT_AXPY,Y,0,0,0);CHKERRQ(ierr);
44 #if defined(PETSC_HAVE_VIENNACL) || defined(PETSC_HAVE_VECCUDA)
45   if (Y->valid_GPU_matrix != PETSC_OFFLOAD_UNALLOCATED) {
46     Y->valid_GPU_matrix = PETSC_OFFLOAD_CPU;
47   }
48 #endif
49   PetscFunctionReturn(0);
50 }
51 
52 PetscErrorCode MatAXPY_Basic(Mat Y,PetscScalar a,Mat X,MatStructure str)
53 {
54   PetscInt          i,start,end,j,ncols,m,n;
55   PetscErrorCode    ierr;
56   const PetscInt    *row;
57   PetscScalar       *val;
58   const PetscScalar *vals;
59 
60   PetscFunctionBegin;
61   ierr = MatGetSize(X,&m,&n);CHKERRQ(ierr);
62   ierr = MatGetOwnershipRange(X,&start,&end);CHKERRQ(ierr);
63   if (a == 1.0) {
64     for (i = start; i < end; i++) {
65       ierr = MatGetRow(X,i,&ncols,&row,&vals);CHKERRQ(ierr);
66       ierr = MatSetValues(Y,1,&i,ncols,row,vals,ADD_VALUES);CHKERRQ(ierr);
67       ierr = MatRestoreRow(X,i,&ncols,&row,&vals);CHKERRQ(ierr);
68     }
69   } else {
70     ierr = PetscMalloc1(n+1,&val);CHKERRQ(ierr);
71     for (i=start; i<end; i++) {
72       ierr = MatGetRow(X,i,&ncols,&row,&vals);CHKERRQ(ierr);
73       for (j=0; j<ncols; j++) {
74         val[j] = a*vals[j];
75       }
76       ierr = MatSetValues(Y,1,&i,ncols,row,val,ADD_VALUES);CHKERRQ(ierr);
77       ierr = MatRestoreRow(X,i,&ncols,&row,&vals);CHKERRQ(ierr);
78     }
79     ierr = PetscFree(val);CHKERRQ(ierr);
80   }
81   ierr = MatAssemblyBegin(Y,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
82   ierr = MatAssemblyEnd(Y,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
83   PetscFunctionReturn(0);
84 }
85 
86 PetscErrorCode MatAXPY_BasicWithPreallocation(Mat B,Mat Y,PetscScalar a,Mat X,MatStructure str)
87 {
88   PetscInt          i,start,end,j,ncols,m,n;
89   PetscErrorCode    ierr;
90   const PetscInt    *row;
91   PetscScalar       *val;
92   const PetscScalar *vals;
93 
94   PetscFunctionBegin;
95   ierr = MatGetSize(X,&m,&n);CHKERRQ(ierr);
96   ierr = MatGetOwnershipRange(X,&start,&end);CHKERRQ(ierr);
97   if (a == 1.0) {
98     for (i = start; i < end; i++) {
99       ierr = MatGetRow(Y,i,&ncols,&row,&vals);CHKERRQ(ierr);
100       ierr = MatSetValues(B,1,&i,ncols,row,vals,ADD_VALUES);CHKERRQ(ierr);
101       ierr = MatRestoreRow(Y,i,&ncols,&row,&vals);CHKERRQ(ierr);
102 
103       ierr = MatGetRow(X,i,&ncols,&row,&vals);CHKERRQ(ierr);
104       ierr = MatSetValues(B,1,&i,ncols,row,vals,ADD_VALUES);CHKERRQ(ierr);
105       ierr = MatRestoreRow(X,i,&ncols,&row,&vals);CHKERRQ(ierr);
106     }
107   } else {
108     ierr = PetscMalloc1(n+1,&val);CHKERRQ(ierr);
109     for (i=start; i<end; i++) {
110       ierr = MatGetRow(Y,i,&ncols,&row,&vals);CHKERRQ(ierr);
111       ierr = MatSetValues(B,1,&i,ncols,row,vals,ADD_VALUES);CHKERRQ(ierr);
112       ierr = MatRestoreRow(Y,i,&ncols,&row,&vals);CHKERRQ(ierr);
113 
114       ierr = MatGetRow(X,i,&ncols,&row,&vals);CHKERRQ(ierr);
115       for (j=0; j<ncols; j++) {
116         val[j] = a*vals[j];
117       }
118       ierr = MatSetValues(B,1,&i,ncols,row,val,ADD_VALUES);CHKERRQ(ierr);
119       ierr = MatRestoreRow(X,i,&ncols,&row,&vals);CHKERRQ(ierr);
120     }
121     ierr = PetscFree(val);CHKERRQ(ierr);
122   }
123   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
124   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
125   PetscFunctionReturn(0);
126 }
127 
128 /*@
129    MatShift - Computes Y =  Y + a I, where a is a PetscScalar and I is the identity matrix.
130 
131    Neighbor-wise Collective on Mat
132 
133    Input Parameters:
134 +  Y - the matrices
135 -  a - the PetscScalar
136 
137    Level: intermediate
138 
139    Notes: If the matrix Y is missing some diagonal entries this routine can be very slow. To make it fast one should initially
140    fill the matrix so that all diagonal entries have a value (with a value of zero for those locations that would not have an
141    entry).
142 
143    To form Y = Y + diag(V) use MatDiagonalSet()
144 
145    Developers Note: If the local "diagonal part" of the matrix Y has no entries then the local diagonal part is
146     preallocated with 1 nonzero per row for the to be added values. This allows for fast shifting of an empty matrix.
147 
148 .keywords: matrix, add, shift
149 
150 .seealso: MatDiagonalSet(), MatScale(), MatDiagonalScale()
151  @*/
152 PetscErrorCode  MatShift(Mat Y,PetscScalar a)
153 {
154   PetscErrorCode ierr;
155 
156   PetscFunctionBegin;
157   PetscValidHeaderSpecific(Y,MAT_CLASSID,1);
158   if (!Y->assembled) SETERRQ(PetscObjectComm((PetscObject)Y),PETSC_ERR_ARG_WRONGSTATE,"Not for unassembled matrix");
159   if (Y->factortype) SETERRQ(PetscObjectComm((PetscObject)Y),PETSC_ERR_ARG_WRONGSTATE,"Not for factored matrix");
160   MatCheckPreallocated(Y,1);
161 
162   if (Y->ops->shift) {
163     ierr = (*Y->ops->shift)(Y,a);CHKERRQ(ierr);
164   } else {
165     ierr = MatShift_Basic(Y,a);CHKERRQ(ierr);
166   }
167 
168 #if defined(PETSC_HAVE_VIENNACL) || defined(PETSC_HAVE_VECCUDA)
169   if (Y->valid_GPU_matrix != PETSC_OFFLOAD_UNALLOCATED) {
170     Y->valid_GPU_matrix = PETSC_OFFLOAD_CPU;
171   }
172 #endif
173   PetscFunctionReturn(0);
174 }
175 
176 PetscErrorCode  MatDiagonalSet_Default(Mat Y,Vec D,InsertMode is)
177 {
178   PetscErrorCode ierr;
179   PetscInt       i,start,end;
180   PetscScalar    *v;
181 
182   PetscFunctionBegin;
183   ierr = MatGetOwnershipRange(Y,&start,&end);CHKERRQ(ierr);
184   ierr = VecGetArray(D,&v);CHKERRQ(ierr);
185   for (i=start; i<end; i++) {
186     ierr = MatSetValues(Y,1,&i,1,&i,v+i-start,is);CHKERRQ(ierr);
187   }
188   ierr = VecRestoreArray(D,&v);CHKERRQ(ierr);
189   ierr = MatAssemblyBegin(Y,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
190   ierr = MatAssemblyEnd(Y,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
191   PetscFunctionReturn(0);
192 }
193 
194 /*@
195    MatDiagonalSet - Computes Y = Y + D, where D is a diagonal matrix
196    that is represented as a vector. Or Y[i,i] = D[i] if InsertMode is
197    INSERT_VALUES.
198 
199    Input Parameters:
200 +  Y - the input matrix
201 .  D - the diagonal matrix, represented as a vector
202 -  i - INSERT_VALUES or ADD_VALUES
203 
204    Neighbor-wise Collective on Mat and Vec
205 
206    Notes: If the matrix Y is missing some diagonal entries this routine can be very slow. To make it fast one should initially
207    fill the matrix so that all diagonal entries have a value (with a value of zero for those locations that would not have an
208    entry).
209 
210    Level: intermediate
211 
212 .keywords: matrix, add, shift, diagonal
213 
214 .seealso: MatShift(), MatScale(), MatDiagonalScale()
215 @*/
216 PetscErrorCode  MatDiagonalSet(Mat Y,Vec D,InsertMode is)
217 {
218   PetscErrorCode ierr;
219   PetscInt       matlocal,veclocal;
220 
221   PetscFunctionBegin;
222   PetscValidHeaderSpecific(Y,MAT_CLASSID,1);
223   PetscValidHeaderSpecific(D,VEC_CLASSID,2);
224   ierr = MatGetLocalSize(Y,&matlocal,NULL);CHKERRQ(ierr);
225   ierr = VecGetLocalSize(D,&veclocal);CHKERRQ(ierr);
226   if (matlocal != veclocal) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Number local rows of matrix %D does not match that of vector for diagonal %D",matlocal,veclocal);
227   if (Y->ops->diagonalset) {
228     ierr = (*Y->ops->diagonalset)(Y,D,is);CHKERRQ(ierr);
229   } else {
230     ierr = MatDiagonalSet_Default(Y,D,is);CHKERRQ(ierr);
231   }
232   PetscFunctionReturn(0);
233 }
234 
235 /*@
236    MatAYPX - Computes Y = a*Y + X.
237 
238    Logically on Mat
239 
240    Input Parameters:
241 +  a - the PetscScalar multiplier
242 .  Y - the first matrix
243 .  X - the second matrix
244 -  str - either SAME_NONZERO_PATTERN, DIFFERENT_NONZERO_PATTERN or SUBSET_NONZERO_PATTERN
245 
246    Level: intermediate
247 
248 .keywords: matrix, add
249 
250 .seealso: MatAXPY()
251  @*/
252 PetscErrorCode  MatAYPX(Mat Y,PetscScalar a,Mat X,MatStructure str)
253 {
254   PetscScalar    one = 1.0;
255   PetscErrorCode ierr;
256   PetscInt       mX,mY,nX,nY;
257 
258   PetscFunctionBegin;
259   PetscValidHeaderSpecific(X,MAT_CLASSID,3);
260   PetscValidHeaderSpecific(Y,MAT_CLASSID,1);
261   PetscValidLogicalCollectiveScalar(Y,a,2);
262   ierr = MatGetSize(X,&mX,&nX);CHKERRQ(ierr);
263   ierr = MatGetSize(X,&mY,&nY);CHKERRQ(ierr);
264   if (mX != mY || nX != nY) SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Non conforming matrices: %D %D first %D %D second",mX,mY,nX,nY);
265 
266   ierr = MatScale(Y,a);CHKERRQ(ierr);
267   ierr = MatAXPY(Y,one,X,str);CHKERRQ(ierr);
268   PetscFunctionReturn(0);
269 }
270 
271 /*@
272     MatComputeExplicitOperator - Computes the explicit matrix
273 
274     Collective on Mat
275 
276     Input Parameter:
277 .   inmat - the matrix
278 
279     Output Parameter:
280 .   mat - the explict  operator
281 
282     Notes:
283     This computation is done by applying the operators to columns of the
284     identity matrix.
285 
286     Currently, this routine uses a dense matrix format when 1 processor
287     is used and a sparse format otherwise.  This routine is costly in general,
288     and is recommended for use only with relatively small systems.
289 
290     Level: advanced
291 
292 .keywords: Mat, compute, explicit, operator
293 @*/
294 PetscErrorCode  MatComputeExplicitOperator(Mat inmat,Mat *mat)
295 {
296   Vec            in,out;
297   PetscErrorCode ierr;
298   PetscInt       i,m,n,M,N,*rows,start,end;
299   MPI_Comm       comm;
300   PetscScalar    *array,zero = 0.0,one = 1.0;
301   PetscMPIInt    size;
302 
303   PetscFunctionBegin;
304   PetscValidHeaderSpecific(inmat,MAT_CLASSID,1);
305   PetscValidPointer(mat,2);
306 
307   ierr = PetscObjectGetComm((PetscObject)inmat,&comm);CHKERRQ(ierr);
308   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
309 
310   ierr = MatGetLocalSize(inmat,&m,&n);CHKERRQ(ierr);
311   ierr = MatGetSize(inmat,&M,&N);CHKERRQ(ierr);
312   ierr = MatCreateVecs(inmat,&in,&out);CHKERRQ(ierr);
313   ierr = VecSetOption(in,VEC_IGNORE_OFF_PROC_ENTRIES,PETSC_TRUE);CHKERRQ(ierr);
314   ierr = VecGetOwnershipRange(out,&start,&end);CHKERRQ(ierr);
315   ierr = PetscMalloc1(m,&rows);CHKERRQ(ierr);
316   for (i=0; i<m; i++) rows[i] = start + i;
317 
318   ierr = MatCreate(comm,mat);CHKERRQ(ierr);
319   ierr = MatSetSizes(*mat,m,n,M,N);CHKERRQ(ierr);
320   if (size == 1) {
321     ierr = MatSetType(*mat,MATSEQDENSE);CHKERRQ(ierr);
322     ierr = MatSeqDenseSetPreallocation(*mat,NULL);CHKERRQ(ierr);
323   } else {
324     ierr = MatSetType(*mat,MATMPIAIJ);CHKERRQ(ierr);
325     ierr = MatMPIAIJSetPreallocation(*mat,n,NULL,N-n,NULL);CHKERRQ(ierr);
326   }
327 
328   for (i=0; i<N; i++) {
329 
330     ierr = VecSet(in,zero);CHKERRQ(ierr);
331     ierr = VecSetValues(in,1,&i,&one,INSERT_VALUES);CHKERRQ(ierr);
332     ierr = VecAssemblyBegin(in);CHKERRQ(ierr);
333     ierr = VecAssemblyEnd(in);CHKERRQ(ierr);
334 
335     ierr = MatMult(inmat,in,out);CHKERRQ(ierr);
336 
337     ierr = VecGetArray(out,&array);CHKERRQ(ierr);
338     ierr = MatSetValues(*mat,m,rows,1,&i,array,INSERT_VALUES);CHKERRQ(ierr);
339     ierr = VecRestoreArray(out,&array);CHKERRQ(ierr);
340 
341   }
342   ierr = PetscFree(rows);CHKERRQ(ierr);
343   ierr = VecDestroy(&out);CHKERRQ(ierr);
344   ierr = VecDestroy(&in);CHKERRQ(ierr);
345   ierr = MatAssemblyBegin(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
346   ierr = MatAssemblyEnd(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
347   PetscFunctionReturn(0);
348 }
349 
350 /*@
351     MatComputeExplicitOperatorTranspose - Computes the explicit matrix representation of
352         a give matrix that can apply MatMultTranspose()
353 
354     Collective on Mat
355 
356     Input Parameter:
357 .   inmat - the matrix
358 
359     Output Parameter:
360 .   mat - the explict  operator transposed
361 
362     Notes:
363     This computation is done by applying the transpose of the operator to columns of the
364     identity matrix.
365 
366     Currently, this routine uses a dense matrix format when 1 processor
367     is used and a sparse format otherwise.  This routine is costly in general,
368     and is recommended for use only with relatively small systems.
369 
370     Level: advanced
371 
372 .keywords: Mat, compute, explicit, operator
373 @*/
374 PetscErrorCode  MatComputeExplicitOperatorTranspose(Mat inmat,Mat *mat)
375 {
376   Vec            in,out;
377   PetscErrorCode ierr;
378   PetscInt       i,m,n,M,N,*rows,start,end;
379   MPI_Comm       comm;
380   PetscScalar    *array,zero = 0.0,one = 1.0;
381   PetscMPIInt    size;
382 
383   PetscFunctionBegin;
384   PetscValidHeaderSpecific(inmat,MAT_CLASSID,1);
385   PetscValidPointer(mat,2);
386 
387   ierr = PetscObjectGetComm((PetscObject)inmat,&comm);CHKERRQ(ierr);
388   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
389 
390   ierr = MatGetLocalSize(inmat,&m,&n);CHKERRQ(ierr);
391   ierr = MatGetSize(inmat,&M,&N);CHKERRQ(ierr);
392   ierr = MatCreateVecs(inmat,&in,&out);CHKERRQ(ierr);
393   ierr = VecSetOption(in,VEC_IGNORE_OFF_PROC_ENTRIES,PETSC_TRUE);CHKERRQ(ierr);
394   ierr = VecGetOwnershipRange(out,&start,&end);CHKERRQ(ierr);
395   ierr = PetscMalloc1(m,&rows);CHKERRQ(ierr);
396   for (i=0; i<m; i++) rows[i] = start + i;
397 
398   ierr = MatCreate(comm,mat);CHKERRQ(ierr);
399   ierr = MatSetSizes(*mat,m,n,M,N);CHKERRQ(ierr);
400   if (size == 1) {
401     ierr = MatSetType(*mat,MATSEQDENSE);CHKERRQ(ierr);
402     ierr = MatSeqDenseSetPreallocation(*mat,NULL);CHKERRQ(ierr);
403   } else {
404     ierr = MatSetType(*mat,MATMPIAIJ);CHKERRQ(ierr);
405     ierr = MatMPIAIJSetPreallocation(*mat,n,NULL,N-n,NULL);CHKERRQ(ierr);
406   }
407 
408   for (i=0; i<N; i++) {
409 
410     ierr = VecSet(in,zero);CHKERRQ(ierr);
411     ierr = VecSetValues(in,1,&i,&one,INSERT_VALUES);CHKERRQ(ierr);
412     ierr = VecAssemblyBegin(in);CHKERRQ(ierr);
413     ierr = VecAssemblyEnd(in);CHKERRQ(ierr);
414 
415     ierr = MatMultTranspose(inmat,in,out);CHKERRQ(ierr);
416 
417     ierr = VecGetArray(out,&array);CHKERRQ(ierr);
418     ierr = MatSetValues(*mat,m,rows,1,&i,array,INSERT_VALUES);CHKERRQ(ierr);
419     ierr = VecRestoreArray(out,&array);CHKERRQ(ierr);
420 
421   }
422   ierr = PetscFree(rows);CHKERRQ(ierr);
423   ierr = VecDestroy(&out);CHKERRQ(ierr);
424   ierr = VecDestroy(&in);CHKERRQ(ierr);
425   ierr = MatAssemblyBegin(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
426   ierr = MatAssemblyEnd(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
427   PetscFunctionReturn(0);
428 }
429 
430 /*@
431   MatChop - Set all values in the matrix less than the tolerance to zero
432 
433   Input Parameters:
434 + A   - The matrix
435 - tol - The zero tolerance
436 
437   Output Parameters:
438 . A - The chopped matrix
439 
440   Level: intermediate
441 
442 .seealso: MatCreate(), MatZeroEntries()
443  @*/
444 PetscErrorCode MatChop(Mat A, PetscReal tol)
445 {
446   PetscScalar    *newVals;
447   PetscInt       *newCols;
448   PetscInt       rStart, rEnd, numRows, maxRows, r, colMax = 0;
449   PetscErrorCode ierr;
450 
451   PetscFunctionBegin;
452   ierr = MatGetOwnershipRange(A, &rStart, &rEnd);CHKERRQ(ierr);
453   for (r = rStart; r < rEnd; ++r) {
454     PetscInt ncols;
455 
456     ierr   = MatGetRow(A, r, &ncols, NULL, NULL);CHKERRQ(ierr);
457     colMax = PetscMax(colMax, ncols);CHKERRQ(ierr);
458     ierr   = MatRestoreRow(A, r, &ncols, NULL, NULL);CHKERRQ(ierr);
459   }
460   numRows = rEnd - rStart;
461   ierr    = MPIU_Allreduce(&numRows, &maxRows, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
462   ierr    = PetscMalloc2(colMax,&newCols,colMax,&newVals);CHKERRQ(ierr);
463   for (r = rStart; r < rStart+maxRows; ++r) {
464     const PetscScalar *vals;
465     const PetscInt    *cols;
466     PetscInt           ncols, newcols, c;
467 
468     if (r < rEnd) {
469       ierr = MatGetRow(A, r, &ncols, &cols, &vals);CHKERRQ(ierr);
470       for (c = 0; c < ncols; ++c) {
471         newCols[c] = cols[c];
472         newVals[c] = PetscAbsScalar(vals[c]) < tol ? 0.0 : vals[c];
473       }
474       newcols = ncols;
475       ierr = MatRestoreRow(A, r, &ncols, &cols, &vals);CHKERRQ(ierr);
476       ierr = MatSetValues(A, 1, &r, newcols, newCols, newVals, INSERT_VALUES);CHKERRQ(ierr);
477     }
478     ierr = MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
479     ierr = MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
480   }
481   ierr = PetscFree2(newCols,newVals);CHKERRQ(ierr);
482   PetscFunctionReturn(0);
483 }
484