xref: /petsc/src/mat/impls/scatter/mscatter.c (revision d2522c19e8fa9bca20aaca277941d9a63e71db6a)
1 
2 /*
3    This provides a matrix that applies a VecScatter to a vector.
4 */
5 
6 #include <petsc/private/matimpl.h> /*I "petscmat.h" I*/
7 #include <petsc/private/vecimpl.h>
8 
9 typedef struct {
10   VecScatter scatter;
11 } Mat_Scatter;
12 
13 /*@
14     MatScatterGetVecScatter - Returns the user-provided scatter set with MatScatterSetVecScatter()
15 
16     Not Collective, but not cannot use scatter if not used collectively on Mat
17 
18     Input Parameter:
19 .   mat - the matrix, should have been created with MatCreateScatter() or have type MATSCATTER
20 
21     Output Parameter:
22 .   scatter - the scatter context
23 
24     Level: intermediate
25 
26 .seealso: `MatCreateScatter()`, `MatScatterSetVecScatter()`, `MATSCATTER`
27 @*/
28 PetscErrorCode MatScatterGetVecScatter(Mat mat, VecScatter *scatter) {
29   Mat_Scatter *mscatter;
30 
31   PetscFunctionBegin;
32   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
33   PetscValidPointer(scatter, 2);
34   mscatter = (Mat_Scatter *)mat->data;
35   *scatter = mscatter->scatter;
36   PetscFunctionReturn(0);
37 }
38 
39 PetscErrorCode MatDestroy_Scatter(Mat mat) {
40   Mat_Scatter *scatter = (Mat_Scatter *)mat->data;
41 
42   PetscFunctionBegin;
43   PetscCall(VecScatterDestroy(&scatter->scatter));
44   PetscCall(PetscFree(mat->data));
45   PetscFunctionReturn(0);
46 }
47 
48 PetscErrorCode MatMult_Scatter(Mat A, Vec x, Vec y) {
49   Mat_Scatter *scatter = (Mat_Scatter *)A->data;
50 
51   PetscFunctionBegin;
52   PetscCheck(scatter->scatter, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Need to first call MatScatterSetScatter()");
53   PetscCall(VecZeroEntries(y));
54   PetscCall(VecScatterBegin(scatter->scatter, x, y, ADD_VALUES, SCATTER_FORWARD));
55   PetscCall(VecScatterEnd(scatter->scatter, x, y, ADD_VALUES, SCATTER_FORWARD));
56   PetscFunctionReturn(0);
57 }
58 
59 PetscErrorCode MatMultAdd_Scatter(Mat A, Vec x, Vec y, Vec z) {
60   Mat_Scatter *scatter = (Mat_Scatter *)A->data;
61 
62   PetscFunctionBegin;
63   PetscCheck(scatter->scatter, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Need to first call MatScatterSetScatter()");
64   if (z != y) PetscCall(VecCopy(y, z));
65   PetscCall(VecScatterBegin(scatter->scatter, x, z, ADD_VALUES, SCATTER_FORWARD));
66   PetscCall(VecScatterEnd(scatter->scatter, x, z, ADD_VALUES, SCATTER_FORWARD));
67   PetscFunctionReturn(0);
68 }
69 
70 PetscErrorCode MatMultTranspose_Scatter(Mat A, Vec x, Vec y) {
71   Mat_Scatter *scatter = (Mat_Scatter *)A->data;
72 
73   PetscFunctionBegin;
74   PetscCheck(scatter->scatter, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Need to first call MatScatterSetScatter()");
75   PetscCall(VecZeroEntries(y));
76   PetscCall(VecScatterBegin(scatter->scatter, x, y, ADD_VALUES, SCATTER_REVERSE));
77   PetscCall(VecScatterEnd(scatter->scatter, x, y, ADD_VALUES, SCATTER_REVERSE));
78   PetscFunctionReturn(0);
79 }
80 
81 PetscErrorCode MatMultTransposeAdd_Scatter(Mat A, Vec x, Vec y, Vec z) {
82   Mat_Scatter *scatter = (Mat_Scatter *)A->data;
83 
84   PetscFunctionBegin;
85   PetscCheck(scatter->scatter, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Need to first call MatScatterSetScatter()");
86   if (z != y) PetscCall(VecCopy(y, z));
87   PetscCall(VecScatterBegin(scatter->scatter, x, z, ADD_VALUES, SCATTER_REVERSE));
88   PetscCall(VecScatterEnd(scatter->scatter, x, z, ADD_VALUES, SCATTER_REVERSE));
89   PetscFunctionReturn(0);
90 }
91 
92 static struct _MatOps MatOps_Values = {NULL,
93                                        NULL,
94                                        NULL,
95                                        MatMult_Scatter,
96                                        /*  4*/ MatMultAdd_Scatter,
97                                        MatMultTranspose_Scatter,
98                                        MatMultTransposeAdd_Scatter,
99                                        NULL,
100                                        NULL,
101                                        NULL,
102                                        /* 10*/ NULL,
103                                        NULL,
104                                        NULL,
105                                        NULL,
106                                        NULL,
107                                        /* 15*/ NULL,
108                                        NULL,
109                                        NULL,
110                                        NULL,
111                                        NULL,
112                                        /* 20*/ NULL,
113                                        NULL,
114                                        NULL,
115                                        NULL,
116                                        /* 24*/ NULL,
117                                        NULL,
118                                        NULL,
119                                        NULL,
120                                        NULL,
121                                        /* 29*/ NULL,
122                                        NULL,
123                                        NULL,
124                                        NULL,
125                                        NULL,
126                                        /* 34*/ NULL,
127                                        NULL,
128                                        NULL,
129                                        NULL,
130                                        NULL,
131                                        /* 39*/ NULL,
132                                        NULL,
133                                        NULL,
134                                        NULL,
135                                        NULL,
136                                        /* 44*/ NULL,
137                                        NULL,
138                                        MatShift_Basic,
139                                        NULL,
140                                        NULL,
141                                        /* 49*/ NULL,
142                                        NULL,
143                                        NULL,
144                                        NULL,
145                                        NULL,
146                                        /* 54*/ NULL,
147                                        NULL,
148                                        NULL,
149                                        NULL,
150                                        NULL,
151                                        /* 59*/ NULL,
152                                        MatDestroy_Scatter,
153                                        NULL,
154                                        NULL,
155                                        NULL,
156                                        /* 64*/ NULL,
157                                        NULL,
158                                        NULL,
159                                        NULL,
160                                        NULL,
161                                        /* 69*/ NULL,
162                                        NULL,
163                                        NULL,
164                                        NULL,
165                                        NULL,
166                                        /* 74*/ NULL,
167                                        NULL,
168                                        NULL,
169                                        NULL,
170                                        NULL,
171                                        /* 79*/ NULL,
172                                        NULL,
173                                        NULL,
174                                        NULL,
175                                        NULL,
176                                        /* 84*/ NULL,
177                                        NULL,
178                                        NULL,
179                                        NULL,
180                                        NULL,
181                                        /* 89*/ NULL,
182                                        NULL,
183                                        NULL,
184                                        NULL,
185                                        NULL,
186                                        /* 94*/ NULL,
187                                        NULL,
188                                        NULL,
189                                        NULL,
190                                        NULL,
191                                        /*99*/ NULL,
192                                        NULL,
193                                        NULL,
194                                        NULL,
195                                        NULL,
196                                        /*104*/ NULL,
197                                        NULL,
198                                        NULL,
199                                        NULL,
200                                        NULL,
201                                        /*109*/ NULL,
202                                        NULL,
203                                        NULL,
204                                        NULL,
205                                        NULL,
206                                        /*114*/ NULL,
207                                        NULL,
208                                        NULL,
209                                        NULL,
210                                        NULL,
211                                        /*119*/ NULL,
212                                        NULL,
213                                        NULL,
214                                        NULL,
215                                        NULL,
216                                        /*124*/ NULL,
217                                        NULL,
218                                        NULL,
219                                        NULL,
220                                        NULL,
221                                        /*129*/ NULL,
222                                        NULL,
223                                        NULL,
224                                        NULL,
225                                        NULL,
226                                        /*134*/ NULL,
227                                        NULL,
228                                        NULL,
229                                        NULL,
230                                        NULL,
231                                        /*139*/ NULL,
232                                        NULL,
233                                        NULL,
234                                        NULL,
235                                        NULL,
236                                        /*144*/ NULL,
237                                        NULL,
238                                        NULL,
239                                        NULL,
240                                        NULL,
241                                        NULL,
242                                        /*150*/ NULL};
243 
244 /*MC
245    MATSCATTER - MATSCATTER = "scatter" - A matrix type that simply applies a VecScatterBegin/End()
246 
247   Level: advanced
248 
249 .seealso: `MatCreateScatter()`, `MatScatterSetVecScatter()`, `MatScatterGetVecScatter()`
250 
251 M*/
252 
253 PETSC_EXTERN PetscErrorCode MatCreate_Scatter(Mat A) {
254   Mat_Scatter *b;
255 
256   PetscFunctionBegin;
257   PetscCall(PetscMemcpy(A->ops, &MatOps_Values, sizeof(struct _MatOps)));
258   PetscCall(PetscNewLog(A, &b));
259 
260   A->data = (void *)b;
261 
262   PetscCall(PetscLayoutSetUp(A->rmap));
263   PetscCall(PetscLayoutSetUp(A->cmap));
264 
265   A->assembled    = PETSC_TRUE;
266   A->preallocated = PETSC_FALSE;
267 
268   PetscCall(PetscObjectChangeTypeName((PetscObject)A, MATSCATTER));
269   PetscFunctionReturn(0);
270 }
271 
272 #include <petsc/private/sfimpl.h>
273 /*@C
274    MatCreateScatter - Creates a new matrix based on a VecScatter
275 
276   Collective
277 
278    Input Parameters:
279 +  comm - MPI communicator
280 -  scatter - a VecScatterContext
281 
282    Output Parameter:
283 .  A - the matrix
284 
285    Level: intermediate
286 
287    PETSc requires that matrices and vectors being used for certain
288    operations are partitioned accordingly.  For example, when
289    creating a scatter matrix, A, that supports parallel matrix-vector
290    products using MatMult(A,x,y) the user should set the number
291    of local matrix rows to be the number of local elements of the
292    corresponding result vector, y. Note that this is information is
293    required for use of the matrix interface routines, even though
294    the scatter matrix may not actually be physically partitioned.
295 
296   Developer Notes: This directly accesses information inside the VecScatter associated with the matrix-vector product
297    for this matrix. This is not desirable..
298 
299 .seealso: `MatScatterSetVecScatter()`, `MatScatterGetVecScatter()`, `MATSCATTER`
300 @*/
301 PetscErrorCode MatCreateScatter(MPI_Comm comm, VecScatter scatter, Mat *A) {
302   PetscFunctionBegin;
303   PetscCall(MatCreate(comm, A));
304   PetscCall(MatSetSizes(*A, scatter->vscat.to_n, scatter->vscat.from_n, PETSC_DETERMINE, PETSC_DETERMINE));
305   PetscCall(MatSetType(*A, MATSCATTER));
306   PetscCall(MatScatterSetVecScatter(*A, scatter));
307   PetscCall(MatSetUp(*A));
308   PetscFunctionReturn(0);
309 }
310 
311 /*@
312     MatScatterSetVecScatter - sets that scatter that the matrix is to apply as its linear operator
313 
314    Collective on Mat
315 
316     Input Parameters:
317 +   mat - the scatter matrix
318 -   scatter - the scatter context create with VecScatterCreate()
319 
320    Level: advanced
321 
322 .seealso: `MatCreateScatter()`, `MATSCATTER`
323 @*/
324 PetscErrorCode MatScatterSetVecScatter(Mat mat, VecScatter scatter) {
325   Mat_Scatter *mscatter = (Mat_Scatter *)mat->data;
326 
327   PetscFunctionBegin;
328   PetscValidHeaderSpecific(mat, MAT_CLASSID, 1);
329   PetscValidHeaderSpecific(scatter, PETSCSF_CLASSID, 2);
330   PetscCheckSameComm((PetscObject)scatter, 2, (PetscObject)mat, 1);
331   PetscCheck(mat->rmap->n == scatter->vscat.to_n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Number of local rows in matrix %" PetscInt_FMT " not equal local scatter size %" PetscInt_FMT, mat->rmap->n, scatter->vscat.to_n);
332   PetscCheck(mat->cmap->n == scatter->vscat.from_n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Number of local columns in matrix %" PetscInt_FMT " not equal local scatter size %" PetscInt_FMT, mat->cmap->n, scatter->vscat.from_n);
333 
334   PetscCall(PetscObjectReference((PetscObject)scatter));
335   PetscCall(VecScatterDestroy(&mscatter->scatter));
336 
337   mscatter->scatter = scatter;
338   PetscFunctionReturn(0);
339 }
340