xref: /petsc/src/mat/impls/scatter/mscatter.c (revision 2d30e087755efd99e28fdfe792ffbeb2ee1ea928)
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()` in a `MATSCATTER` matrix
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: `MATSCATTER`, `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()` and `VecScatterEnd()`
246 
247   Level: advanced
248 
249 .seealso: ``MATSCATTER`, MatCreateScatter()`, `MatScatterSetVecScatter()`, `MatScatterGetVecScatter()`
250 M*/
251 
252 PETSC_EXTERN PetscErrorCode MatCreate_Scatter(Mat A) {
253   Mat_Scatter *b;
254 
255   PetscFunctionBegin;
256   PetscCall(PetscMemcpy(A->ops, &MatOps_Values, sizeof(struct _MatOps)));
257   PetscCall(PetscNewLog(A, &b));
258 
259   A->data = (void *)b;
260 
261   PetscCall(PetscLayoutSetUp(A->rmap));
262   PetscCall(PetscLayoutSetUp(A->cmap));
263 
264   A->assembled    = PETSC_TRUE;
265   A->preallocated = PETSC_FALSE;
266 
267   PetscCall(PetscObjectChangeTypeName((PetscObject)A, MATSCATTER));
268   PetscFunctionReturn(0);
269 }
270 
271 #include <petsc/private/sfimpl.h>
272 /*@C
273    MatCreateScatter - Creates a new matrix of `MatType` `MATSCATTER`, based on a VecScatter
274 
275   Collective
276 
277    Input Parameters:
278 +  comm - MPI communicator
279 -  scatter - a `VecScatter`
280 
281    Output Parameter:
282 .  A - the matrix
283 
284    Level: intermediate
285 
286    PETSc requires that matrices and vectors being used for certain
287    operations are partitioned accordingly.  For example, when
288    creating a scatter matrix, A, that supports parallel matrix-vector
289    products using `MatMult`(A,x,y) the user should set the number
290    of local matrix rows to be the number of local elements of the
291    corresponding result vector, y. Note that this is information is
292    required for use of the matrix interface routines, even though
293    the scatter matrix may not actually be physically partitioned.
294 
295   Developer Note:
296    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 the scatter that the matrix is to apply as its linear operator in a `MATSCATTER`
313 
314    Collective on mat
315 
316     Input Parameters:
317 +   mat - the `MATSCATTER` matrix
318 -   scatter - the scatter context create with `VecScatterCreate()`
319 
320    Level: advanced
321 
322 .seealso: `MATSCATTER`, `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