xref: /petsc/src/mat/impls/scatter/mscatter.c (revision 28b400f66ebc7ae0049166a2294dfcd3df27e64b)
12a6744ebSBarry Smith 
22a6744ebSBarry Smith /*
32a6744ebSBarry Smith    This provides a matrix that applies a VecScatter to a vector.
42a6744ebSBarry Smith */
52a6744ebSBarry Smith 
6af0996ceSBarry Smith #include <petsc/private/matimpl.h>        /*I "petscmat.h" I*/
7af0996ceSBarry Smith #include <petsc/private/vecimpl.h>
82a6744ebSBarry Smith 
92a6744ebSBarry Smith typedef struct {
102a6744ebSBarry Smith   VecScatter scatter;
112a6744ebSBarry Smith } Mat_Scatter;
122a6744ebSBarry Smith 
132a6744ebSBarry Smith /*@
142a6744ebSBarry Smith     MatScatterGetVecScatter - Returns the user-provided scatter set with MatScatterSetVecScatter()
152a6744ebSBarry Smith 
162a6744ebSBarry Smith     Not Collective, but not cannot use scatter if not used collectively on Mat
172a6744ebSBarry Smith 
182a6744ebSBarry Smith     Input Parameter:
192a6744ebSBarry Smith .   mat - the matrix, should have been created with MatCreateScatter() or have type MATSCATTER
202a6744ebSBarry Smith 
212a6744ebSBarry Smith     Output Parameter:
222a6744ebSBarry Smith .   scatter - the scatter context
232a6744ebSBarry Smith 
242a6744ebSBarry Smith     Level: intermediate
252a6744ebSBarry Smith 
262a6744ebSBarry Smith .seealso: MatCreateScatter(), MatScatterSetVecScatter(), MATSCATTER
272a6744ebSBarry Smith @*/
287087cfbeSBarry Smith PetscErrorCode  MatScatterGetVecScatter(Mat mat,VecScatter *scatter)
292a6744ebSBarry Smith {
302a6744ebSBarry Smith   Mat_Scatter *mscatter;
312a6744ebSBarry Smith 
322a6744ebSBarry Smith   PetscFunctionBegin;
330700a824SBarry Smith   PetscValidHeaderSpecific(mat,MAT_CLASSID,1);
342a6744ebSBarry Smith   PetscValidPointer(scatter,2);
352a6744ebSBarry Smith   mscatter = (Mat_Scatter*)mat->data;
362a6744ebSBarry Smith   *scatter = mscatter->scatter;
372a6744ebSBarry Smith   PetscFunctionReturn(0);
382a6744ebSBarry Smith }
392a6744ebSBarry Smith 
402a6744ebSBarry Smith PetscErrorCode MatDestroy_Scatter(Mat mat)
412a6744ebSBarry Smith {
422a6744ebSBarry Smith   Mat_Scatter    *scatter = (Mat_Scatter*)mat->data;
432a6744ebSBarry Smith 
442a6744ebSBarry Smith   PetscFunctionBegin;
455f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterDestroy(&scatter->scatter));
465f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscFree(mat->data));
472a6744ebSBarry Smith   PetscFunctionReturn(0);
482a6744ebSBarry Smith }
492a6744ebSBarry Smith 
502a6744ebSBarry Smith PetscErrorCode MatMult_Scatter(Mat A,Vec x,Vec y)
512a6744ebSBarry Smith {
522a6744ebSBarry Smith   Mat_Scatter    *scatter = (Mat_Scatter*)A->data;
532a6744ebSBarry Smith 
542a6744ebSBarry Smith   PetscFunctionBegin;
55*28b400f6SJacob Faibussowitsch   PetscCheck(scatter->scatter,PetscObjectComm((PetscObject)A),PETSC_ERR_ARG_WRONGSTATE,"Need to first call MatScatterSetScatter()");
565f80ce2aSJacob Faibussowitsch   CHKERRQ(VecZeroEntries(y));
575f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterBegin(scatter->scatter,x,y,ADD_VALUES,SCATTER_FORWARD));
585f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterEnd(scatter->scatter,x,y,ADD_VALUES,SCATTER_FORWARD));
592a6744ebSBarry Smith   PetscFunctionReturn(0);
602a6744ebSBarry Smith }
612a6744ebSBarry Smith 
622a6744ebSBarry Smith PetscErrorCode MatMultAdd_Scatter(Mat A,Vec x,Vec y,Vec z)
632a6744ebSBarry Smith {
642a6744ebSBarry Smith   Mat_Scatter    *scatter = (Mat_Scatter*)A->data;
652a6744ebSBarry Smith 
662a6744ebSBarry Smith   PetscFunctionBegin;
67*28b400f6SJacob Faibussowitsch   PetscCheck(scatter->scatter,PetscObjectComm((PetscObject)A),PETSC_ERR_ARG_WRONGSTATE,"Need to first call MatScatterSetScatter()");
685f80ce2aSJacob Faibussowitsch   if (z != y) CHKERRQ(VecCopy(y,z));
695f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterBegin(scatter->scatter,x,z,ADD_VALUES,SCATTER_FORWARD));
705f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterEnd(scatter->scatter,x,z,ADD_VALUES,SCATTER_FORWARD));
712a6744ebSBarry Smith   PetscFunctionReturn(0);
722a6744ebSBarry Smith }
732a6744ebSBarry Smith 
742a6744ebSBarry Smith PetscErrorCode MatMultTranspose_Scatter(Mat A,Vec x,Vec y)
752a6744ebSBarry Smith {
762a6744ebSBarry Smith   Mat_Scatter    *scatter = (Mat_Scatter*)A->data;
772a6744ebSBarry Smith 
782a6744ebSBarry Smith   PetscFunctionBegin;
79*28b400f6SJacob Faibussowitsch   PetscCheck(scatter->scatter,PetscObjectComm((PetscObject)A),PETSC_ERR_ARG_WRONGSTATE,"Need to first call MatScatterSetScatter()");
805f80ce2aSJacob Faibussowitsch   CHKERRQ(VecZeroEntries(y));
815f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterBegin(scatter->scatter,x,y,ADD_VALUES,SCATTER_REVERSE));
825f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterEnd(scatter->scatter,x,y,ADD_VALUES,SCATTER_REVERSE));
832a6744ebSBarry Smith   PetscFunctionReturn(0);
842a6744ebSBarry Smith }
852a6744ebSBarry Smith 
862a6744ebSBarry Smith PetscErrorCode MatMultTransposeAdd_Scatter(Mat A,Vec x,Vec y,Vec z)
872a6744ebSBarry Smith {
882a6744ebSBarry Smith   Mat_Scatter    *scatter = (Mat_Scatter*)A->data;
892a6744ebSBarry Smith 
902a6744ebSBarry Smith   PetscFunctionBegin;
91*28b400f6SJacob Faibussowitsch   PetscCheck(scatter->scatter,PetscObjectComm((PetscObject)A),PETSC_ERR_ARG_WRONGSTATE,"Need to first call MatScatterSetScatter()");
925f80ce2aSJacob Faibussowitsch   if (z != y) CHKERRQ(VecCopy(y,z));
935f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterBegin(scatter->scatter,x,z,ADD_VALUES,SCATTER_REVERSE));
945f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterEnd(scatter->scatter,x,z,ADD_VALUES,SCATTER_REVERSE));
952a6744ebSBarry Smith   PetscFunctionReturn(0);
962a6744ebSBarry Smith }
972a6744ebSBarry Smith 
98f4259b30SLisandro Dalcin static struct _MatOps MatOps_Values = {NULL,
99f4259b30SLisandro Dalcin                                        NULL,
100f4259b30SLisandro Dalcin                                        NULL,
1012a6744ebSBarry Smith                                        MatMult_Scatter,
1022a6744ebSBarry Smith                                /*  4*/ MatMultAdd_Scatter,
1032a6744ebSBarry Smith                                        MatMultTranspose_Scatter,
1042a6744ebSBarry Smith                                        MatMultTransposeAdd_Scatter,
105f4259b30SLisandro Dalcin                                        NULL,
106f4259b30SLisandro Dalcin                                        NULL,
107f4259b30SLisandro Dalcin                                        NULL,
108f4259b30SLisandro Dalcin                                /* 10*/ NULL,
109f4259b30SLisandro Dalcin                                        NULL,
110f4259b30SLisandro Dalcin                                        NULL,
111f4259b30SLisandro Dalcin                                        NULL,
112f4259b30SLisandro Dalcin                                        NULL,
113f4259b30SLisandro Dalcin                                /* 15*/ NULL,
114f4259b30SLisandro Dalcin                                        NULL,
115f4259b30SLisandro Dalcin                                        NULL,
116f4259b30SLisandro Dalcin                                        NULL,
117f4259b30SLisandro Dalcin                                        NULL,
118f4259b30SLisandro Dalcin                                /* 20*/ NULL,
119f4259b30SLisandro Dalcin                                        NULL,
120f4259b30SLisandro Dalcin                                        NULL,
121f4259b30SLisandro Dalcin                                        NULL,
122f4259b30SLisandro Dalcin                                /* 24*/ NULL,
123f4259b30SLisandro Dalcin                                        NULL,
124f4259b30SLisandro Dalcin                                        NULL,
125f4259b30SLisandro Dalcin                                        NULL,
126f4259b30SLisandro Dalcin                                        NULL,
127f4259b30SLisandro Dalcin                                /* 29*/ NULL,
128f4259b30SLisandro Dalcin                                        NULL,
129f4259b30SLisandro Dalcin                                        NULL,
130f4259b30SLisandro Dalcin                                        NULL,
131f4259b30SLisandro Dalcin                                        NULL,
132f4259b30SLisandro Dalcin                                /* 34*/ NULL,
133f4259b30SLisandro Dalcin                                        NULL,
134f4259b30SLisandro Dalcin                                        NULL,
135f4259b30SLisandro Dalcin                                        NULL,
136f4259b30SLisandro Dalcin                                        NULL,
137f4259b30SLisandro Dalcin                                /* 39*/ NULL,
138f4259b30SLisandro Dalcin                                        NULL,
139f4259b30SLisandro Dalcin                                        NULL,
140f4259b30SLisandro Dalcin                                        NULL,
141f4259b30SLisandro Dalcin                                        NULL,
142f4259b30SLisandro Dalcin                                /* 44*/ NULL,
143f4259b30SLisandro Dalcin                                        NULL,
1447d68702bSBarry Smith                                        MatShift_Basic,
145f4259b30SLisandro Dalcin                                        NULL,
146f4259b30SLisandro Dalcin                                        NULL,
147f4259b30SLisandro Dalcin                                /* 49*/ NULL,
148f4259b30SLisandro Dalcin                                        NULL,
149f4259b30SLisandro Dalcin                                        NULL,
150f4259b30SLisandro Dalcin                                        NULL,
151f4259b30SLisandro Dalcin                                        NULL,
152f4259b30SLisandro Dalcin                                /* 54*/ NULL,
153f4259b30SLisandro Dalcin                                        NULL,
154f4259b30SLisandro Dalcin                                        NULL,
155f4259b30SLisandro Dalcin                                        NULL,
156f4259b30SLisandro Dalcin                                        NULL,
157f4259b30SLisandro Dalcin                                /* 59*/ NULL,
1582a6744ebSBarry Smith                                        MatDestroy_Scatter,
159f4259b30SLisandro Dalcin                                        NULL,
160f4259b30SLisandro Dalcin                                        NULL,
161f4259b30SLisandro Dalcin                                        NULL,
162f4259b30SLisandro Dalcin                                /* 64*/ NULL,
163f4259b30SLisandro Dalcin                                        NULL,
164f4259b30SLisandro Dalcin                                        NULL,
165f4259b30SLisandro Dalcin                                        NULL,
166f4259b30SLisandro Dalcin                                        NULL,
167f4259b30SLisandro Dalcin                                /* 69*/ NULL,
168f4259b30SLisandro Dalcin                                        NULL,
169f4259b30SLisandro Dalcin                                        NULL,
170f4259b30SLisandro Dalcin                                        NULL,
171f4259b30SLisandro Dalcin                                        NULL,
172f4259b30SLisandro Dalcin                                /* 74*/ NULL,
173f4259b30SLisandro Dalcin                                        NULL,
174f4259b30SLisandro Dalcin                                        NULL,
175f4259b30SLisandro Dalcin                                        NULL,
176f4259b30SLisandro Dalcin                                        NULL,
177f4259b30SLisandro Dalcin                                /* 79*/ NULL,
178f4259b30SLisandro Dalcin                                        NULL,
179f4259b30SLisandro Dalcin                                        NULL,
180f4259b30SLisandro Dalcin                                        NULL,
181f4259b30SLisandro Dalcin                                        NULL,
182f4259b30SLisandro Dalcin                                /* 84*/ NULL,
183f4259b30SLisandro Dalcin                                        NULL,
184f4259b30SLisandro Dalcin                                        NULL,
185f4259b30SLisandro Dalcin                                        NULL,
186f4259b30SLisandro Dalcin                                        NULL,
187f4259b30SLisandro Dalcin                                /* 89*/ NULL,
188f4259b30SLisandro Dalcin                                        NULL,
189f4259b30SLisandro Dalcin                                        NULL,
190f4259b30SLisandro Dalcin                                        NULL,
191f4259b30SLisandro Dalcin                                        NULL,
192f4259b30SLisandro Dalcin                                /* 94*/ NULL,
193f4259b30SLisandro Dalcin                                        NULL,
194f4259b30SLisandro Dalcin                                        NULL,
195f4259b30SLisandro Dalcin                                        NULL,
196f4259b30SLisandro Dalcin                                        NULL,
197f4259b30SLisandro Dalcin                                 /*99*/ NULL,
198f4259b30SLisandro Dalcin                                        NULL,
199f4259b30SLisandro Dalcin                                        NULL,
200f4259b30SLisandro Dalcin                                        NULL,
201f4259b30SLisandro Dalcin                                        NULL,
202f4259b30SLisandro Dalcin                                /*104*/ NULL,
203f4259b30SLisandro Dalcin                                        NULL,
204f4259b30SLisandro Dalcin                                        NULL,
205f4259b30SLisandro Dalcin                                        NULL,
206f4259b30SLisandro Dalcin                                        NULL,
207f4259b30SLisandro Dalcin                                /*109*/ NULL,
208f4259b30SLisandro Dalcin                                        NULL,
209f4259b30SLisandro Dalcin                                        NULL,
210f4259b30SLisandro Dalcin                                        NULL,
211f4259b30SLisandro Dalcin                                        NULL,
212f4259b30SLisandro Dalcin                                /*114*/ NULL,
213f4259b30SLisandro Dalcin                                        NULL,
214f4259b30SLisandro Dalcin                                        NULL,
215f4259b30SLisandro Dalcin                                        NULL,
216f4259b30SLisandro Dalcin                                        NULL,
217f4259b30SLisandro Dalcin                                /*119*/ NULL,
218f4259b30SLisandro Dalcin                                        NULL,
219f4259b30SLisandro Dalcin                                        NULL,
220f4259b30SLisandro Dalcin                                        NULL,
221f4259b30SLisandro Dalcin                                        NULL,
222f4259b30SLisandro Dalcin                                /*124*/ NULL,
223f4259b30SLisandro Dalcin                                        NULL,
224f4259b30SLisandro Dalcin                                        NULL,
225f4259b30SLisandro Dalcin                                        NULL,
226f4259b30SLisandro Dalcin                                        NULL,
227f4259b30SLisandro Dalcin                                /*129*/ NULL,
228f4259b30SLisandro Dalcin                                        NULL,
229f4259b30SLisandro Dalcin                                        NULL,
230f4259b30SLisandro Dalcin                                        NULL,
231f4259b30SLisandro Dalcin                                        NULL,
232f4259b30SLisandro Dalcin                                /*134*/ NULL,
233f4259b30SLisandro Dalcin                                        NULL,
234f4259b30SLisandro Dalcin                                        NULL,
235f4259b30SLisandro Dalcin                                        NULL,
236f4259b30SLisandro Dalcin                                        NULL,
237f4259b30SLisandro Dalcin                                 /*139*/NULL,
238d70f29a3SPierre Jolivet                                        NULL,
239d70f29a3SPierre Jolivet                                        NULL,
240d70f29a3SPierre Jolivet                                        NULL,
241d70f29a3SPierre Jolivet                                        NULL,
242d70f29a3SPierre Jolivet                                 /*144*/NULL,
243d70f29a3SPierre Jolivet                                        NULL,
244f4259b30SLisandro Dalcin                                        NULL,
245f4259b30SLisandro Dalcin                                        NULL
2463964eb88SJed Brown };
2472a6744ebSBarry Smith 
2482a6744ebSBarry Smith /*MC
2494a440b9bSBarry Smith    MATSCATTER - MATSCATTER = "scatter" - A matrix type that simply applies a VecScatterBegin/End()
2502a6744ebSBarry Smith 
2512a6744ebSBarry Smith   Level: advanced
2522a6744ebSBarry Smith 
2532a6744ebSBarry Smith .seealso: MatCreateScatter(), MatScatterSetVecScatter(), MatScatterGetVecScatter()
2542a6744ebSBarry Smith 
2552a6744ebSBarry Smith M*/
2562a6744ebSBarry Smith 
2578cc058d9SJed Brown PETSC_EXTERN PetscErrorCode MatCreate_Scatter(Mat A)
2582a6744ebSBarry Smith {
2592a6744ebSBarry Smith   Mat_Scatter    *b;
2602a6744ebSBarry Smith 
2612a6744ebSBarry Smith   PetscFunctionBegin;
2625f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscMemcpy(A->ops,&MatOps_Values,sizeof(struct _MatOps)));
2635f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscNewLog(A,&b));
2642a6744ebSBarry Smith 
2652a6744ebSBarry Smith   A->data = (void*)b;
2662a6744ebSBarry Smith 
2675f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscLayoutSetUp(A->rmap));
2685f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscLayoutSetUp(A->cmap));
2692a6744ebSBarry Smith 
2702a6744ebSBarry Smith   A->assembled    = PETSC_TRUE;
2712a6744ebSBarry Smith   A->preallocated = PETSC_FALSE;
27274d95942SJed Brown 
2735f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscObjectChangeTypeName((PetscObject)A,MATSCATTER));
2742a6744ebSBarry Smith   PetscFunctionReturn(0);
2752a6744ebSBarry Smith }
2762a6744ebSBarry Smith 
27797929ea7SJunchao Zhang #include <petsc/private/sfimpl.h>
2782a6744ebSBarry Smith /*@C
2792a6744ebSBarry Smith    MatCreateScatter - Creates a new matrix based on a VecScatter
2802a6744ebSBarry Smith 
281d083f849SBarry Smith   Collective
2822a6744ebSBarry Smith 
2832a6744ebSBarry Smith    Input Parameters:
2842a6744ebSBarry Smith +  comm - MPI communicator
2852a6744ebSBarry Smith -  scatter - a VecScatterContext
2862a6744ebSBarry Smith 
2872a6744ebSBarry Smith    Output Parameter:
2882a6744ebSBarry Smith .  A - the matrix
2892a6744ebSBarry Smith 
2902a6744ebSBarry Smith    Level: intermediate
2912a6744ebSBarry Smith 
2922a6744ebSBarry Smith    PETSc requires that matrices and vectors being used for certain
2932a6744ebSBarry Smith    operations are partitioned accordingly.  For example, when
2942a6744ebSBarry Smith    creating a scatter matrix, A, that supports parallel matrix-vector
2952a6744ebSBarry Smith    products using MatMult(A,x,y) the user should set the number
2962a6744ebSBarry Smith    of local matrix rows to be the number of local elements of the
2972a6744ebSBarry Smith    corresponding result vector, y. Note that this is information is
2982a6744ebSBarry Smith    required for use of the matrix interface routines, even though
2992a6744ebSBarry Smith    the scatter matrix may not actually be physically partitioned.
3002a6744ebSBarry Smith 
3016eb45d04SBarry Smith   Developer Notes: This directly accesses information inside the VecScatter associated with the matrix-vector product
3026eb45d04SBarry Smith    for this matrix. This is not desirable..
3036eb45d04SBarry Smith 
3042a6744ebSBarry Smith .seealso: MatScatterSetVecScatter(), MatScatterGetVecScatter(), MATSCATTER
3052a6744ebSBarry Smith @*/
3067087cfbeSBarry Smith PetscErrorCode  MatCreateScatter(MPI_Comm comm,VecScatter scatter,Mat *A)
3072a6744ebSBarry Smith {
3082a6744ebSBarry Smith   PetscFunctionBegin;
3095f80ce2aSJacob Faibussowitsch   CHKERRQ(MatCreate(comm,A));
3105f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetSizes(*A,scatter->vscat.to_n,scatter->vscat.from_n,PETSC_DETERMINE,PETSC_DETERMINE));
3115f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetType(*A,MATSCATTER));
3125f80ce2aSJacob Faibussowitsch   CHKERRQ(MatScatterSetVecScatter(*A,scatter));
3135f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetUp(*A));
3142a6744ebSBarry Smith   PetscFunctionReturn(0);
3152a6744ebSBarry Smith }
3162a6744ebSBarry Smith 
3172a6744ebSBarry Smith /*@
3182a6744ebSBarry Smith     MatScatterSetVecScatter - sets that scatter that the matrix is to apply as its linear operator
3192a6744ebSBarry Smith 
3202a6744ebSBarry Smith    Collective on Mat
3212a6744ebSBarry Smith 
3222a6744ebSBarry Smith     Input Parameters:
3232a6744ebSBarry Smith +   mat - the scatter matrix
3249448b7f1SJunchao Zhang -   scatter - the scatter context create with VecScatterCreate()
3252a6744ebSBarry Smith 
3262a6744ebSBarry Smith    Level: advanced
3272a6744ebSBarry Smith 
3282a6744ebSBarry Smith .seealso: MatCreateScatter(), MATSCATTER
3292a6744ebSBarry Smith @*/
3307087cfbeSBarry Smith PetscErrorCode  MatScatterSetVecScatter(Mat mat,VecScatter scatter)
3312a6744ebSBarry Smith {
3322a6744ebSBarry Smith   Mat_Scatter    *mscatter = (Mat_Scatter*)mat->data;
3332a6744ebSBarry Smith 
3342a6744ebSBarry Smith   PetscFunctionBegin;
3350700a824SBarry Smith   PetscValidHeaderSpecific(mat,MAT_CLASSID,1);
33697929ea7SJunchao Zhang   PetscValidHeaderSpecific(scatter,PETSCSF_CLASSID,2);
337064a246eSJacob Faibussowitsch   PetscCheckSameComm((PetscObject)scatter,2,(PetscObject)mat,1);
3382c71b3e2SJacob Faibussowitsch   PetscCheckFalse(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);
3392c71b3e2SJacob Faibussowitsch   PetscCheckFalse(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);
3402a6744ebSBarry Smith 
3415f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscObjectReference((PetscObject)scatter));
3425f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScatterDestroy(&mscatter->scatter));
34326fbe8dcSKarl Rupp 
3442a6744ebSBarry Smith   mscatter->scatter = scatter;
3452a6744ebSBarry Smith   PetscFunctionReturn(0);
3462a6744ebSBarry Smith }
347