1 /*
2 Code for manipulating distributed regular arrays in parallel.
3 */
4
5 #include <petsc/private/dmdaimpl.h> /*I "petscdmda.h" I*/
6
7 /*
8 DMLocalToLocalCreate_DA - Creates the local to local scatter
9
10 Collective
11
12 Input Parameter:
13 . da - the `DMDA`
14
15 */
DMLocalToLocalCreate_DA(DM da)16 PetscErrorCode DMLocalToLocalCreate_DA(DM da)
17 {
18 PetscInt *idx, left, j, count, up, down, i, bottom, top, k, dim = da->dim;
19 DM_DA *dd = (DM_DA *)da->data;
20
21 PetscFunctionBegin;
22 PetscValidHeaderSpecific(da, DM_CLASSID, 1);
23
24 if (dd->ltol) PetscFunctionReturn(PETSC_SUCCESS);
25 /*
26 We simply remap the values in the from part of
27 global to local to read from an array with the ghost values
28 rather than from the plain array.
29 */
30 PetscCall(VecScatterCopy(dd->gtol, &dd->ltol));
31 if (dim == 1) {
32 left = dd->xs - dd->Xs;
33 PetscCall(PetscMalloc1(dd->xe - dd->xs, &idx));
34 for (j = 0; j < dd->xe - dd->xs; j++) idx[j] = left + j;
35 } else if (dim == 2) {
36 left = dd->xs - dd->Xs;
37 down = dd->ys - dd->Ys;
38 up = down + dd->ye - dd->ys;
39 PetscCall(PetscMalloc1((dd->xe - dd->xs) * (up - down), &idx));
40 count = 0;
41 for (i = down; i < up; i++) {
42 for (j = 0; j < dd->xe - dd->xs; j++) idx[count++] = left + i * (dd->Xe - dd->Xs) + j;
43 }
44 } else if (dim == 3) {
45 left = dd->xs - dd->Xs;
46 bottom = dd->ys - dd->Ys;
47 top = bottom + dd->ye - dd->ys;
48 down = dd->zs - dd->Zs;
49 up = down + dd->ze - dd->zs;
50 count = (dd->xe - dd->xs) * (top - bottom) * (up - down);
51 PetscCall(PetscMalloc1(count, &idx));
52 count = 0;
53 for (i = down; i < up; i++) {
54 for (j = bottom; j < top; j++) {
55 for (k = 0; k < dd->xe - dd->xs; k++) idx[count++] = (left + j * (dd->Xe - dd->Xs)) + i * (dd->Xe - dd->Xs) * (dd->Ye - dd->Ys) + k;
56 }
57 }
58 } else SETERRQ(PetscObjectComm((PetscObject)da), PETSC_ERR_ARG_CORRUPT, "DMDA has invalid dimension %" PetscInt_FMT, dim);
59
60 PetscCall(VecScatterRemap(dd->ltol, idx, NULL));
61 PetscCall(PetscFree(idx));
62 PetscFunctionReturn(PETSC_SUCCESS);
63 }
64
DMLocalToLocalBegin_DA(DM da,Vec g,InsertMode mode,Vec l)65 PetscErrorCode DMLocalToLocalBegin_DA(DM da, Vec g, InsertMode mode, Vec l)
66 {
67 DM_DA *dd = (DM_DA *)da->data;
68
69 PetscFunctionBegin;
70 PetscValidHeaderSpecific(da, DM_CLASSID, 1);
71 if (!dd->ltol) PetscCall(DMLocalToLocalCreate_DA(da));
72 PetscCall(VecScatterBegin(dd->ltol, g, l, mode, SCATTER_FORWARD));
73 PetscFunctionReturn(PETSC_SUCCESS);
74 }
75
DMLocalToLocalEnd_DA(DM da,Vec g,InsertMode mode,Vec l)76 PetscErrorCode DMLocalToLocalEnd_DA(DM da, Vec g, InsertMode mode, Vec l)
77 {
78 DM_DA *dd = (DM_DA *)da->data;
79
80 PetscFunctionBegin;
81 PetscValidHeaderSpecific(da, DM_CLASSID, 1);
82 PetscValidHeaderSpecific(g, VEC_CLASSID, 2);
83 PetscCall(VecScatterEnd(dd->ltol, g, l, mode, SCATTER_FORWARD));
84 PetscFunctionReturn(PETSC_SUCCESS);
85 }
86