Actual source code: daghost.c
3: Code for manipulating distributed regular arrays in parallel.
6: #include <petsc/private/dmdaimpl.h>
9: DMDAGetGhostCorners - Returns the global (x,y,z) indices of the lower left
10: corner and size of the local region, including ghost points.
12: Not Collective
14: Input Parameter:
15: . da - the distributed array
17: Output Parameters:
18: + x,y,z - the corner indices (where y and z are optional; these are used
19: for 2D and 3D problems)
20: - m,n,p - widths in the corresponding directions (where n and p are optional;
21: these are used for 2D and 3D problems)
23: Level: beginner
26: The corner information is independent of the number of degrees of
27: freedom per node set with the DMDACreateXX() routine. Thus the x, y, z, and
28: m, n, p can be thought of as coordinates on a logical grid, where each
29: grid point has (potentially) several degrees of freedom.
30: Any of y, z, n, and p can be passed in as NULL if not needed.
32: .keywords: distributed array, get, ghost, corners, nodes, local indices
34: .seealso: DMDAGetCorners(), DMDACreate1d(), DMDACreate2d(), DMDACreate3d(), DMDAGetOwnershipRanges()
37: PetscErrorCode DMDAGetGhostCorners(DM da,PetscInt *x,PetscInt *y,PetscInt *z,PetscInt *m,PetscInt *n,PetscInt *p)
39: PetscInt w;
40: DM_DA *dd = (DM_DA*)da->data;
44: /* since the xs, xe ... have all been multiplied by the number of degrees
45: of freedom per cell, w = dd->w, we divide that out before returning.*/
46: w = dd->w;
47: if (x) *x = dd->Xs/w + dd->xo;
48: if (y) *y = dd->Ys + dd->yo;
49: if (z) *z = dd->Zs + dd->zo;
50: if (m) *m = (dd->Xe - dd->Xs)/w;
51: if (n) *n = (dd->Ye - dd->Ys);
52: if (p) *p = (dd->Ze - dd->Zs);