1 2 /* 3 Code for manipulating distributed regular arrays in parallel. 4 */ 5 6 #include <petsc/private/dmdaimpl.h> /*I "petscdmda.h" I*/ 7 8 #undef __FUNCT__ 9 #define __FUNCT__ "DMDAGetGhostCorners" 10 /*@ 11 DMDAGetGhostCorners - Returns the global (x,y,z) indices of the lower left 12 corner and size of the local region, including ghost points. 13 14 Not Collective 15 16 Input Parameter: 17 . da - the distributed array 18 19 Output Parameters: 20 + x,y,z - the corner indices (where y and z are optional; these are used 21 for 2D and 3D problems) 22 - m,n,p - widths in the corresponding directions (where n and p are optional; 23 these are used for 2D and 3D problems) 24 25 Level: beginner 26 27 Note: 28 The corner information is independent of the number of degrees of 29 freedom per node set with the DMDACreateXX() routine. Thus the x, y, z, and 30 m, n, p can be thought of as coordinates on a logical grid, where each 31 grid point has (potentially) several degrees of freedom. 32 Any of y, z, n, and p can be passed in as NULL if not needed. 33 34 .keywords: distributed array, get, ghost, corners, nodes, local indices 35 36 .seealso: DMDAGetCorners(), DMDACreate1d(), DMDACreate2d(), DMDACreate3d(), DMDAGetOwnershipRanges() 37 38 @*/ 39 PetscErrorCode DMDAGetGhostCorners(DM da,PetscInt *x,PetscInt *y,PetscInt *z,PetscInt *m,PetscInt *n,PetscInt *p) 40 { 41 PetscInt w; 42 DM_DA *dd = (DM_DA*)da->data; 43 44 PetscFunctionBegin; 45 PetscValidHeaderSpecific(da,DM_CLASSID,1); 46 /* since the xs, xe ... have all been multiplied by the number of degrees 47 of freedom per cell, w = dd->w, we divide that out before returning.*/ 48 w = dd->w; 49 if (x) *x = dd->Xs/w + dd->xo; 50 if (y) *y = dd->Ys + dd->yo; 51 if (z) *z = dd->Zs + dd->zo; 52 if (m) *m = (dd->Xe - dd->Xs)/w; 53 if (n) *n = (dd->Ye - dd->Ys); 54 if (p) *p = (dd->Ze - dd->Zs); 55 PetscFunctionReturn(0); 56 } 57 58