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