Actual source code: ex3.c
2: /* "$Id: ex3.c,v 1.21 2001/03/23 23:21:14 balay Exp $"; */
4: static char help[] = "Demonstrates creating a blocked index set.nn";
6: /*T
7: Concepts: index sets^creating a block index set;
8: Concepts: IS^creating a block index set;
10: Description: Creates an index set based on blocks of integers. Views that index set
11: and then destroys it.
12: T*/
14: #include petscis.h
16: int main(int argc,char **argv)
17: {
18: int i,n = 4,ierr, inputindices[] = {0,3,9,12},bs = 3,issize,*indices;
19: IS set;
20: PetscTruth isblock;
22: PetscInitialize(&argc,&argv,(char*)0,help);
23:
24: /*
25: Create a block index set. The index set has 4 blocks each of size 3.
26: The indices are {0,1,2,3,4,5,9,10,11,12,13,14}
27: Note each processor is generating its own index set
28: (in this case they are all identical)
29: */
30: ISCreateBlock(PETSC_COMM_SELF,bs,n,inputindices,&set);
31: ISView(set,PETSC_VIEWER_STDOUT_SELF);
33: /*
34: Extract indices from set.
35: */
36: ISGetLocalSize(set,&issize);
37: ISGetIndices(set,&indices);
38: PetscPrintf(PETSC_COMM_SELF,"Printing indices directlyn");
39: for (i=0; i<issize; i++) {
40: PetscPrintf(PETSC_COMM_SELF,"%dn",indices[i]);
41: }
42: ISRestoreIndices(set,&indices);
44: /*
45: Extract the block indices. This returns one index per block.
46: */
47: ISBlockGetIndices(set,&indices);
48: PetscPrintf(PETSC_COMM_SELF,"Printing block indices directlyn");
49: for (i=0; i<n; i++) {
50: PetscPrintf(PETSC_COMM_SELF,"%dn",indices[i]);
51: }
52: ISBlockRestoreIndices(set,&indices);
54: /*
55: Check if this is really a block index set
56: */
57: ISBlock(set,&isblock);
58: if (isblock != PETSC_TRUE) SETERRQ(1,"Index set is not blocked!");
60: /*
61: Determine the block size of the index set
62: */
63: ISBlockGetBlockSize(set,&bs);
64: if (bs != 3) SETERRQ(1,"Block size is not 3!");
66: /*
67: Get the number of blocks
68: */
69: ISBlockGetSize(set,&n);
70: if (n != 4) SETERRQ(1,"Number of blocks not 4!");
72: ISDestroy(set);
73: PetscFinalize();
74: return 0;
75: }