Actual source code: ex1f.F
1: !
2: ! Description: Creates an index set based on a set of integers. Views that index set
3: ! and then destroys it.
4: !
5: !/*T
6: ! Concepts: index sets^manipulating a general index set;
7: !T*/
8: !
9: !
10: ! The following include statements are required for Fortran programs
11: ! that use PETSc index sets:
12: ! petsc.h - base PETSc routines
13: ! petscis.h - index sets (IS objects)
14: !
15: program main
16: implicit none
18: #include include/finclude/petsc.h
19: #include include/finclude/petscis.h
21: PetscErrorCode ierr
22: PetscInt indices(5),n,index1,index5
23: PetscMPIInt rank
24: PetscOffset ix
25: IS is
27: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
28: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
30: ! Create an index set with 5 entries. Each processor creates
31: ! its own index set with its own list of integers.
32:
33: indices(1) = rank + 1
34: indices(2) = rank + 2
35: indices(3) = rank + 3
36: indices(4) = rank + 4
37: indices(5) = rank + 5
39: ! if using 64bit integers cannot pass 5 into routine expecting an integer*8
40: n = 5
41: call ISCreateGeneral(PETSC_COMM_SELF,n,indices,is,ierr)
43: ! Print the index set to stdout
45: call ISView(is,PETSC_VIEWER_STDOUT_SELF,ierr)
47: ! Get the number of indices in the set
49: call ISGetLocalSize(is,n,ierr)
51: ! Get the indices in the index set
53: call ISGetIndices(is,indices,ix,ierr)
55: ! Now any code that needs access to the list of integers
56: ! has access to it here
58: !
59: ! Bug in IRIX64-F90 libraries - write/format cannot handle integer(integer*8 + integer)
60: !
62: index1 = indices(ix+1)
63: index5 = indices(ix+5)
64: write(6,100) rank,index1,index5
65: 100 format('[',i5,'] First index = ',i5,' fifth index = ',i5)
66:
67: ! Once we no longer need access to the indices they should
68: ! returned to the system
70: call ISRestoreIndices(is,indices,ix,ierr)
71:
72: ! All PETSc objects should be destroyed once they are
73: ! no longer needed
75: call ISDestroy(is,ierr)
76: call PetscFinalize(ierr)
77: end
79: