Actual source code: ex1.c
1: /*$Id: ex1.c,v 1.28 2001/04/10 19:35:58 bsmith Exp $*/
3: static char help[] = "Reads a PETSc matrix and vector from a file and reorders it.n
4: -f0 <input_file> : first file to load (small system)n
5: -f1 <input_file> : second file to load (larger system)nn";
7: /*T
8: Concepts: Mat^ordering a matrix - loading a binary matrix and vector;
9: Concepts: Mat^loading a binary matrix and vector;
10: Concepts: Vectors^loading a binary vector;
11: Concepts: PetscLog^preloading executable
12: Processors: 1
13: T*/
15: /*
16: Include "petscmat.h" so that we can use matrices.
17: automatically includes:
18: petsc.h - base PETSc routines petscvec.h - vectors
19: petscsys.h - system routines petscmat.h - matrices
20: petscis.h - index sets petscviewer.h - viewers
21: */
22: #include petscmat.h
24: int main(int argc,char **args)
25: {
26: Mat A; /* matrix */
27: PetscViewer fd; /* viewer */
28: char file[2][128]; /* input file name */
29: IS isrow,iscol; /* row and column permutations */
30: int ierr;
31: MatOrderingType rtype = MATORDERING_RCM;
32: PetscTruth flg,PreLoad = PETSC_FALSE;
34: PetscInitialize(&argc,&args,(char *)0,help);
37: /*
38: Determine files from which we read the two linear systems
39: (matrix and right-hand-side vector).
40: */
41: PetscOptionsGetString(PETSC_NULL,"-f0",file[0],127,&flg);
42: if (!flg) SETERRQ(1,"Must indicate binary file with the -f0 option");
43: PetscOptionsGetString(PETSC_NULL,"-f1",file[1],127,&flg);
44: if (flg) PreLoad = PETSC_TRUE;
46: /* -----------------------------------------------------------
47: Beginning of loop
48: ----------------------------------------------------------- */
49: /*
50: Loop through the reordering 2 times.
51: - The intention here is to preload and solve a small system;
52: then load another (larger) system and solve it as well.
53: This process preloads the instructions with the smaller
54: system so that more accurate performance monitoring (via
55: -log_summary) can be done with the larger one (that actually
56: is the system of interest).
57: */
58: PreLoadBegin(PreLoad,"Load");
60: /* - - - - - - - - - - - New Stage - - - - - - - - - - - - -
61: Load system i
62: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
64: /*
65: Open binary file. Note that we use PETSC_BINARY_RDONLY to indicate
66: reading from this file.
67: */
68: PetscViewerBinaryOpen(PETSC_COMM_WORLD,file[PreLoadIt],PETSC_BINARY_RDONLY,&fd);
70: /*
71: Load the matrix; then destroy the viewer.
72: */
73: MatLoad(fd,MATSEQAIJ,&A);
74: PetscViewerDestroy(fd);
77: /* - - - - - - - - - - - New Stage - - - - - - - - - - - - -
78: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
80: PreLoadStage("Reordering");
81: MatGetOrdering(A,rtype,&isrow,&iscol);
83: /*
84: Free work space. All PETSc objects should be destroyed when they
85: are no longer needed.
86: */
87: MatDestroy(A);
88: ISDestroy(isrow);
89: ISDestroy(iscol);
90: PreLoadEnd();
92: PetscFinalize();
93: return 0;
94: }