Actual source code: ex10.c
1: /*
2: Demonstrates using the HDF5 viewer with a DMDA Vec
3: - create a global vector containing a gauss profile (exp(-x^2-y^2))
4: - write the global vector in a hdf5 file
6: The resulting file gauss.h5 can be viewed with Visit (an open source visualization package)
7: Or with some versions of MATLAB with data=hdfread('gauss.h5','pressure'); mesh(data);
9: The file storage of the vector is independent of the number of processes used.
10: */
12: #include <petscdm.h>
13: #include <petscdmda.h>
14: #include <petscsys.h>
15: #include <petscviewerhdf5.h>
17: static char help[] = "Test to write HDF5 file from PETSc DMDA Vec.\n\n";
19: int main(int argc,char **argv)
20: {
21: DM da2D;
22: PetscInt i,j,ixs, ixm, iys, iym;
23: PetscViewer H5viewer;
24: PetscScalar xm = -1.0, xp=1.0;
25: PetscScalar ym = -1.0, yp=1.0;
26: PetscScalar value = 1.0,dx,dy;
27: PetscInt Nx = 40, Ny=40;
28: Vec gauss,input;
29: PetscScalar **gauss_ptr;
30: PetscReal norm;
31: const char *vecname;
33: dx=(xp-xm)/(Nx-1);
34: dy=(yp-ym)/(Ny-1);
36: /* Initialize the Petsc context */
37: PetscInitialize(&argc,&argv,(char*)0,help);
38: DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,Nx,Ny,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,&da2D);
39: DMSetFromOptions(da2D);
40: DMSetUp(da2D);
42: /* Set the coordinates */
43: DMDASetUniformCoordinates(da2D, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0);
45: /* Declare gauss as a DMDA component */
46: DMCreateGlobalVector(da2D,&gauss);
47: PetscObjectSetName((PetscObject) gauss, "pressure");
49: /* Initialize vector gauss with a constant value (=1) */
50: VecSet(gauss,value);
52: /* Get the coordinates of the corners for each process */
53: DMDAGetCorners(da2D, &ixs, &iys, 0, &ixm, &iym, 0);
55: /* Build the gaussian profile (exp(-x^2-y^2)) */
56: DMDAVecGetArray(da2D,gauss,&gauss_ptr);
57: for (j=iys; j<iys+iym; j++) {
58: for (i=ixs; i<ixs+ixm; i++) {
59: gauss_ptr[j][i]=PetscExpScalar(-(xm+i*dx)*(xm+i*dx)-(ym+j*dy)*(ym+j*dy));
60: }
61: }
62: DMDAVecRestoreArray(da2D,gauss,&gauss_ptr);
64: /* Create the HDF5 viewer */
65: PetscViewerHDF5Open(PETSC_COMM_WORLD,"gauss.h5",FILE_MODE_WRITE,&H5viewer);
66: PetscViewerSetFromOptions(H5viewer);
68: /* Write the H5 file */
69: VecView(gauss,H5viewer);
71: /* Close the viewer */
72: PetscViewerDestroy(&H5viewer);
74: VecDuplicate(gauss,&input);
75: PetscObjectGetName((PetscObject)gauss,&vecname);
76: PetscObjectSetName((PetscObject)input,vecname);
78: /* Create the HDF5 viewer for reading */
79: PetscViewerHDF5Open(PETSC_COMM_WORLD,"gauss.h5",FILE_MODE_READ,&H5viewer);
80: PetscViewerSetFromOptions(H5viewer);
81: VecLoad(input,H5viewer);
82: PetscViewerDestroy(&H5viewer);
84: VecAXPY(input,-1.0,gauss);
85: VecNorm(input,NORM_2,&norm);
88: VecDestroy(&input);
89: VecDestroy(&gauss);
90: DMDestroy(&da2D);
91: PetscFinalize();
92: return 0;
93: }
95: /*TEST
97: build:
98: requires: hdf5 !defined(PETSC_USE_CXXCOMPLEX)
100: test:
101: nsize: 4
103: test:
104: nsize: 4
105: suffix: 2
106: args: -viewer_hdf5_base_dimension2
107: output_file: output/ex10_1.out
109: test:
110: nsize: 4
111: suffix: 3
112: args: -viewer_hdf5_sp_output
113: output_file: output/ex10_1.out
115: TEST*/