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arnoldi-distribuito/ex10.c

83 lines
2.9 KiB
C

#include <petscdm.h>
#include <petscdmda.h>
#include <petscsys.h>
#include <petscviewerhdf5.h>
static char help[] = "Test to write HDF5 file from PETSc DMDA Vec.\n\n";
int main(int argc, char **argv) {
DM da2D;
PetscInt i, j, ixs, ixm, iys, iym;
PetscViewer H5viewer;
PetscScalar xm = -1.0, xp = 1.0;
PetscScalar ym = -1.0, yp = 1.0;
PetscScalar value = 1.0, dx, dy;
PetscInt Nx = 40, Ny = 40;
Vec gauss, input;
PetscScalar **gauss_ptr;
PetscReal norm;
const char *vecname;
dx = (xp - xm) / (Nx - 1);
dy = (yp - ym) / (Ny - 1);
/* Initialize the Petsc context */
PetscFunctionBeginUser;
PetscCall(PetscInitialize(&argc, &argv, NULL, help));
PetscCall(DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE, DMDA_STENCIL_STAR, Nx, Ny,
PETSC_DECIDE, PETSC_DECIDE, 1, 1, NULL, NULL, &da2D));
PetscCall(DMSetFromOptions(da2D));
PetscCall(DMSetUp(da2D));
/* Set the coordinates */
PetscCall(DMDASetUniformCoordinates(da2D, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0));
/* Declare gauss as a DMDA component */
PetscCall(DMCreateGlobalVector(da2D, &gauss));
PetscCall(PetscObjectSetName((PetscObject)gauss, "pressure"));
/* Initialize vector gauss with a constant value (=1) */
PetscCall(VecSet(gauss, value));
/* Get the coordinates of the corners for each process */
PetscCall(DMDAGetCorners(da2D, &ixs, &iys, 0, &ixm, &iym, 0));
/* Build the gaussian profile (exp(-x^2-y^2)) */
PetscCall(DMDAVecGetArray(da2D, gauss, &gauss_ptr));
for (j = iys; j < iys + iym; j++) {
for (i = ixs; i < ixs + ixm; i++)
gauss_ptr[j][i] = PetscExpScalar(-(xm + i * dx) * (xm + i * dx) - (ym + j * dy) * (ym + j * dy));
}
PetscCall(DMDAVecRestoreArray(da2D, gauss, &gauss_ptr));
/* Create the HDF5 viewer */
PetscCall(PetscViewerHDF5Open(PETSC_COMM_WORLD, "gauss.h5", FILE_MODE_WRITE, &H5viewer));
PetscCall(PetscViewerSetFromOptions(H5viewer));
/* Write the H5 file */
PetscCall(VecView(gauss, H5viewer));
/* Close the viewer */
PetscCall(PetscViewerDestroy(&H5viewer));
PetscCall(VecDuplicate(gauss, &input));
PetscCall(PetscObjectGetName((PetscObject)gauss, &vecname));
PetscCall(PetscObjectSetName((PetscObject)input, vecname));
/* Create the HDF5 viewer for reading */
PetscCall(PetscViewerHDF5Open(PETSC_COMM_WORLD, "gauss.h5", FILE_MODE_READ, &H5viewer));
PetscCall(PetscViewerSetFromOptions(H5viewer));
PetscCall(VecLoad(input, H5viewer));
PetscCall(PetscViewerDestroy(&H5viewer));
PetscCall(VecAXPY(input, -1.0, gauss));
PetscCall(VecNorm(input, NORM_2, &norm));
PetscCheck(norm <= 1.e-6, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Vec read in does not match vector written out");
PetscCall(VecDestroy(&input));
PetscCall(VecDestroy(&gauss));
PetscCall(DMDestroy(&da2D));
PetscCall(PetscFinalize());
return 0;
}