Actual source code: ex153.c
1: static char help[] = "This program illustrates the use of PETSc-fftw interface for sequential real DFT\n";
2: #include <petscmat.h>
3: #include <fftw3-mpi.h>
4: int main(int argc, char **args)
5: {
6: PetscMPIInt rank, size;
7: PetscInt N0 = 10, N1 = 10, N2 = 10, N3 = 10, N4 = 10, N = N0 * N1 * N2 * N3 * N4;
8: PetscRandom rdm;
9: PetscReal enorm;
10: Vec x, y, z, input, output;
11: Mat A;
12: PetscInt DIM, dim[5], vsize;
13: PetscReal fac;
15: PetscFunctionBeginUser;
16: PetscCall(PetscInitialize(&argc, &args, NULL, help));
17: #if defined(PETSC_USE_COMPLEX)
18: SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "This example requires real numbers");
19: #endif
20: PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
21: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
23: PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "This is a uni-processor example only");
24: PetscCall(PetscRandomCreate(PETSC_COMM_SELF, &rdm));
25: PetscCall(PetscRandomSetFromOptions(rdm));
26: PetscCall(VecCreate(PETSC_COMM_SELF, &input));
27: PetscCall(VecSetSizes(input, N, N));
28: PetscCall(VecSetFromOptions(input));
29: PetscCall(VecSetRandom(input, rdm));
30: PetscCall(VecDuplicate(input, &output));
32: DIM = 5;
33: dim[0] = N0;
34: dim[1] = N1;
35: dim[2] = N2;
36: dim[3] = N3;
37: dim[4] = N4;
38: PetscCall(MatCreateFFT(PETSC_COMM_SELF, DIM, dim, MATFFTW, &A));
39: PetscCall(MatCreateVecs(A, &x, &y));
40: PetscCall(MatCreateVecs(A, &z, NULL));
42: PetscCall(VecGetSize(x, &vsize));
43: printf("The vector size of input from the main routine is %d\n", vsize);
45: PetscCall(VecGetSize(z, &vsize));
46: printf("The vector size of output from the main routine is %d\n", vsize);
48: PetscCall(InputTransformFFT(A, input, x));
50: PetscCall(MatMult(A, x, y));
51: PetscCall(MatMultTranspose(A, y, z));
53: PetscCall(OutputTransformFFT(A, z, output));
54: fac = 1.0 / (PetscReal)N;
55: PetscCall(VecScale(output, fac));
56: /*
57: PetscCall(VecAssemblyBegin(input));
58: PetscCall(VecAssemblyEnd(input));
59: PetscCall(VecAssemblyBegin(output));
60: PetscCall(VecAssemblyEnd(output));
62: PetscCall(VecView(input,PETSC_VIEWER_STDOUT_WORLD));
63: PetscCall(VecView(output,PETSC_VIEWER_STDOUT_WORLD));
64: */
65: PetscCall(VecAXPY(output, -1.0, input));
66: PetscCall(VecNorm(output, NORM_1, &enorm));
67: /* if (enorm > 1.e-14) { */
68: PetscCall(PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm));
69: /* } */
71: PetscCall(VecDestroy(&output));
72: PetscCall(VecDestroy(&input));
73: PetscCall(VecDestroy(&x));
74: PetscCall(VecDestroy(&y));
75: PetscCall(VecDestroy(&z));
76: PetscCall(MatDestroy(&A));
77: PetscCall(PetscRandomDestroy(&rdm));
78: PetscCall(PetscFinalize());
79: return 0;
80: }