Actual source code: ex150.c
1: static char help[] = "This program illustrates the use of PETSc-fftw interface for real DFT\n";
2: #include <petscmat.h>
3: #include <fftw3-mpi.h>
5: extern PetscErrorCode InputTransformFFT(Mat, Vec, Vec);
6: extern PetscErrorCode OutputTransformFFT(Mat, Vec, Vec);
7: int main(int argc, char **args)
8: {
9: PetscMPIInt rank, size;
10: PetscInt N0 = 3, N1 = 3, N2 = 3, N3 = 3, N4 = 3, N = N0 * N1 * N2 * N3;
11: PetscRandom rdm;
12: PetscReal enorm;
13: Vec x, y, z, input, output;
14: Mat A;
15: PetscInt DIM, dim[5], vsize;
16: PetscReal fac;
17: PetscScalar one = 1;
20: PetscInitialize(&argc, &args, (char *)0, help);
21: #if defined(PETSC_USE_COMPLEX)
22: SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "This example requires real numbers");
23: #endif
25: MPI_Comm_size(PETSC_COMM_WORLD, &size);
26: MPI_Comm_rank(PETSC_COMM_WORLD, &rank);
28: PetscRandomCreate(PETSC_COMM_WORLD, &rdm);
29: PetscRandomSetFromOptions(rdm);
30: VecCreate(PETSC_COMM_WORLD, &input);
31: VecSetSizes(input, PETSC_DECIDE, N);
32: VecSetFromOptions(input);
33: VecSetRandom(input, rdm);
34: VecAssemblyBegin(input);
35: VecAssemblyEnd(input);
36: /* VecView(input,PETSC_VIEWER_STDOUT_WORLD); */
37: VecDuplicate(input, &output);
39: DIM = 4;
40: dim[0] = N0;
41: dim[1] = N1;
42: dim[2] = N2;
43: dim[3] = N3;
44: dim[4] = N4;
46: MatCreateFFT(PETSC_COMM_WORLD, DIM, dim, MATFFTW, &A);
47: MatCreateVecs(A, &x, &y);
48: MatCreateVecs(A, &z, NULL);
49: VecGetSize(x, &vsize);
50: printf("The vector size from the main routine is %d\n", vsize);
52: InputTransformFFT(A, input, x);
54: MatMult(A, x, y);
55: VecAssemblyBegin(y);
56: VecAssemblyEnd(y);
57: VecView(y, PETSC_VIEWER_STDOUT_WORLD);
58: MatMultTranspose(A, y, z);
59: VecGetSize(z, &vsize);
60: printf("The vector size of zfrom the main routine is %d\n", vsize);
62: OutputTransformFFT(A, z, output);
64: fac = 1.0 / (PetscReal)N;
65: VecScale(output, fac);
67: VecAssemblyBegin(input);
68: VecAssemblyEnd(input);
69: VecAssemblyBegin(output);
70: VecAssemblyEnd(output);
72: VecView(input, PETSC_VIEWER_STDOUT_WORLD);
73: VecView(output, PETSC_VIEWER_STDOUT_WORLD);
75: VecAXPY(output, -1.0, input);
76: VecNorm(output, NORM_1, &enorm);
77: /* if (enorm > 1.e-14) { */
78: if (rank == 0) PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm);
79: /* } */
81: /* MatCreateVecs(A,&z,NULL); */
82: /* printf("Vector size from ex148 %d\n",vsize); */
83: /* PetscObjectSetName((PetscObject) x, "Real space vector"); */
84: /* PetscObjectSetName((PetscObject) y, "Frequency space vector"); */
85: /* PetscObjectSetName((PetscObject) z, "Reconstructed vector"); */
87: VecDestroy(&output);
88: VecDestroy(&input);
89: VecDestroy(&x);
90: VecDestroy(&y);
91: VecDestroy(&z);
92: MatDestroy(&A);
93: PetscRandomDestroy(&rdm);
94: PetscFinalize();
95: return 0;
96: }