Actual source code: ex155.c
1: static char help[] = "This program illustrates the use of PETSc-fftw interface for parallel real DFT\n";
2: #include <petscmat.h>
3: #include <fftw3-mpi.h>
4: /*extern PetscErrorCode MatCreateVecsFFT(Mat,Vec *,Vec *,Vec *);*/
5: int main(int argc, char **args)
6: {
7: PetscMPIInt rank, size;
8: PetscInt N0 = 4096, N1 = 4096, N2 = 256, N3 = 10, N4 = 10, N = N0 * N1;
9: PetscRandom rdm;
10: PetscReal enorm;
11: Vec x, y, z, input, output;
12: Mat A;
13: PetscInt DIM, dim[5], vsize, row, col;
14: PetscReal fac;
17: PetscInitialize(&argc, &args, (char *)0, help);
18: MPI_Comm_size(PETSC_COMM_WORLD, &size);
19: MPI_Comm_rank(PETSC_COMM_WORLD, &rank);
21: #if defined(PETSC_USE_COMPLEX)
22: SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "Example for Real DFT. Your current data type is complex!");
23: #endif
24: PetscRandomCreate(PETSC_COMM_WORLD, &rdm);
25: PetscRandomSetFromOptions(rdm);
26: VecCreate(PETSC_COMM_WORLD, &input);
27: VecSetSizes(input, PETSC_DECIDE, N);
28: VecSetFromOptions(input);
29: VecSetRandom(input, rdm);
30: VecDuplicate(input, &output);
32: DIM = 2;
33: dim[0] = N0;
34: dim[1] = N1;
35: dim[2] = N2;
36: dim[3] = N3;
37: dim[4] = N4;
38: MatCreateFFT(PETSC_COMM_WORLD, DIM, dim, MATFFTW, &A);
39: MatGetLocalSize(A, &row, &col);
40: printf("The Matrix size is %d and %d from process %d\n", row, col, rank);
41: MatCreateVecsFFTW(A, &x, &y, &z);
43: VecGetSize(x, &vsize);
45: VecGetSize(z, &vsize);
46: printf("The vector size of output from the main routine is %d\n", vsize);
48: VecScatterPetscToFFTW(A, input, x);
49: /*VecDestroy(&input);*/
50: MatMult(A, x, y);
51: MatMultTranspose(A, y, z);
52: VecScatterFFTWToPetsc(A, z, output);
53: /*VecDestroy(&z);*/
54: fac = 1.0 / (PetscReal)N;
55: VecScale(output, fac);
57: VecAssemblyBegin(input);
58: VecAssemblyEnd(input);
59: VecAssemblyBegin(output);
60: VecAssemblyEnd(output);
62: /* VecView(input,PETSC_VIEWER_STDOUT_WORLD);*/
63: /* VecView(output,PETSC_VIEWER_STDOUT_WORLD);*/
65: VecAXPY(output, -1.0, input);
66: VecNorm(output, NORM_1, &enorm);
67: if (enorm > 1.e-14) PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm);
69: VecDestroy(&x);
70: VecDestroy(&y);
71: VecDestroy(&z);
72: VecDestroy(&output);
73: VecDestroy(&input);
74: MatDestroy(&A);
75: PetscRandomDestroy(&rdm);
76: PetscFinalize();
77: return 0;
78: }