Actual source code: ex157.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: int main(int argc, char **args)
5: {
6: PetscMPIInt rank, size;
7: PetscInt N0 = 2048, N1 = 2048, N2 = 3, N3 = 5, N4 = 5, N = N0 * N1;
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;
14: PetscScalar one = 1, two = 2, three = 3;
17: PetscInitialize(&argc, &args, (char *)0, help);
18: #if defined(PETSC_USE_COMPLEX)
19: SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "This example requires real numbers");
20: #endif
21: MPI_Comm_size(PETSC_COMM_WORLD, &size);
22: MPI_Comm_rank(PETSC_COMM_WORLD, &rank);
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: /* VecSet(input,one); */
30: /* VecSetValue(input,1,two,INSERT_VALUES); */
31: /* VecSetValue(input,2,three,INSERT_VALUES); */
32: /* VecSetValue(input,3,three,INSERT_VALUES); */
33: VecSetRandom(input, rdm);
34: /* VecSetRandom(input,rdm); */
35: /* VecSetRandom(input,rdm); */
36: VecDuplicate(input, &output);
38: DIM = 2;
39: dim[0] = N0;
40: dim[1] = N1;
41: dim[2] = N2;
42: dim[3] = N3;
43: dim[4] = N4;
44: MatCreateFFT(PETSC_COMM_WORLD, DIM, dim, MATFFTW, &A);
45: MatCreateVecsFFTW(A, &x, &y, &z);
46: /* MatCreateVecs(A,&x,&y); */
47: /* MatCreateVecs(A,&z,NULL); */
49: VecGetSize(x, &vsize);
50: printf("The vector size of input from the main routine is %d\n", vsize);
52: VecGetSize(z, &vsize);
53: printf("The vector size of output from the main routine is %d\n", vsize);
55: InputTransformFFT(A, input, x);
57: MatMult(A, x, y);
58: VecAssemblyBegin(y);
59: VecAssemblyEnd(y);
60: VecView(y, PETSC_VIEWER_STDOUT_WORLD);
62: MatMultTranspose(A, y, z);
64: OutputTransformFFT(A, z, output);
65: fac = 1.0 / (PetscReal)N;
66: VecScale(output, fac);
68: VecAssemblyBegin(input);
69: VecAssemblyEnd(input);
70: VecAssemblyBegin(output);
71: VecAssemblyEnd(output);
73: /* VecView(input,PETSC_VIEWER_STDOUT_WORLD); */
74: /* VecView(output,PETSC_VIEWER_STDOUT_WORLD); */
76: VecAXPY(output, -1.0, input);
77: VecNorm(output, NORM_1, &enorm);
78: /* if (enorm > 1.e-14) { */
79: PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm);
80: /* } */
82: VecDestroy(&output);
83: VecDestroy(&input);
84: VecDestroy(&x);
85: VecDestroy(&y);
86: VecDestroy(&z);
87: MatDestroy(&A);
88: PetscRandomDestroy(&rdm);
89: PetscFinalize();
90: return 0;
91: }