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;
16: PetscInitialize(&argc,&args,(char*)0,help);
17: #if defined(PETSC_USE_COMPLEX)
18: SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers");
19: #endif
20: MPI_Comm_size(PETSC_COMM_WORLD, &size);
21: MPI_Comm_rank(PETSC_COMM_WORLD, &rank);
23: PetscRandomCreate(PETSC_COMM_WORLD, &rdm);
24: PetscRandomSetFromOptions(rdm);
25: VecCreate(PETSC_COMM_WORLD,&input);
26: VecSetSizes(input,PETSC_DECIDE,N);
27: VecSetFromOptions(input);
28: /* VecSet(input,one); */
29: /* VecSetValue(input,1,two,INSERT_VALUES); */
30: /* VecSetValue(input,2,three,INSERT_VALUES); */
31: /* VecSetValue(input,3,three,INSERT_VALUES); */
32: VecSetRandom(input,rdm);
33: /* VecSetRandom(input,rdm); */
34: /* VecSetRandom(input,rdm); */
35: VecDuplicate(input,&output);
37: DIM = 2; dim[0] = N0; dim[1] = N1; dim[2] = N2; dim[3] = N3; dim[4] = N4;
38: MatCreateFFT(PETSC_COMM_WORLD,DIM,dim,MATFFTW,&A);
39: MatCreateVecsFFTW(A,&x,&y,&z);
40: /* MatCreateVecs(A,&x,&y); */
41: /* MatCreateVecs(A,&z,NULL); */
43: VecGetSize(x,&vsize);
44: printf("The vector size of input from the main routine is %d\n",vsize);
46: VecGetSize(z,&vsize);
47: printf("The vector size of output from the main routine is %d\n",vsize);
49: InputTransformFFT(A,input,x);
51: MatMult(A,x,y);
52: VecAssemblyBegin(y);
53: VecAssemblyEnd(y);
54: VecView(y,PETSC_VIEWER_STDOUT_WORLD);
56: MatMultTranspose(A,y,z);
58: OutputTransformFFT(A,z,output);
59: fac = 1.0/(PetscReal)N;
60: VecScale(output,fac);
62: VecAssemblyBegin(input);
63: VecAssemblyEnd(input);
64: VecAssemblyBegin(output);
65: VecAssemblyEnd(output);
67: /* VecView(input,PETSC_VIEWER_STDOUT_WORLD); */
68: /* VecView(output,PETSC_VIEWER_STDOUT_WORLD); */
70: VecAXPY(output,-1.0,input);
71: VecNorm(output,NORM_1,&enorm);
72: /* if (enorm > 1.e-14) { */
73: PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm);
74: /* } */
76: VecDestroy(&output);
77: VecDestroy(&input);
78: VecDestroy(&x);
79: VecDestroy(&y);
80: VecDestroy(&z);
81: MatDestroy(&A);
82: PetscRandomDestroy(&rdm);
83: PetscFinalize();
84: return 0;
86: }