Actual source code: ex150.c
petsc-3.3-p6 2013-02-11
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>
7: extern PetscErrorCode InputTransformFFT(Mat,Vec,Vec);
8: extern PetscErrorCode OutputTransformFFT(Mat,Vec,Vec);
9: PetscInt main(PetscInt argc,char **args)
10: {
11: PetscErrorCode ierr;
12: PetscMPIInt rank,size;
13: PetscInt N0=3,N1=3,N2=3,N3=3,N4=3,N=N0*N1*N2*N3;
14: PetscRandom rdm;
15: PetscReal enorm;
16: Vec x,y,z,input,output;
17: Mat A;
18: PetscInt DIM, dim[5],vsize;
19: PetscReal fac;
20: PetscScalar one=1;
22: PetscInitialize(&argc,&args,(char *)0,help);
23: #if defined(PETSC_USE_COMPLEX)
24: SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers");
25: #endif
27: MPI_Comm_size(PETSC_COMM_WORLD, &size);
28: MPI_Comm_rank(PETSC_COMM_WORLD, &rank);
30: PetscRandomCreate(PETSC_COMM_WORLD, &rdm);
31: PetscRandomSetFromOptions(rdm);
32: VecCreate(PETSC_COMM_WORLD,&input);
33: VecSetSizes(input,PETSC_DECIDE,N);
34: VecSetFromOptions(input);
35: VecSetRandom(input,rdm);
36: VecAssemblyBegin(input);
37: VecAssemblyEnd(input);
38: // VecView(input,PETSC_VIEWER_STDOUT_WORLD);
39: VecDuplicate(input,&output);
41: DIM = 4;
42: dim[0] = N0; dim[1] = N1; dim[2] = N2; dim[3] = N3; dim[4] = N4;
44: MatCreateFFT(PETSC_COMM_WORLD,DIM,dim,MATFFTW,&A);
45: MatGetVecs(A,&x,&y);
46: MatGetVecs(A,&z,PETSC_NULL);
47: VecGetSize(x,&vsize);
48: printf("The vector size from the main routine is %d\n",vsize);
50: InputTransformFFT(A,input,x);
52: MatMult(A,x,y);
53: VecAssemblyBegin(y);
54: VecAssemblyEnd(y);
55: VecView(y,PETSC_VIEWER_STDOUT_WORLD);
56: MatMultTranspose(A,y,z);
57: VecGetSize(z,&vsize);
58: printf("The vector size of zfrom the main routine is %d\n",vsize);
60: OutputTransformFFT(A,z,output);
62: fac = 1.0/(PetscReal)N;
63: VecScale(output,fac);
65: VecAssemblyBegin(input);
66: VecAssemblyEnd(input);
67: VecAssemblyBegin(output);
68: VecAssemblyEnd(output);
70: VecView(input,PETSC_VIEWER_STDOUT_WORLD);
71: VecView(output,PETSC_VIEWER_STDOUT_WORLD);
73: VecAXPY(output,-1.0,input);
74: VecNorm(output,NORM_1,&enorm);
75: // if (enorm > 1.e-14){
76: if (!rank)
77: PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm);
78: // }
81:
82:
83: // MatGetVecs(A,&z,PETSC_NULL);
84: // printf("Vector size from ex148 %d\n",vsize);
85: // PetscObjectSetName((PetscObject) x, "Real space vector");
86: // PetscObjectSetName((PetscObject) y, "Frequency space vector");
87: // PetscObjectSetName((PetscObject) z, "Reconstructed vector");
89: VecDestroy(&output);
90: VecDestroy(&input);
91: VecDestroy(&x);
92: VecDestroy(&y);
93: VecDestroy(&z);
94: MatDestroy(&A);
95: PetscRandomDestroy(&rdm);
96: PetscFinalize();
97: return 0;
98: }