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> 4 5 extern PetscErrorCode InputTransformFFT(Mat,Vec,Vec); 6 extern PetscErrorCode OutputTransformFFT(Mat,Vec,Vec); 7 int main(int argc,char **args) 8 { 9 PetscErrorCode ierr; 10 PetscMPIInt rank,size; 11 PetscInt N0=3,N1=3,N2=3,N3=3,N4=3,N=N0*N1*N2*N3; 12 PetscRandom rdm; 13 PetscReal enorm; 14 Vec x,y,z,input,output; 15 Mat A; 16 PetscInt DIM, dim[5],vsize; 17 PetscReal fac; 18 PetscScalar one=1; 19 20 ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr; 21 #if defined(PETSC_USE_COMPLEX) 22 SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers"); 23 #endif 24 25 CHKERRMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 26 CHKERRMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 27 28 CHKERRQ(PetscRandomCreate(PETSC_COMM_WORLD, &rdm)); 29 CHKERRQ(PetscRandomSetFromOptions(rdm)); 30 CHKERRQ(VecCreate(PETSC_COMM_WORLD,&input)); 31 CHKERRQ(VecSetSizes(input,PETSC_DECIDE,N)); 32 CHKERRQ(VecSetFromOptions(input)); 33 CHKERRQ(VecSetRandom(input,rdm)); 34 CHKERRQ(VecAssemblyBegin(input)); 35 CHKERRQ(VecAssemblyEnd(input)); 36 /* CHKERRQ(VecView(input,PETSC_VIEWER_STDOUT_WORLD)); */ 37 CHKERRQ(VecDuplicate(input,&output)); 38 39 DIM = 4; 40 dim[0] = N0; dim[1] = N1; dim[2] = N2; dim[3] = N3; dim[4] = N4; 41 42 CHKERRQ(MatCreateFFT(PETSC_COMM_WORLD,DIM,dim,MATFFTW,&A)); 43 CHKERRQ(MatCreateVecs(A,&x,&y)); 44 CHKERRQ(MatCreateVecs(A,&z,NULL)); 45 CHKERRQ(VecGetSize(x,&vsize)); 46 printf("The vector size from the main routine is %d\n",vsize); 47 48 CHKERRQ(InputTransformFFT(A,input,x)); 49 50 CHKERRQ(MatMult(A,x,y)); 51 CHKERRQ(VecAssemblyBegin(y)); 52 CHKERRQ(VecAssemblyEnd(y)); 53 CHKERRQ(VecView(y,PETSC_VIEWER_STDOUT_WORLD)); 54 CHKERRQ(MatMultTranspose(A,y,z)); 55 CHKERRQ(VecGetSize(z,&vsize)); 56 printf("The vector size of zfrom the main routine is %d\n",vsize); 57 58 CHKERRQ(OutputTransformFFT(A,z,output)); 59 60 fac = 1.0/(PetscReal)N; 61 CHKERRQ(VecScale(output,fac)); 62 63 CHKERRQ(VecAssemblyBegin(input)); 64 CHKERRQ(VecAssemblyEnd(input)); 65 CHKERRQ(VecAssemblyBegin(output)); 66 CHKERRQ(VecAssemblyEnd(output)); 67 68 CHKERRQ(VecView(input,PETSC_VIEWER_STDOUT_WORLD)); 69 CHKERRQ(VecView(output,PETSC_VIEWER_STDOUT_WORLD)); 70 71 CHKERRQ(VecAXPY(output,-1.0,input)); 72 CHKERRQ(VecNorm(output,NORM_1,&enorm)); 73 /* if (enorm > 1.e-14) { */ 74 if (rank == 0) { 75 CHKERRQ(PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm)); 76 } 77 /* } */ 78 79 /* CHKERRQ(MatCreateVecs(A,&z,NULL)); */ 80 /* printf("Vector size from ex148 %d\n",vsize); */ 81 /* CHKERRQ(PetscObjectSetName((PetscObject) x, "Real space vector")); */ 82 /* CHKERRQ(PetscObjectSetName((PetscObject) y, "Frequency space vector")); */ 83 /* CHKERRQ(PetscObjectSetName((PetscObject) z, "Reconstructed vector")); */ 84 85 CHKERRQ(VecDestroy(&output)); 86 CHKERRQ(VecDestroy(&input)); 87 CHKERRQ(VecDestroy(&x)); 88 CHKERRQ(VecDestroy(&y)); 89 CHKERRQ(VecDestroy(&z)); 90 CHKERRQ(MatDestroy(&A)); 91 CHKERRQ(PetscRandomDestroy(&rdm)); 92 ierr = PetscFinalize(); 93 return ierr; 94 } 95