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