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 PetscFunctionBeginUser; 20 PetscCall(PetscInitialize(&argc,&args,(char*)0,help)); 21 #if defined(PETSC_USE_COMPLEX) 22 SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers"); 23 #endif 24 25 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 26 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 27 28 PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &rdm)); 29 PetscCall(PetscRandomSetFromOptions(rdm)); 30 PetscCall(VecCreate(PETSC_COMM_WORLD,&input)); 31 PetscCall(VecSetSizes(input,PETSC_DECIDE,N)); 32 PetscCall(VecSetFromOptions(input)); 33 PetscCall(VecSetRandom(input,rdm)); 34 PetscCall(VecAssemblyBegin(input)); 35 PetscCall(VecAssemblyEnd(input)); 36 /* PetscCall(VecView(input,PETSC_VIEWER_STDOUT_WORLD)); */ 37 PetscCall(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 PetscCall(MatCreateFFT(PETSC_COMM_WORLD,DIM,dim,MATFFTW,&A)); 43 PetscCall(MatCreateVecs(A,&x,&y)); 44 PetscCall(MatCreateVecs(A,&z,NULL)); 45 PetscCall(VecGetSize(x,&vsize)); 46 printf("The vector size from the main routine is %d\n",vsize); 47 48 PetscCall(InputTransformFFT(A,input,x)); 49 50 PetscCall(MatMult(A,x,y)); 51 PetscCall(VecAssemblyBegin(y)); 52 PetscCall(VecAssemblyEnd(y)); 53 PetscCall(VecView(y,PETSC_VIEWER_STDOUT_WORLD)); 54 PetscCall(MatMultTranspose(A,y,z)); 55 PetscCall(VecGetSize(z,&vsize)); 56 printf("The vector size of zfrom the main routine is %d\n",vsize); 57 58 PetscCall(OutputTransformFFT(A,z,output)); 59 60 fac = 1.0/(PetscReal)N; 61 PetscCall(VecScale(output,fac)); 62 63 PetscCall(VecAssemblyBegin(input)); 64 PetscCall(VecAssemblyEnd(input)); 65 PetscCall(VecAssemblyBegin(output)); 66 PetscCall(VecAssemblyEnd(output)); 67 68 PetscCall(VecView(input,PETSC_VIEWER_STDOUT_WORLD)); 69 PetscCall(VecView(output,PETSC_VIEWER_STDOUT_WORLD)); 70 71 PetscCall(VecAXPY(output,-1.0,input)); 72 PetscCall(VecNorm(output,NORM_1,&enorm)); 73 /* if (enorm > 1.e-14) { */ 74 if (rank == 0) { 75 PetscCall(PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm)); 76 } 77 /* } */ 78 79 /* PetscCall(MatCreateVecs(A,&z,NULL)); */ 80 /* printf("Vector size from ex148 %d\n",vsize); */ 81 /* PetscCall(PetscObjectSetName((PetscObject) x, "Real space vector")); */ 82 /* PetscCall(PetscObjectSetName((PetscObject) y, "Frequency space vector")); */ 83 /* PetscCall(PetscObjectSetName((PetscObject) z, "Reconstructed vector")); */ 84 85 PetscCall(VecDestroy(&output)); 86 PetscCall(VecDestroy(&input)); 87 PetscCall(VecDestroy(&x)); 88 PetscCall(VecDestroy(&y)); 89 PetscCall(VecDestroy(&z)); 90 PetscCall(MatDestroy(&A)); 91 PetscCall(PetscRandomDestroy(&rdm)); 92 PetscCall(PetscFinalize()); 93 return 0; 94 } 95