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 PetscMPIInt rank, size; 9 PetscInt N0 = 3, N1 = 3, N2 = 3, N3 = 3, N4 = 3, N = N0 * N1 * N2 * N3; 10 PetscRandom rdm; 11 PetscReal enorm; 12 Vec x, y, z, input, output; 13 Mat A; 14 PetscInt DIM, dim[5], vsize; 15 PetscReal fac; 16 PetscScalar one = 1; 17 18 PetscFunctionBeginUser; 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; 40 dim[1] = N1; 41 dim[2] = N2; 42 dim[3] = N3; 43 dim[4] = N4; 44 45 PetscCall(MatCreateFFT(PETSC_COMM_WORLD, DIM, dim, MATFFTW, &A)); 46 PetscCall(MatCreateVecs(A, &x, &y)); 47 PetscCall(MatCreateVecs(A, &z, NULL)); 48 PetscCall(VecGetSize(x, &vsize)); 49 printf("The vector size from the main routine is %d\n", vsize); 50 51 PetscCall(InputTransformFFT(A, input, x)); 52 53 PetscCall(MatMult(A, x, y)); 54 PetscCall(VecAssemblyBegin(y)); 55 PetscCall(VecAssemblyEnd(y)); 56 PetscCall(VecView(y, PETSC_VIEWER_STDOUT_WORLD)); 57 PetscCall(MatMultTranspose(A, y, z)); 58 PetscCall(VecGetSize(z, &vsize)); 59 printf("The vector size of zfrom the main routine is %d\n", vsize); 60 61 PetscCall(OutputTransformFFT(A, z, output)); 62 63 fac = 1.0 / (PetscReal)N; 64 PetscCall(VecScale(output, fac)); 65 66 PetscCall(VecAssemblyBegin(input)); 67 PetscCall(VecAssemblyEnd(input)); 68 PetscCall(VecAssemblyBegin(output)); 69 PetscCall(VecAssemblyEnd(output)); 70 71 PetscCall(VecView(input, PETSC_VIEWER_STDOUT_WORLD)); 72 PetscCall(VecView(output, PETSC_VIEWER_STDOUT_WORLD)); 73 74 PetscCall(VecAXPY(output, -1.0, input)); 75 PetscCall(VecNorm(output, NORM_1, &enorm)); 76 /* if (enorm > 1.e-14) { */ 77 if (rank == 0) { PetscCall(PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm)); } 78 /* } */ 79 80 /* PetscCall(MatCreateVecs(A,&z,NULL)); */ 81 /* printf("Vector size from ex148 %d\n",vsize); */ 82 /* PetscCall(PetscObjectSetName((PetscObject) x, "Real space vector")); */ 83 /* PetscCall(PetscObjectSetName((PetscObject) y, "Frequency space vector")); */ 84 /* PetscCall(PetscObjectSetName((PetscObject) z, "Reconstructed vector")); */ 85 86 PetscCall(VecDestroy(&output)); 87 PetscCall(VecDestroy(&input)); 88 PetscCall(VecDestroy(&x)); 89 PetscCall(VecDestroy(&y)); 90 PetscCall(VecDestroy(&z)); 91 PetscCall(MatDestroy(&A)); 92 PetscCall(PetscRandomDestroy(&rdm)); 93 PetscCall(PetscFinalize()); 94 return 0; 95 } 96