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; 41 dim[1] = N1; 42 dim[2] = N2; 43 dim[3] = N3; 44 dim[4] = N4; 45 46 PetscCall(MatCreateFFT(PETSC_COMM_WORLD, DIM, dim, MATFFTW, &A)); 47 PetscCall(MatCreateVecs(A, &x, &y)); 48 PetscCall(MatCreateVecs(A, &z, NULL)); 49 PetscCall(VecGetSize(x, &vsize)); 50 printf("The vector size from the main routine is %d\n", vsize); 51 52 PetscCall(InputTransformFFT(A, input, x)); 53 54 PetscCall(MatMult(A, x, y)); 55 PetscCall(VecAssemblyBegin(y)); 56 PetscCall(VecAssemblyEnd(y)); 57 PetscCall(VecView(y, PETSC_VIEWER_STDOUT_WORLD)); 58 PetscCall(MatMultTranspose(A, y, z)); 59 PetscCall(VecGetSize(z, &vsize)); 60 printf("The vector size of zfrom the main routine is %d\n", vsize); 61 62 PetscCall(OutputTransformFFT(A, z, output)); 63 64 fac = 1.0 / (PetscReal)N; 65 PetscCall(VecScale(output, fac)); 66 67 PetscCall(VecAssemblyBegin(input)); 68 PetscCall(VecAssemblyEnd(input)); 69 PetscCall(VecAssemblyBegin(output)); 70 PetscCall(VecAssemblyEnd(output)); 71 72 PetscCall(VecView(input, PETSC_VIEWER_STDOUT_WORLD)); 73 PetscCall(VecView(output, PETSC_VIEWER_STDOUT_WORLD)); 74 75 PetscCall(VecAXPY(output, -1.0, input)); 76 PetscCall(VecNorm(output, NORM_1, &enorm)); 77 /* if (enorm > 1.e-14) { */ 78 if (rank == 0) PetscCall(PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm)); 79 /* } */ 80 81 /* PetscCall(MatCreateVecs(A,&z,NULL)); */ 82 /* printf("Vector size from ex148 %d\n",vsize); */ 83 /* PetscCall(PetscObjectSetName((PetscObject) x, "Real space vector")); */ 84 /* PetscCall(PetscObjectSetName((PetscObject) y, "Frequency space vector")); */ 85 /* PetscCall(PetscObjectSetName((PetscObject) z, "Reconstructed vector")); */ 86 87 PetscCall(VecDestroy(&output)); 88 PetscCall(VecDestroy(&input)); 89 PetscCall(VecDestroy(&x)); 90 PetscCall(VecDestroy(&y)); 91 PetscCall(VecDestroy(&z)); 92 PetscCall(MatDestroy(&A)); 93 PetscCall(PetscRandomDestroy(&rdm)); 94 PetscCall(PetscFinalize()); 95 return 0; 96 } 97