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, N = N0 * N1 * N2; 10 PetscRandom rdm; 11 PetscScalar a; 12 PetscReal enorm; 13 Vec x, y, z, input, output; 14 PetscBool view = PETSC_FALSE, use_interface = PETSC_TRUE; 15 Mat A; 16 PetscInt DIM, dim[3], vsize; 17 PetscReal fac; 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 31 PetscCall(VecCreate(PETSC_COMM_WORLD, &input)); 32 PetscCall(VecSetSizes(input, PETSC_DECIDE, N)); 33 PetscCall(VecSetFromOptions(input)); 34 PetscCall(VecSetRandom(input, rdm)); 35 PetscCall(VecDuplicate(input, &output)); 36 /* PetscCall(VecGetSize(input,&vsize)); */ 37 /* printf("Size of the input Vector is %d\n",vsize); */ 38 39 DIM = 3; 40 dim[0] = N0; 41 dim[1] = N1; 42 dim[2] = N2; 43 44 PetscCall(MatCreateFFT(PETSC_COMM_WORLD, DIM, dim, MATFFTW, &A)); 45 PetscCall(MatCreateVecs(A, &x, &y)); 46 PetscCall(MatCreateVecs(A, &z, NULL)); 47 PetscCall(VecGetSize(y, &vsize)); 48 printf("The vector size from the main routine is %d\n", vsize); 49 50 PetscCall(InputTransformFFT(A, input, x)); 51 PetscCall(MatMult(A, x, y)); 52 PetscCall(MatMultTranspose(A, y, z)); 53 PetscCall(OutputTransformFFT(A, z, output)); 54 55 fac = 1.0 / (PetscReal)N; 56 PetscCall(VecScale(output, fac)); 57 58 PetscCall(VecAssemblyBegin(input)); 59 PetscCall(VecAssemblyEnd(input)); 60 PetscCall(VecAssemblyBegin(output)); 61 PetscCall(VecAssemblyEnd(output)); 62 63 PetscCall(VecView(input, PETSC_VIEWER_STDOUT_WORLD)); 64 PetscCall(VecView(output, PETSC_VIEWER_STDOUT_WORLD)); 65 66 PetscCall(VecAXPY(output, -1.0, input)); 67 PetscCall(VecNorm(output, NORM_1, &enorm)); 68 /* if (enorm > 1.e-14) { */ 69 if (rank == 0) PetscCall(PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm)); 70 /* } */ 71 72 /* PetscCall(MatCreateVecs(A,&z,NULL)); */ 73 /* printf("Vector size from ex148 %d\n",vsize); */ 74 /* PetscCall(PetscObjectSetName((PetscObject) x, "Real space vector")); */ 75 /* PetscCall(PetscObjectSetName((PetscObject) y, "Frequency space vector")); */ 76 /* PetscCall(PetscObjectSetName((PetscObject) z, "Reconstructed vector")); */ 77 78 PetscCall(PetscFinalize()); 79 return 0; 80 } 81