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