1 static char help[] = "This program illustrates the use of PETSc-fftw interface for parallel real DFT\n"; 2 #include <petscmat.h> 3 #include <fftw3-mpi.h> 4 /*extern PetscErrorCode MatCreateVecsFFT(Mat,Vec *,Vec *,Vec *);*/ 5 int main(int argc, char **args) 6 { 7 PetscMPIInt rank, size; 8 PetscInt N0 = 4096, N1 = 4096, N2 = 256, N3 = 10, N4 = 10, N = N0 * N1; 9 PetscRandom rdm; 10 PetscReal enorm; 11 Vec x, y, z, input, output; 12 Mat A; 13 PetscInt DIM, dim[5], vsize, row, col; 14 PetscReal fac; 15 16 PetscFunctionBeginUser; 17 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 18 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 19 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 20 21 #if defined(PETSC_USE_COMPLEX) 22 SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "Example for Real DFT. Your current data type is complex!"); 23 #endif 24 PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &rdm)); 25 PetscCall(PetscRandomSetFromOptions(rdm)); 26 PetscCall(VecCreate(PETSC_COMM_WORLD, &input)); 27 PetscCall(VecSetSizes(input, PETSC_DECIDE, N)); 28 PetscCall(VecSetFromOptions(input)); 29 PetscCall(VecSetRandom(input, rdm)); 30 PetscCall(VecDuplicate(input, &output)); 31 32 DIM = 2; 33 dim[0] = N0; 34 dim[1] = N1; 35 dim[2] = N2; 36 dim[3] = N3; 37 dim[4] = N4; 38 PetscCall(MatCreateFFT(PETSC_COMM_WORLD, DIM, dim, MATFFTW, &A)); 39 PetscCall(MatGetLocalSize(A, &row, &col)); 40 printf("The Matrix size is %d and %d from process %d\n", row, col, rank); 41 PetscCall(MatCreateVecsFFTW(A, &x, &y, &z)); 42 43 PetscCall(VecGetSize(x, &vsize)); 44 45 PetscCall(VecGetSize(z, &vsize)); 46 printf("The vector size of output from the main routine is %d\n", vsize); 47 48 PetscCall(VecScatterPetscToFFTW(A, input, x)); 49 /*PetscCall(VecDestroy(&input));*/ 50 PetscCall(MatMult(A, x, y)); 51 PetscCall(MatMultTranspose(A, y, z)); 52 PetscCall(VecScatterFFTWToPetsc(A, z, output)); 53 /*PetscCall(VecDestroy(&z));*/ 54 fac = 1.0 / (PetscReal)N; 55 PetscCall(VecScale(output, fac)); 56 57 PetscCall(VecAssemblyBegin(input)); 58 PetscCall(VecAssemblyEnd(input)); 59 PetscCall(VecAssemblyBegin(output)); 60 PetscCall(VecAssemblyEnd(output)); 61 62 /* PetscCall(VecView(input,PETSC_VIEWER_STDOUT_WORLD));*/ 63 /* PetscCall(VecView(output,PETSC_VIEWER_STDOUT_WORLD));*/ 64 65 PetscCall(VecAXPY(output, -1.0, input)); 66 PetscCall(VecNorm(output, NORM_1, &enorm)); 67 if (enorm > 1.e-14) PetscCall(PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm)); 68 69 PetscCall(VecDestroy(&x)); 70 PetscCall(VecDestroy(&y)); 71 PetscCall(VecDestroy(&z)); 72 PetscCall(VecDestroy(&output)); 73 PetscCall(VecDestroy(&input)); 74 PetscCall(MatDestroy(&A)); 75 PetscCall(PetscRandomDestroy(&rdm)); 76 PetscCall(PetscFinalize()); 77 return 0; 78 } 79