1 static char help[] = "This program illustrates the use of PETSc-fftw interface for sequential real DFT\n"; 2 #include <petscmat.h> 3 #include <fftw3-mpi.h> 4 int main(int argc, char **args) { 5 PetscMPIInt rank, size; 6 PetscInt N0 = 10, N1 = 10, N2 = 10, N3 = 10, N4 = 10, N = N0 * N1 * N2 * N3 * N4; 7 PetscRandom rdm; 8 PetscReal enorm; 9 Vec x, y, z, input, output; 10 Mat A; 11 PetscInt DIM, dim[5], vsize; 12 PetscReal fac; 13 14 PetscFunctionBeginUser; 15 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 16 #if defined(PETSC_USE_COMPLEX) 17 SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "This example requires real numbers"); 18 #endif 19 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 20 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 21 22 PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "This is a uni-processor example only"); 23 PetscCall(PetscRandomCreate(PETSC_COMM_SELF, &rdm)); 24 PetscCall(PetscRandomSetFromOptions(rdm)); 25 PetscCall(VecCreate(PETSC_COMM_SELF, &input)); 26 PetscCall(VecSetSizes(input, N, N)); 27 PetscCall(VecSetFromOptions(input)); 28 PetscCall(VecSetRandom(input, rdm)); 29 PetscCall(VecDuplicate(input, &output)); 30 31 DIM = 5; 32 dim[0] = N0; 33 dim[1] = N1; 34 dim[2] = N2; 35 dim[3] = N3; 36 dim[4] = N4; 37 PetscCall(MatCreateFFT(PETSC_COMM_SELF, DIM, dim, MATFFTW, &A)); 38 PetscCall(MatCreateVecs(A, &x, &y)); 39 PetscCall(MatCreateVecs(A, &z, NULL)); 40 41 PetscCall(VecGetSize(x, &vsize)); 42 printf("The vector size of input from the main routine is %d\n", vsize); 43 44 PetscCall(VecGetSize(z, &vsize)); 45 printf("The vector size of output from the main routine is %d\n", vsize); 46 47 PetscCall(InputTransformFFT(A, input, x)); 48 49 PetscCall(MatMult(A, x, y)); 50 PetscCall(MatMultTranspose(A, y, z)); 51 52 PetscCall(OutputTransformFFT(A, z, output)); 53 fac = 1.0 / (PetscReal)N; 54 PetscCall(VecScale(output, fac)); 55 /* 56 PetscCall(VecAssemblyBegin(input)); 57 PetscCall(VecAssemblyEnd(input)); 58 PetscCall(VecAssemblyBegin(output)); 59 PetscCall(VecAssemblyEnd(output)); 60 61 PetscCall(VecView(input,PETSC_VIEWER_STDOUT_WORLD)); 62 PetscCall(VecView(output,PETSC_VIEWER_STDOUT_WORLD)); 63 */ 64 PetscCall(VecAXPY(output, -1.0, input)); 65 PetscCall(VecNorm(output, NORM_1, &enorm)); 66 /* if (enorm > 1.e-14) { */ 67 PetscCall(PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm)); 68 /* } */ 69 70 PetscCall(VecDestroy(&output)); 71 PetscCall(VecDestroy(&input)); 72 PetscCall(VecDestroy(&x)); 73 PetscCall(VecDestroy(&y)); 74 PetscCall(VecDestroy(&z)); 75 PetscCall(MatDestroy(&A)); 76 PetscCall(PetscRandomDestroy(&rdm)); 77 PetscCall(PetscFinalize()); 78 return 0; 79 } 80