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 { 6 PetscMPIInt rank, size; 7 PetscInt N0 = 10, N1 = 10, N2 = 10, N3 = 10, N4 = 10, N = N0 * N1 * N2 * N3 * N4; 8 PetscRandom rdm; 9 PetscReal enorm; 10 Vec x, y, z, input, output; 11 Mat A; 12 PetscInt DIM, dim[5], vsize; 13 PetscReal fac; 14 15 PetscFunctionBeginUser; 16 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 17 #if defined(PETSC_USE_COMPLEX) 18 SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "This example requires real numbers"); 19 #endif 20 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 21 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 22 23 PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "This is a uni-processor example only"); 24 PetscCall(PetscRandomCreate(PETSC_COMM_SELF, &rdm)); 25 PetscCall(PetscRandomSetFromOptions(rdm)); 26 PetscCall(VecCreate(PETSC_COMM_SELF, &input)); 27 PetscCall(VecSetSizes(input, N, N)); 28 PetscCall(VecSetFromOptions(input)); 29 PetscCall(VecSetRandom(input, rdm)); 30 PetscCall(VecDuplicate(input, &output)); 31 32 DIM = 5; 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_SELF, DIM, dim, MATFFTW, &A)); 39 PetscCall(MatCreateVecs(A, &x, &y)); 40 PetscCall(MatCreateVecs(A, &z, NULL)); 41 42 PetscCall(VecGetSize(x, &vsize)); 43 printf("The vector size of input from the main routine is %d\n", 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(InputTransformFFT(A, input, x)); 49 50 PetscCall(MatMult(A, x, y)); 51 PetscCall(MatMultTranspose(A, y, z)); 52 53 PetscCall(OutputTransformFFT(A, z, output)); 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) { */ 68 PetscCall(PetscPrintf(PETSC_COMM_SELF, " Error norm of |x - z| %e\n", enorm)); 69 /* } */ 70 71 PetscCall(VecDestroy(&output)); 72 PetscCall(VecDestroy(&input)); 73 PetscCall(VecDestroy(&x)); 74 PetscCall(VecDestroy(&y)); 75 PetscCall(VecDestroy(&z)); 76 PetscCall(MatDestroy(&A)); 77 PetscCall(PetscRandomDestroy(&rdm)); 78 PetscCall(PetscFinalize()); 79 return 0; 80 } 81