1c4762a1bSJed Brown static char help[]="This program illustrates the use of PETSc-fftw interface for real 2D DFT.\n\ 2c4762a1bSJed Brown See ~petsc/src/mat/tests/ex158.c for general cases. \n\n"; 3c4762a1bSJed Brown 4c4762a1bSJed Brown #include <petscmat.h> 5c4762a1bSJed Brown 6c4762a1bSJed Brown int main(int argc,char **args) 7c4762a1bSJed Brown { 8c4762a1bSJed Brown PetscErrorCode ierr; 9c4762a1bSJed Brown PetscMPIInt rank,size; 10c4762a1bSJed Brown PetscInt N0=50,N1=50,N=N0*N1; 11c4762a1bSJed Brown PetscRandom rdm; 12c4762a1bSJed Brown PetscReal enorm; 13c4762a1bSJed Brown Vec x,y,z,input,output; 14c4762a1bSJed Brown Mat A; 15c4762a1bSJed Brown PetscInt DIM,dim[2]; 16c4762a1bSJed Brown PetscReal fac; 17c4762a1bSJed Brown 18c4762a1bSJed Brown ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr; 19c4762a1bSJed Brown #if defined(PETSC_USE_COMPLEX) 20c4762a1bSJed Brown SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers"); 21c4762a1bSJed Brown #endif 22c4762a1bSJed Brown 23*ffc4695bSBarry Smith ierr = MPI_Comm_size(PETSC_COMM_WORLD, &size);CHKERRMPI(ierr); 24*ffc4695bSBarry Smith ierr = MPI_Comm_rank(PETSC_COMM_WORLD, &rank);CHKERRMPI(ierr); 25c4762a1bSJed Brown 26c4762a1bSJed Brown /* Create and set PETSc vectors 'input' and 'output' */ 27c4762a1bSJed Brown ierr = PetscRandomCreate(PETSC_COMM_WORLD, &rdm);CHKERRQ(ierr); 28c4762a1bSJed Brown ierr = PetscRandomSetFromOptions(rdm);CHKERRQ(ierr); 29c4762a1bSJed Brown 30c4762a1bSJed Brown ierr = VecCreate(PETSC_COMM_WORLD,&input);CHKERRQ(ierr); 31c4762a1bSJed Brown ierr = VecSetSizes(input,PETSC_DECIDE,N0*N1);CHKERRQ(ierr); 32c4762a1bSJed Brown ierr = VecSetFromOptions(input);CHKERRQ(ierr); 33c4762a1bSJed Brown ierr = VecSetRandom(input,rdm);CHKERRQ(ierr); 34c4762a1bSJed Brown ierr = VecDuplicate(input,&output);CHKERRQ(ierr); 35c4762a1bSJed Brown ierr = PetscObjectSetName((PetscObject)input, "Real space vector");CHKERRQ(ierr); 36c4762a1bSJed Brown ierr = PetscObjectSetName((PetscObject)output, "Reconstructed vector");CHKERRQ(ierr); 37c4762a1bSJed Brown 38c4762a1bSJed Brown /* Get FFTW vectors 'x', 'y' and 'z' */ 39c4762a1bSJed Brown DIM = 2; 40c4762a1bSJed Brown dim[0] = N0; dim[1] = N1; 41c4762a1bSJed Brown ierr = MatCreateFFT(PETSC_COMM_WORLD,DIM,dim,MATFFTW,&A);CHKERRQ(ierr); 42c4762a1bSJed Brown ierr = MatCreateVecsFFTW(A,&x,&y,&z);CHKERRQ(ierr); 43c4762a1bSJed Brown 44c4762a1bSJed Brown /* Scatter PETSc vector 'input' to FFTW vector 'x' */ 45c4762a1bSJed Brown ierr = VecScatterPetscToFFTW(A,input,x);CHKERRQ(ierr); 46c4762a1bSJed Brown 47c4762a1bSJed Brown /* Apply forward FFT */ 48c4762a1bSJed Brown ierr = MatMult(A,x,y);CHKERRQ(ierr); 49c4762a1bSJed Brown 50c4762a1bSJed Brown /* Apply backward FFT */ 51c4762a1bSJed Brown ierr = MatMultTranspose(A,y,z);CHKERRQ(ierr); 52c4762a1bSJed Brown 53c4762a1bSJed Brown /* Scatter FFTW vector 'z' to PETSc vector 'output' */ 54c4762a1bSJed Brown ierr = VecScatterFFTWToPetsc(A,z,output);CHKERRQ(ierr); 55c4762a1bSJed Brown 56c4762a1bSJed Brown /* Check accuracy */ 57c4762a1bSJed Brown fac = 1.0/(PetscReal)N; 58c4762a1bSJed Brown ierr = VecScale(output,fac);CHKERRQ(ierr); 59c4762a1bSJed Brown ierr = VecAXPY(output,-1.0,input);CHKERRQ(ierr); 60c4762a1bSJed Brown ierr = VecNorm(output,NORM_1,&enorm);CHKERRQ(ierr); 61c4762a1bSJed Brown if (enorm > 1.e-11 && !rank) { 62c4762a1bSJed Brown ierr = PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm);CHKERRQ(ierr); 63c4762a1bSJed Brown } 64c4762a1bSJed Brown 65c4762a1bSJed Brown /* Free spaces */ 66c4762a1bSJed Brown ierr = PetscRandomDestroy(&rdm);CHKERRQ(ierr); 67c4762a1bSJed Brown ierr = VecDestroy(&input);CHKERRQ(ierr); 68c4762a1bSJed Brown ierr = VecDestroy(&output);CHKERRQ(ierr); 69c4762a1bSJed Brown ierr = VecDestroy(&x);CHKERRQ(ierr); 70c4762a1bSJed Brown ierr = VecDestroy(&y);CHKERRQ(ierr); 71c4762a1bSJed Brown ierr = VecDestroy(&z);CHKERRQ(ierr); 72c4762a1bSJed Brown ierr = MatDestroy(&A);CHKERRQ(ierr); 73c4762a1bSJed Brown 74c4762a1bSJed Brown ierr = PetscFinalize(); 75c4762a1bSJed Brown return ierr; 76c4762a1bSJed Brown } 77c4762a1bSJed Brown 78c4762a1bSJed Brown 79c4762a1bSJed Brown 80c4762a1bSJed Brown 81c4762a1bSJed Brown 82c4762a1bSJed Brown /*TEST 83c4762a1bSJed Brown 84c4762a1bSJed Brown build: 85c4762a1bSJed Brown requires: fftw !complex 86c4762a1bSJed Brown 87c4762a1bSJed Brown test: 88c4762a1bSJed Brown output_file: output/ex148.out 89c4762a1bSJed Brown 90c4762a1bSJed Brown test: 91c4762a1bSJed Brown suffix: 2 92c4762a1bSJed Brown nsize: 3 93c4762a1bSJed Brown output_file: output/ex148.out 94c4762a1bSJed Brown 95c4762a1bSJed Brown TEST*/ 96