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 PetscErrorCode ierr; 10 PetscMPIInt rank,size; 11 PetscInt N0=3,N1=3,N2=3,N=N0*N1*N2; 12 PetscRandom rdm; 13 PetscScalar a; 14 PetscReal enorm; 15 Vec x,y,z,input,output; 16 PetscBool view=PETSC_FALSE,use_interface=PETSC_TRUE; 17 Mat A; 18 PetscInt DIM, dim[3],vsize; 19 PetscReal fac; 20 21 ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr; 22 #if defined(PETSC_USE_COMPLEX) 23 SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers"); 24 #endif 25 26 ierr = MPI_Comm_size(PETSC_COMM_WORLD, &size);CHKERRQ(ierr); 27 ierr = MPI_Comm_rank(PETSC_COMM_WORLD, &rank);CHKERRQ(ierr); 28 29 30 ierr = PetscRandomCreate(PETSC_COMM_WORLD, &rdm);CHKERRQ(ierr); 31 ierr = PetscRandomSetFromOptions(rdm);CHKERRQ(ierr); 32 33 ierr = VecCreate(PETSC_COMM_WORLD,&input);CHKERRQ(ierr); 34 ierr = VecSetSizes(input,PETSC_DECIDE,N);CHKERRQ(ierr); 35 ierr = VecSetFromOptions(input);CHKERRQ(ierr); 36 ierr = VecSetRandom(input,rdm);CHKERRQ(ierr); 37 ierr = VecDuplicate(input,&output); 38 /* ierr = VecGetSize(input,&vsize);CHKERRQ(ierr); */ 39 /* printf("Size of the input Vector is %d\n",vsize); */ 40 41 DIM = 3; 42 dim[0] = N0; dim[1] = N1; dim[2] = N2; 43 44 ierr = MatCreateFFT(PETSC_COMM_WORLD,DIM,dim,MATFFTW,&A);CHKERRQ(ierr); 45 ierr = MatCreateVecs(A,&x,&y);CHKERRQ(ierr); 46 ierr = MatCreateVecs(A,&z,NULL);CHKERRQ(ierr); 47 ierr = VecGetSize(y,&vsize);CHKERRQ(ierr); 48 printf("The vector size from the main routine is %d\n",vsize); 49 50 ierr = InputTransformFFT(A,input,x);CHKERRQ(ierr); 51 ierr = MatMult(A,x,y);CHKERRQ(ierr); 52 ierr = MatMultTranspose(A,y,z);CHKERRQ(ierr); 53 ierr = OutputTransformFFT(A,z,output);CHKERRQ(ierr); 54 55 fac = 1.0/(PetscReal)N; 56 ierr = VecScale(output,fac);CHKERRQ(ierr); 57 58 ierr = VecAssemblyBegin(input);CHKERRQ(ierr); 59 ierr = VecAssemblyEnd(input);CHKERRQ(ierr); 60 ierr = VecAssemblyBegin(output);CHKERRQ(ierr); 61 ierr = VecAssemblyEnd(output);CHKERRQ(ierr); 62 63 ierr = VecView(input,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 64 ierr = VecView(output,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 65 66 ierr = VecAXPY(output,-1.0,input);CHKERRQ(ierr); 67 ierr = VecNorm(output,NORM_1,&enorm);CHKERRQ(ierr); 68 /* if (enorm > 1.e-14) { */ 69 if (!rank) { 70 ierr = PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm);CHKERRQ(ierr); 71 } 72 /* } */ 73 74 75 76 77 /* ierr = MatCreateVecs(A,&z,NULL);CHKERRQ(ierr); */ 78 /* printf("Vector size from ex148 %d\n",vsize); */ 79 /* ierr = PetscObjectSetName((PetscObject) x, "Real space vector");CHKERRQ(ierr); */ 80 /* ierr = PetscObjectSetName((PetscObject) y, "Frequency space vector");CHKERRQ(ierr); */ 81 /* ierr = PetscObjectSetName((PetscObject) z, "Reconstructed vector");CHKERRQ(ierr); */ 82 83 ierr = PetscFinalize(); 84 return ierr; 85 86 } 87 88 89 90