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 int main(int argc,char **args) 5 { 6 PetscErrorCode ierr; 7 PetscMPIInt rank,size; 8 PetscInt N0=2048,N1=2048,N2=3,N3=5,N4=5,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; 14 PetscReal fac; 15 PetscScalar one=1,two=2,three=3; 16 17 ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr; 18 #if defined(PETSC_USE_COMPLEX) 19 SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers"); 20 #endif 21 ierr = MPI_Comm_size(PETSC_COMM_WORLD, &size);CHKERRMPI(ierr); 22 ierr = MPI_Comm_rank(PETSC_COMM_WORLD, &rank);CHKERRMPI(ierr); 23 24 ierr = PetscRandomCreate(PETSC_COMM_WORLD, &rdm);CHKERRQ(ierr); 25 ierr = PetscRandomSetFromOptions(rdm);CHKERRQ(ierr); 26 ierr = VecCreate(PETSC_COMM_WORLD,&input);CHKERRQ(ierr); 27 ierr = VecSetSizes(input,PETSC_DECIDE,N);CHKERRQ(ierr); 28 ierr = VecSetFromOptions(input);CHKERRQ(ierr); 29 /* ierr = VecSet(input,one);CHKERRQ(ierr); */ 30 /* ierr = VecSetValue(input,1,two,INSERT_VALUES);CHKERRQ(ierr); */ 31 /* ierr = VecSetValue(input,2,three,INSERT_VALUES);CHKERRQ(ierr); */ 32 /* ierr = VecSetValue(input,3,three,INSERT_VALUES);CHKERRQ(ierr); */ 33 ierr = VecSetRandom(input,rdm);CHKERRQ(ierr); 34 /* ierr = VecSetRandom(input,rdm);CHKERRQ(ierr); */ 35 /* ierr = VecSetRandom(input,rdm);CHKERRQ(ierr); */ 36 ierr = VecDuplicate(input,&output);CHKERRQ(ierr); 37 38 DIM = 2; dim[0] = N0; dim[1] = N1; dim[2] = N2; dim[3] = N3; dim[4] = N4; 39 ierr = MatCreateFFT(PETSC_COMM_WORLD,DIM,dim,MATFFTW,&A);CHKERRQ(ierr); 40 ierr = MatCreateVecsFFTW(A,&x,&y,&z);CHKERRQ(ierr); 41 /* ierr = MatCreateVecs(A,&x,&y);CHKERRQ(ierr); */ 42 /* ierr = MatCreateVecs(A,&z,NULL);CHKERRQ(ierr); */ 43 44 ierr = VecGetSize(x,&vsize);CHKERRQ(ierr); 45 printf("The vector size of input from the main routine is %d\n",vsize); 46 47 ierr = VecGetSize(z,&vsize);CHKERRQ(ierr); 48 printf("The vector size of output from the main routine is %d\n",vsize); 49 50 ierr = InputTransformFFT(A,input,x);CHKERRQ(ierr); 51 52 ierr = MatMult(A,x,y);CHKERRQ(ierr); 53 ierr = VecAssemblyBegin(y);CHKERRQ(ierr); 54 ierr = VecAssemblyEnd(y);CHKERRQ(ierr); 55 ierr = VecView(y,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 56 57 ierr = MatMultTranspose(A,y,z);CHKERRQ(ierr); 58 59 ierr = OutputTransformFFT(A,z,output);CHKERRQ(ierr); 60 fac = 1.0/(PetscReal)N; 61 ierr = VecScale(output,fac);CHKERRQ(ierr); 62 63 ierr = VecAssemblyBegin(input);CHKERRQ(ierr); 64 ierr = VecAssemblyEnd(input);CHKERRQ(ierr); 65 ierr = VecAssemblyBegin(output);CHKERRQ(ierr); 66 ierr = VecAssemblyEnd(output);CHKERRQ(ierr); 67 68 /* ierr = VecView(input,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); */ 69 /* ierr = VecView(output,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); */ 70 71 ierr = VecAXPY(output,-1.0,input);CHKERRQ(ierr); 72 ierr = VecNorm(output,NORM_1,&enorm);CHKERRQ(ierr); 73 /* if (enorm > 1.e-14) { */ 74 ierr = PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm);CHKERRQ(ierr); 75 /* } */ 76 77 ierr = VecDestroy(&output);CHKERRQ(ierr); 78 ierr = VecDestroy(&input);CHKERRQ(ierr); 79 ierr = VecDestroy(&x);CHKERRQ(ierr); 80 ierr = VecDestroy(&y);CHKERRQ(ierr); 81 ierr = VecDestroy(&z);CHKERRQ(ierr); 82 ierr = MatDestroy(&A);CHKERRQ(ierr); 83 ierr = PetscRandomDestroy(&rdm);CHKERRQ(ierr); 84 ierr = PetscFinalize(); 85 return ierr; 86 87 } 88