1 2 static char help[] = "Reads a matrix from PETSc binary file. Use for view or investigating matrix data structure. \n\n"; 3 /* 4 Example: 5 ./ex16 -f <matrix file> -a_mat_view draw -draw_pause -1 6 ./ex16 -f <matrix file> -a_mat_view ascii::ascii_info 7 */ 8 9 #include <petscmat.h> 10 int main(int argc,char **args) 11 { 12 Mat A,Asp; 13 PetscViewer fd; /* viewer */ 14 char file[PETSC_MAX_PATH_LEN]; /* input file name */ 15 PetscErrorCode ierr; 16 PetscInt m,n,rstart,rend; 17 PetscBool flg; 18 PetscInt row,ncols,j,nrows,nnzA=0,nnzAsp=0; 19 const PetscInt *cols; 20 const PetscScalar *vals; 21 PetscReal norm,percent,val,dtol=1.e-16; 22 PetscMPIInt rank; 23 MatInfo matinfo; 24 PetscInt Dnnz,Onnz; 25 26 27 ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr; 28 ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr); 29 30 /* Determine files from which we read the linear systems. */ 31 ierr = PetscOptionsGetString(NULL,NULL,"-f",file,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr); 32 if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -f option"); 33 34 /* Open binary file. Note that we use FILE_MODE_READ to indicate 35 reading from this file. */ 36 ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);CHKERRQ(ierr); 37 38 /* Load the matrix; then destroy the viewer. */ 39 ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr); 40 ierr = MatSetOptionsPrefix(A,"a_");CHKERRQ(ierr); 41 ierr = MatSetFromOptions(A);CHKERRQ(ierr); 42 ierr = MatLoad(A,fd);CHKERRQ(ierr); 43 ierr = PetscViewerDestroy(&fd);CHKERRQ(ierr); 44 ierr = MatGetSize(A,&m,&n);CHKERRQ(ierr); 45 ierr = MatGetInfo(A,MAT_LOCAL,&matinfo);CHKERRQ(ierr); 46 /*printf("matinfo.nz_used %g\n",matinfo.nz_used);*/ 47 48 /* Get a sparse matrix Asp by dumping zero entries of A */ 49 ierr = MatCreate(PETSC_COMM_WORLD,&Asp);CHKERRQ(ierr); 50 ierr = MatSetSizes(Asp,m,n,PETSC_DECIDE,PETSC_DECIDE);CHKERRQ(ierr); 51 ierr = MatSetOptionsPrefix(Asp,"asp_");CHKERRQ(ierr); 52 ierr = MatSetFromOptions(Asp);CHKERRQ(ierr); 53 Dnnz = (PetscInt)matinfo.nz_used/m + 1; 54 Onnz = Dnnz/2; 55 printf("Dnnz %d %d\n",Dnnz,Onnz); 56 ierr = MatSeqAIJSetPreallocation(Asp,Dnnz,NULL);CHKERRQ(ierr); 57 ierr = MatMPIAIJSetPreallocation(Asp,Dnnz,NULL,Onnz,NULL);CHKERRQ(ierr); 58 /* The allocation above is approximate so we must set this option to be permissive. 59 * Real code should preallocate exactly. */ 60 ierr = MatSetOption(Asp,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_FALSE);CHKERRQ(ierr); 61 62 /* Check zero rows */ 63 ierr = MatGetOwnershipRange(A,&rstart,&rend);CHKERRQ(ierr); 64 nrows = 0; 65 for (row=rstart; row<rend; row++) { 66 ierr = MatGetRow(A,row,&ncols,&cols,&vals);CHKERRQ(ierr); 67 nnzA += ncols; 68 norm = 0.0; 69 for (j=0; j<ncols; j++) { 70 val = PetscAbsScalar(vals[j]); 71 if (norm < val) norm = norm; 72 if (val > dtol) { 73 ierr = MatSetValues(Asp,1,&row,1,&cols[j],&vals[j],INSERT_VALUES);CHKERRQ(ierr); 74 nnzAsp++; 75 } 76 } 77 if (!norm) nrows++; 78 ierr = MatRestoreRow(A,row,&ncols,&cols,&vals);CHKERRQ(ierr); 79 } 80 ierr = MatAssemblyBegin(Asp,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 81 ierr = MatAssemblyEnd(Asp,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 82 83 percent=(PetscReal)nnzA*100/(m*n); 84 ierr = PetscPrintf(PETSC_COMM_SELF," [%d] Matrix A local size %d,%d; nnzA %d, %g percent; No. of zero rows: %d\n",rank,m,n,nnzA,percent,nrows); 85 percent=(PetscReal)nnzAsp*100/(m*n); 86 ierr = PetscPrintf(PETSC_COMM_SELF," [%d] Matrix Asp nnzAsp %d, %g percent\n",rank,nnzAsp,percent); 87 88 /* investigate matcoloring for Asp */ 89 PetscBool Asp_coloring = PETSC_FALSE; 90 ierr = PetscOptionsHasName(NULL,NULL,"-Asp_color",&Asp_coloring);CHKERRQ(ierr); 91 if (Asp_coloring) { 92 MatColoring mc; 93 ISColoring iscoloring; 94 MatFDColoring matfdcoloring; 95 ierr = PetscPrintf(PETSC_COMM_WORLD," Create coloring of Asp...\n"); 96 ierr = MatColoringCreate(Asp,&mc);CHKERRQ(ierr); 97 ierr = MatColoringSetType(mc,MATCOLORINGSL);CHKERRQ(ierr); 98 ierr = MatColoringSetFromOptions(mc);CHKERRQ(ierr); 99 ierr = MatColoringApply(mc,&iscoloring);CHKERRQ(ierr); 100 ierr = MatColoringDestroy(&mc);CHKERRQ(ierr); 101 ierr = MatFDColoringCreate(Asp,iscoloring,&matfdcoloring);CHKERRQ(ierr); 102 ierr = MatFDColoringSetFromOptions(matfdcoloring);CHKERRQ(ierr); 103 ierr = MatFDColoringSetUp(Asp,iscoloring,matfdcoloring);CHKERRQ(ierr); 104 /*ierr = MatFDColoringView(matfdcoloring,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);*/ 105 ierr = ISColoringDestroy(&iscoloring);CHKERRQ(ierr); 106 ierr = MatFDColoringDestroy(&matfdcoloring);CHKERRQ(ierr); 107 } 108 109 /* Write Asp in binary for study - see ~petsc/src/mat/tests/ex124.c */ 110 PetscBool Asp_write = PETSC_FALSE; 111 ierr = PetscOptionsHasName(NULL,NULL,"-Asp_write",&Asp_write);CHKERRQ(ierr); 112 if (Asp_write) { 113 PetscViewer viewer; 114 ierr = PetscPrintf(PETSC_COMM_SELF,"Write Asp into file Asp.dat ...\n"); 115 ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,"Asp.dat",FILE_MODE_WRITE,&viewer);CHKERRQ(ierr); 116 ierr = MatView(Asp,viewer);CHKERRQ(ierr); 117 ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr); 118 } 119 120 ierr = MatDestroy(&A);CHKERRQ(ierr); 121 ierr = MatDestroy(&Asp);CHKERRQ(ierr); 122 ierr = PetscFinalize(); 123 return ierr; 124 } 125 126