Actual source code: ex141.c
petsc-3.4.2 2013-07-02

      2: static char help[] = "Tests converting a SBAIJ matrix to BAIJ format with MatCovert. Modified from ex55.c\n\n";

      4: #include <petscmat.h>
      5: /* Usage: ./ex141 -mat_view */

      9: int main(int argc,char **args)
     10: {
     11:   Mat            C,B;
     13:   PetscInt       i,bs=2,mbs,m,block,d_nz=6,col[3];
     14:   PetscMPIInt    size;
     15:   char           file[PETSC_MAX_PATH_LEN];
     16:   PetscViewer    fd;
     17:   PetscBool      equal,loadmat;
     18:   PetscScalar    value[4];
     19:   PetscInt       ridx[2],cidx[2];

     21:   PetscInitialize(&argc,&args,(char*)0,help);
     22:   PetscOptionsGetString(NULL,"-f",file,PETSC_MAX_PATH_LEN,&loadmat);
     23:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
     24:   if (size != 1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"This is a uniprocessor example only!");

     26:   /* input matrix C */
     27:   if (loadmat) {
     28:     /* Open binary file. Load a sbaij matrix, then destroy the viewer. */
     29:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);
     30:     MatCreate(PETSC_COMM_WORLD,&C);
     31:     MatSetType(C,MATSEQSBAIJ);
     32:     MatLoad(C,fd);
     33:     PetscViewerDestroy(&fd);
     34:   } else { /* Create a sbaij mat with bs>1  */
     35:     mbs  =8;
     36:     PetscOptionsGetInt(NULL,"-mbs",&mbs,NULL);
     37:     m    = mbs*bs;
     38:     MatCreate(PETSC_COMM_WORLD,&C);
     39:     MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m,m);
     40:     MatSetType(C,MATSBAIJ);
     41:     MatSetFromOptions(C);
     42:     MatSeqSBAIJSetPreallocation(C,bs,d_nz,NULL);
     43:     MatSetUp(C);
     44:     MatSetOption(C,MAT_IGNORE_LOWER_TRIANGULAR,PETSC_TRUE);

     46:     for (block=0; block<mbs; block++) {
     47:       /* diagonal blocks */
     48:       value[0] = -1.0; value[1] = 4.0; value[2] = -1.0;
     49:       for (i=1+block*bs; i<bs-1+block*bs; i++) {
     50:         col[0] = i-1; col[1] = i; col[2] = i+1;
     51:         MatSetValues(C,1,&i,3,col,value,INSERT_VALUES);
     52:       }
     53:       i = bs - 1+block*bs; col[0] = bs - 2+block*bs; col[1] = bs - 1+block*bs;

     55:       value[0]=-1.0; value[1]=4.0;
     56:       MatSetValues(C,1,&i,2,col,value,INSERT_VALUES);

     58:       i = 0+block*bs; col[0] = 0+block*bs; col[1] = 1+block*bs;

     60:       value[0]=4.0; value[1] = -1.0;
     61:       MatSetValues(C,1,&i,2,col,value,INSERT_VALUES);
     62:     }
     63:     /* off-diagonal blocks */
     64:     value[0]=-1.0; value[1] = -0.1; value[2] = 0.0; value[3] = -1.0; /* row-oriented */
     65:     for (block=0; block<mbs-1; block++) {
     66:       for (i=0; i<bs; i++) {
     67:         ridx[i] = block*bs+i; cidx[i] = (block+1)*bs+i;
     68:       }
     69:       MatSetValues(C,bs,ridx,bs,cidx,value,INSERT_VALUES);
     70:     }
     71:     MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
     72:     MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
     73:   }

     75:   /* convert C to BAIJ format */
     76:   MatConvert(C,MATSEQBAIJ,MAT_INITIAL_MATRIX,&B);
     77:   MatMultEqual(B,C,10,&equal);
     78:   if (!equal) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"MatConvert fails!");

     80:   MatDestroy(&B);
     81:   MatDestroy(&C);
     82:   PetscFinalize();
     83:   return 0;
     84: }