2: #include <petscmat.h>

  4: #if !defined(PETSC_USE_COMPLEX)

  6: static char help[] = "Reads in a Symmetric matrix in MatrixMarket format. Writes\n\
  7: it using the PETSc sparse format. It also adds a Vector set to random values to the\n\
  8: output file. Input parameters are:\n\
  9:   -fin <filename> : input file\n\
 10:   -fout <filename> : output file\n\n";

 14: int main(int argc,char **args)
 15: {
 16:   Mat            A;
 17:   Vec            b;
 18:   char           filein[PETSC_MAX_PATH_LEN],fileout[PETSC_MAX_PATH_LEN],buf[PETSC_MAX_PATH_LEN];
 19:   PetscInt       i,m,n,nnz,col,row;
 21:   PetscMPIInt    size;
 22:   PetscScalar    val;
 23:   FILE           *file;
 24:   PetscViewer    view;
 25:   PetscRandom    r;

 27:   PetscInitialize(&argc,&args,(char*)0,help);

 29:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
 30:   if (size > 1) SETERRQ(PETSC_COMM_WORLD,1,"Uniprocessor Example only\n");

 32:   /* Read in matrix and RHS */
 33:   PetscOptionsGetString(NULL,"-fin",filein,PETSC_MAX_PATH_LEN,NULL);
 34:   PetscFOpen(PETSC_COMM_SELF,filein,"r",&file);

 36:   /* process header with comments */
 37:   do fgets(buf,PETSC_MAX_PATH_LEN-1,file);
 38:   while (buf[0] == '%');

 40:   /* The first non-comment line has the matrix dimensions */
 41:   sscanf(buf,"%d %d %d\n",&m,&n,&nnz);
 42:   printf ("m = %d, n = %d, nnz = %d\n",m,n,nnz);

 44:   MatCreateSeqAIJ(PETSC_COMM_WORLD,m,n,nnz*2/m,0,&A);
 45:   MatSetOption(A,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);
 46:   VecCreate(PETSC_COMM_WORLD,&b);
 47:   VecSetSizes(b,PETSC_DECIDE,n);
 48:   VecSetFromOptions(b);
 49:   PetscRandomCreate(PETSC_COMM_SELF,&r);
 50:   PetscRandomSetFromOptions(r);
 51:   VecSetRandom(b,r);

 53:   for (i=0; i<nnz; i++) {
 54:     fscanf(file,"%d %d %le\n",&row,&col,(double*)&val);
 55:     row  = row-1; col = col-1;
 56:     MatSetValues(A,1,&row,1,&col,&val,INSERT_VALUES);
 57:     if (row != col) {
 58:       MatSetValues(A,1,&col,1,&row,&val,INSERT_VALUES);
 59:     }
 60:   }
 61:   fclose(file);

 63:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 64:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 66:   PetscPrintf(PETSC_COMM_SELF,"Reading matrix completes.\n");
 67:   PetscOptionsGetString(NULL,"-fout",fileout,PETSC_MAX_PATH_LEN,NULL);
 68:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,fileout,FILE_MODE_WRITE,&view);
 69:   MatView(A,view);
 70:   VecView(b,view);
 71:   PetscViewerDestroy(&view);

 73:   VecDestroy(&b);
 74:   MatDestroy(&A);
 75:   PetscRandomDestroy(&r);

 77:   PetscFinalize();
 78:   return 0;
 79: }
 80: #else

 82: int main(int argc,char **args)
 83: {
 84:   fprintf(stdout,"This example does not work for complex numbers.\n");
 85:   return 0;
 86: }
 87: #endif