2: static char help[] = "Reads in a matrix and vector in ASCII format. Writes\n\
  3: them using the PETSc sparse format. Input parameters are:\n\
  4:   -fin <filename> : input file\n\
  5:   -fout <filename> : output file\n\n";

  7: #include <petscmat.h>

 11: int main(int argc,char **args)
 12: {
 13:   Mat            A;
 14:   Vec            b;
 15:   char           filein[PETSC_MAX_PATH_LEN],finname[PETSC_MAX_PATH_LEN],fileout[PETSC_MAX_PATH_LEN];
 16:   PetscInt       n,col,row,rowin;
 18:   PetscBool      flg;
 19:   PetscScalar    val,*array;
 20:   FILE           *file;
 21:   PetscViewer    view;

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

 25:   /* Read in matrix and RHS */
 26:   PetscOptionsGetString(NULL,"-fin",filein,256,&flg);
 27:   if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate file for reading");
 28:   PetscOptionsGetString(NULL,"-fout",fileout,256,&flg);
 29:   if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate file for writing");

 31:   PetscFixFilename(filein,finname);
 32:   if (!(file = fopen(finname,"r"))) SETERRQ(PETSC_COMM_SELF,1,"cannot open input file\n");
 33:   fscanf(file,"%d\n",&n);

 35:   MatCreate(PETSC_COMM_WORLD,&A);
 36:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
 37:   MatSetFromOptions(A);
 38:   VecCreate(PETSC_COMM_WORLD,&b);
 39:   VecSetSizes(b,PETSC_DECIDE,n);
 40:   VecSetFromOptions(b);

 42:   for (row=0; row<n; row++) {
 43:     fscanf(file,"row %d:",&rowin);
 44:     if (rowin != row) SETERRQ(PETSC_COMM_SELF,1,"Bad file");
 45:     while (fscanf(file," %d %le",&col,(double*)&val)) {
 46:       MatSetValues(A,1,&row,1,&col,&val,INSERT_VALUES);
 47:     }
 48:   }
 49:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 50:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
 51:   VecGetArray(b,&array);
 52:   for (row=0; row<n; row++) {
 53:     fscanf(file," ii= %d %le",&col,(double*)(array+row));
 54:   }
 55:   VecRestoreArray(b,&array);

 57:   fclose(file);

 59:   PetscPrintf(PETSC_COMM_SELF,"Reading matrix complete.\n");
 60:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,fileout,FILE_MODE_WRITE,&view);
 61:   MatView(A,view);
 62:   VecView(b,view);
 63:   PetscViewerDestroy(&view);

 65:   VecDestroy(&b);
 66:   MatDestroy(&A);

 68:   PetscFinalize();
 69:   return 0;
 70: }