Actual source code: ex18.c


  2: static char help[] = "Compares BLAS dots on different machines. Input\n\
  3: arguments are\n\
  4:   -n <length> : local vector length\n\n";

  6: #include <petscvec.h>

  8: int main(int argc, char **argv)
  9: {
 10:   PetscInt    n = 15, i;
 11:   PetscScalar v;
 12:   Vec         x, y;

 15:   PetscInitialize(&argc, &argv, (char *)0, help);
 16:   PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL);
 17:   if (n < 5) n = 5;

 19:   /* create two vectors */
 20:   VecCreateSeq(PETSC_COMM_SELF, n, &x);
 21:   VecCreateSeq(PETSC_COMM_SELF, n, &y);

 23:   for (i = 0; i < n; i++) {
 24:     v = ((PetscReal)i) + 1.0 / (((PetscReal)i) + .35);
 25:     VecSetValues(x, 1, &i, &v, INSERT_VALUES);
 26:     v += 1.375547826473644376;
 27:     VecSetValues(y, 1, &i, &v, INSERT_VALUES);
 28:   }
 29:   VecAssemblyBegin(y);
 30:   VecAssemblyEnd(y);

 32:   VecDot(x, y, &v);
 33:   PetscFPrintf(PETSC_COMM_WORLD, stdout, "Vector inner product %16.12e\n", (double)PetscRealPart(v));

 35:   VecDestroy(&x);
 36:   VecDestroy(&y);

 38:   PetscFinalize();
 39:   return 0;
 40: }

 42: /*TEST

 44:    test:

 46: TEST*/