Actual source code: ex18.c

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

  5: #include <petscvec.h>

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

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

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

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

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

 34:   PetscCall(VecDestroy(&x));
 35:   PetscCall(VecDestroy(&y));

 37:   PetscCall(PetscFinalize());
 38:   return 0;
 39: }

 41: /*TEST

 43:    test:

 45: TEST*/