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;
14: PetscFunctionBeginUser;
15: PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
16: PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
17: if (n < 5) n = 5;
19: /* create two vectors */
20: PetscCall(VecCreateSeq(PETSC_COMM_SELF, n, &x));
21: PetscCall(VecCreateSeq(PETSC_COMM_SELF, n, &y));
23: for (i = 0; i < n; i++) {
24: v = ((PetscReal)i) + 1.0 / (((PetscReal)i) + .35);
25: PetscCall(VecSetValues(x, 1, &i, &v, INSERT_VALUES));
26: v += 1.375547826473644376;
27: PetscCall(VecSetValues(y, 1, &i, &v, INSERT_VALUES));
28: }
29: PetscCall(VecAssemblyBegin(y));
30: PetscCall(VecAssemblyEnd(y));
32: PetscCall(VecDot(x, y, &v));
33: PetscCall(PetscFPrintf(PETSC_COMM_WORLD, stdout, "Vector inner product %16.12e\n", (double)PetscRealPart(v)));
35: PetscCall(VecDestroy(&x));
36: PetscCall(VecDestroy(&y));
38: PetscCall(PetscFinalize());
39: return 0;
40: }
42: /*TEST
44: test:
46: TEST*/