Actual source code: ex18.c
petsc-3.12.0 2019-09-29
2: static char help[] = "Compares BLAS dots on different machines. Input\n\
3: arguments are\n\
4: -n <length> : local vector length\n\n";
7: #include <petscvec.h>
9: int main(int argc,char **argv)
10: {
12: PetscInt n = 15,i;
13: PetscScalar v;
14: Vec x,y;
16: PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
17: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
18: if (n < 5) n = 5;
21: /* create two vectors */
22: VecCreateSeq(PETSC_COMM_SELF,n,&x);
23: VecCreateSeq(PETSC_COMM_SELF,n,&y);
25: for (i=0; i<n; i++) {
26: v = ((PetscReal)i) + 1.0/(((PetscReal)i) + .35);
27: VecSetValues(x,1,&i,&v,INSERT_VALUES);
28: v += 1.375547826473644376;
29: VecSetValues(y,1,&i,&v,INSERT_VALUES);
30: }
31: VecAssemblyBegin(y);
32: VecAssemblyEnd(y);
34: VecDot(x,y,&v);
35: PetscFPrintf(PETSC_COMM_WORLD,stdout,"Vector inner product %16.12e\n",(double)PetscRealPart(v));
37: VecDestroy(&x);
38: VecDestroy(&y);
40: PetscFinalize();
41: return ierr;
42: }
46: /*TEST
48: test:
50: TEST*/