[petsc-users] Passing array of PETSc Vec's to a function and returning it

[rmondaini at csrc.ac.cn]

I am trying to pass an array of Vec's in PETSc to a function, modify it 
internally and retrieve the results. The idea is to copy a handful of 
eigenvectors from the EPS solver to the main routine. A pseudocode is as 
follows:

#include <slepceps.h>

     PetscErrorCode foo(Vec **y, int n) {

         EPS            eps;         // eigenproblem solver context

        // ...

         ierr = MatCreateVecs(H, &x, NULL); CHKERRQ(ierr);

         ierr = EPSSolve(eps); CHKERRQ(ierr);

     // ...

       ierr = VecDuplicateVecs(x, n, y); CHKERRQ(ierr);

        for (int i = 0; i < n ; i++) {    // I can guarantee that n < nconv

            ierr = EPSGetEigenvector(eps, i, *y[i], NULL); 
CHKERRQ(ierr);   // this breaks for i = 1

            ierr = VecNorm(*y[i],NORM_2,&norm); CHKERRQ(ierr);   // this 
prints out fine for i = 0 (norm = 1)

            printf("norm = %f\n", norm);

         }

         ierr = EPSDestroy(&eps); CHKERRQ(ierr);
         ierr = VecDestroy(&x); CHKERRQ(ierr);

         return ierr;

     }

     int main(int argc,char **argv)
     {
         PetscErrorCode ierr;
         PetscScalar norm;
         Vec *y;

         foo(&y, 3);

         ierr = VecDestroyVecs(3, &y); CHKERRQ(ierr);

         return 0;
     }

Am I making a naive mistake here?