Probably you are requesting more eigenvectors than actually computed. Argument
i should be smaller than nconv, see
https://slepc.upv.es/documentation/current/docs/manualpages/EPS/EPSGetEigenvector.html
Jose
> El 22 jul 2020, a las 10:25, rmonda...@csrc.ac.cn escribió:
>
> 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?
>
