Yes, they are Hermitian. On Thu, Sep 21, 2017 at 3:43 PM Hong <[email protected]> wrote:
> Greg: > > OK, the difference is whether LU or Cholesky factorization is used. But I >> would hope that neither one should give incorrect eigenvalues, and when I >> run with the latter it does! >> > Are your matrices symmetric/Hermitian? > Hong > >> >> On Thu, Sep 21, 2017 at 2:05 PM Hong <[email protected]> wrote: >> >>> Gregory : >>> Use '-eps_view' for both runs to check the algorithms being used. >>> Hong >>> >>> Hi all, >>>> >>>> I'm using shift-invert with EPS to solve for eigenvalues. I find that >>>> if I do only >>>> >>>> ... >>>> ierr = EPSGetST(eps,&st);CHKERRQ(ierr); >>>> ierr = STSetType(st,STSINVERT);CHKERRQ(ierr); >>>> ... >>>> >>>> in my code I get correct eigenvalues. But if I do >>>> >>>> ... >>>> ierr = EPSGetST(eps,&st);CHKERRQ(ierr); >>>> ierr = STSetType(st,STSINVERT);CHKERRQ(ierr); >>>> ierr = STGetKSP(st,&ksp);CHKERRQ(ierr); >>>> ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr); >>>> ierr = KSPSetType(ksp,KSPPREONLY);CHKERRQ(ierr); >>>> ierr = PCSetType(pc,PCCHOLESKY);CHKERRQ(ierr); >>>> ... >>>> >>>> the eigenvalues found by EPS are completely wrong! Somehow I thought I >>>> was supposed to do the latter, from the examples etc, but I guess that was >>>> not correct? I attach the full piece of test code and a test matrix. >>>> >>>> Best, >>>> Greg >>>> >>> >>>
