Re: [deal.II] Re: Computing min and max eigenvalues

On 10/25/2018 05:23 AM, Michał Wichrowski wrote: > > I think the documentation of arpack solver is not valid: > https://www.dealii.org/developer/doxygen/deal.II/classArpackSolver.html#afdc3aa9d761c43b5b4132e731c6191a5 > A The operator for which we want to compute eigenvalues. Actually, this >

Re: [deal.II] Re: Computing min and max eigenvalues

Earl, I am posing this question purely out of personal interest: what do you mean > by maximum and minimum eigenvalue? I am confused by this. > > The eigenvalues with largest and smallest magnitude. My problem is symmetric positive-definite, thus the spectrum is real and positive, so in my ca

Re: [deal.II] Re: Computing min and max eigenvalues

I am posing this question purely out of personal interest: what do you mean by maximum and minimum eigenvalue? I am confused by this. Earl On Tue, Oct 23, 2018 at 8:36 AM Michał Wichrowski wrote: > > Dear Bruno > >> >> > 2) The largest eigenvalue is computed instead of the largest one, and, >

Re: [deal.II] Re: Computing min and max eigenvalues

Dear Bruno > > > 2) The largest eigenvalue is computed instead of the largest one, and, I > guess, the smallest eigenvalue is computed instead of the largest one. > If you use ARPACK through deal without patching it, then the only > method available is shift-inverse. The thing is that when you

Re: [deal.II] Re: Computing min and max eigenvalues

Michal, Le ven. 19 oct. 2018 à 06:33, Michał Wichrowski a écrit : > 1) The number of iterations and residual are obviously strange. I guess that > ARPACK solver does not update SlolverControl object That's correct. SolverControl is used to set ARPACK's parameters but it is not updated by ARPACK

[deal.II] Re: Computing min and max eigenvalues

PS. I noticed that in some cases the "smallest" eigenvalue does not match maximum eigenvalue obtained from power method. -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message

[deal.II] Re: Computing min and max eigenvalues

Dear Bruno, I've used ARPACK and the computation time has dropped signifficantly. But I have some strange results, I have following code: IterationNumberControl arpack_control(30, 1e-8); typename ArpackSolver::AdditionalData arpack_data_smallest(30,

[deal.II] Re: Computing min and max eigenvalues

W dniu czwartek, 18 października 2018 17:59:40 UTC+2 użytkownik Bruno Turcksin napisał: > > Michal, > > Have you tried to use ARPACK to get the smallest eigenvalues? That's what > we are doing in one of our code and it works pretty well. We have a patch > here >

[deal.II] Re: Computing min and max eigenvalues

Michal, Have you tried to use ARPACK to get the smallest eigenvalues? That's what we are doing in one of our code and it works pretty well. We have a patch here so that you don't need to provide t