Also, does eigs return the corresponding eigenvectors as well? //A
On Monday, January 26, 2015 at 5:41:44 PM UTC+1, Andrei Berceanu wrote: > > Indeed it seems to work with complex matrices as well. What would be very > useful for me is the ability to get eigenvalues within a certain interval, > emin to emax. I dont see this in the capabilities of eigs. > > //A > > On Monday, January 26, 2015 at 4:21:58 PM UTC+1, Andreas Noack wrote: >> >> Yes. There is some extra output including convergence information and the >> Ritz vectors. It should probably be explained in the manual, but the first >> argument is the values. You can avoid the vectors with ritzvec=false, so >> something like >> >> eigs(A, ritzvec = false)[1] >> >> should give you the largest (in magnitude) values. >> >> I think the documentation is simply wrong when stating that the matrix >> has to be real. I just tried a complex matrix and it worked just fine, so >> please open an issue about the documentation. >> >> 2015-01-26 10:03 GMT-05:00 Andrei Berceanu <andreib...@gmail.com>: >> >>> Besides, the help of eigs says "using Lanczos or Arnoldi iterations for >>> real symmetric or general nonsymmetric matrices respectively". Mine is >>> hermitian, i.e. complex and symmetric. >>> >>> >>> On Monday, January 26, 2015 at 4:02:16 PM UTC+1, Andrei Berceanu wrote: >>>> >>>> That seems to return a lot of things besides the eigenvalues. >>>> >>>> On Monday, January 26, 2015 at 3:43:01 PM UTC+1, Andreas Noack wrote: >>>>> >>>>> You can use eigs. Usually, you only ask for a few of the values, but >>>>> in theory, you could get all of them, but it could take some time to >>>>> compute them. >>>>> >>>>> 2015-01-26 9:40 GMT-05:00 Andrei Berceanu <andreib...@gmail.com>: >>>>> >>>>>> Is there any Julia function for computing the eigenvalues of a large, >>>>>> sparse, hermitian matrix M? I have tried eig(M) and eigvals(M) and got >>>>>> the >>>>>> "no method" error. >>>>>> >>>>>> //A >>>>>> >>>>> >>>>> >>
