The matrix is 1681x1681 with 8240 non-zero entries (i.e. 0.29% non-zero). I'm not sure how this relates to your second comment though :)
On Monday, January 26, 2015 at 5:48:37 PM UTC+1, Andreas Noack wrote: > > How large is the matrix and what is the sparsity? > > You might be able to get closer to what you want by using shifts in eigs. > Then you'll get the values closest to the value of the shift. > > 2015-01-26 11:41 GMT-05:00 Andrei Berceanu <andreib...@gmail.com > <javascript:>>: > >> 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 >>>>>>> >>>>>> >>>>>> >>> >
