On 2014-03-26, Paul Mercat <merc...@yahoo.fr> wrote: > > > Le mercredi 26 mars 2014 20:48:32 UTC+1, Dima Pasechnik a écrit : >> >> On 2014-03-26, Paul Mercat <mer...@yahoo.fr <javascript:>> wrote: >> > I need to compute charpoly of big sparse matrices obtained in sage, but >> > there is no efficient algorithm in sage for the moment. >> > So I would like to implement it and add it to sage. >> > I think it already exists in gp or in linbox, but I was not able to use >> it >> > in sage. >> > Maybe sage has no proper way to convert a sparse matrix to give it to gp >> or >> > to linbox ? >> > Does somebody knows how to do that ? >> >> what kind of field are your matrices defined over? >> >> >> > I have matrices with non negative integers. > Is there a efficient way to get the exact Perron-Frobenius spectral radius > of these sparse matrices in sage ?
Do I understand you right that you are talking about a generalisation of the usual Perron-Frobenius for matrices with positive entries? Do you really need to now the whole exact characteristic polynomial? This looks like an overkill, and won't possibly work for big matrices (if by "big" you mean something like 1000x1000 or more...) IMHO, at least in the case of irreducible matrices, one computes the dominant eigenvector by the power method, and from it one can find (an approximation of) the maximal eigenvalue. > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
