[Gretl-users] Re: eiggen2(), Re() and Im()

Am 10.01.2020 um 22:02 schrieb Allin Cottrell: > On Fri, 10 Jan 2020, Allin Cottrell wrote: > >> 3) I'm not so sure about Sven's suggestion that (if I'm understanding >> him right) sqrt(M), for M a real matrix with some negative elements, >> should return an appropriate complex matrix. It's clearly defensible, >> but it might produce surprising/puzzling results in some cases so I >> think it requires further discussion. > First of all, yes I understand what you mean, it would have some downsides, too. > In the meantime, it's not difficult to get what you want in this sort > of case, if you know what you're doing. Example: > > <hansl> > matrix B = {1,-4; -9,1} > print B > eval sqrt(complex(B,0)) > </hansl> I was thinking of the same approach, but didn't know that a simple 0 was enough and would broadcast.