At Tue, 5 Jan 2010 14:55:19 -0500, Gunjan Verma wrote: > When I run gsl_ran_fdist_pdf(.012, 8, 249) I get infinity. > But when I run > > gsl_ran_fdist_pdf(.012, 8, 248) I get .000074, which is correct (checked > against MATLAB and R) > > one d.f. change makes this difference - but I don't see why it should from > the formula for F pdf. > > i am running a Dell Latitude E6500 machine with ubuntu 9 linux , 64 bit and > gcc 4.4.1 . I built the gsl library from source for my system.
Thanks for the bug report. I can see the problem - there is a product of terms exp(A)*B*C where the exponential overflows. It needs to be rewritten as exp(A+log(B)+log(C)) when there is a danger of overflow. I've logged it as a bug to be fixed in the next release https://savannah.gnu.org/bugs/index.php?28500 -- Brian Gough GNU Scientific Library - http://www.gnu.org/software/gsl/ _______________________________________________ Bug-gsl mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-gsl
