On Fri, Sep 06, 2013 at 03:02:18PM -0400, Mehmet Erol Sanliturk wrote: > On Fri, Sep 6, 2013 at 11:59 AM, Steve Kargl < > sgk_at_troutmask.apl.washington.edu> wrote: > > > > PS: I have working erfl and erfcl for ld80 archs. I'm still > > testing and refining the code. It turns out that computing > > the needed rational approximation is fairly difficult (at least > > for me). > > > Not only for you , because function values are not very "smooth" , and > representation by an approximation is very difficult . During many weeks , > I am trying to obtain good approximations to cumulative normal distribution > and its inverse , without very much success . > > Approximation to > inverse cumulative normal distribution is much more difficult than > cumulative normal distribution . > > I am using Fortran double precision . I think , it is necessary to use an > arbitrary precision package for optimization , but I do not have any one . > If you are using gfortran version 4.7 or newer on FreeBSD, you should be able to use a quad precision type. In addition, if you are using lang/gcc46 or newer on your FreeBSD system, then you have an arbitrary precision library installed (see math/mpfr). -- SteveReceived on Fri Sep 06 2013 - 17:48:59 UTC
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