https://github.com/JuliaLang/julia/issues/7089
> On Jun 2, 2014, at 7:44 PM, "Steven G. Johnson" <[email protected]> wrote: > >> On Monday, June 2, 2014 2:19:00 PM UTC-4, anonymousnoobie wrote: >> Does julia have a package or library to compute exponential integral >> >> http://en.wikipedia.org/wiki/Exponential_integral >> >> for real positive argument arbitrary precision ?? > > Yes, the exponential integral function is included with the MPFR library, > which is bundled with Julia and used for its BigFloat (arbitrary precision) > type. > > However, currently it's not exposed by a nice API, so you have to define: > > function eint(x::BigFloat) > z = BigFloat() > ccall((:mpfr_eint, :libmpfr), Int32, (Ptr{BigFloat}, Ptr{BigFloat}, > Int32), &z, &x, Base.MPFR.ROUNDING_MODE[end]) > return z > end > > and then you can do e.g. > > eint(big(2.2)) > > to compute Ei(2.2) in arbitrary precision. >
