MUSL math functions

[Steve Kargl]

On Fri, Nov 01, 2013 at 07:52:27AM +1100, Bruce Evans wrote:
> On Thu, 31 Oct 2013, Steve Kargl wrote:
>> On Thu, Oct 31, 2013 at 10:46:15AM +0000, David Chisnall wrote:
>>>
>>> erfcl, erfl
>>
>> I have code for erfcl and erfl.
> 
> cerfl (not in C99) is apparently amazingly complicated.  There is a
> whole library libcerf for it on the net.

openlibm includes http://ab-initio.mit.edu/wiki/index.php/Faddeeva_Package
I haven't looked into the quality.  The webpage claims 13 significant
digits, which is not quite good enough for double.

> erf support is very patchy in calculators.  See the list in the NIST
> web pages that update Abramowicz and Stegun.  I find it hard to test
> since it is not in pari.

MPFR has implementations for erf and erfc.  Testing on flame is
extremely slow due to this.  I think that I've only tested
around 50000 values in the non-asymptotic range.

-- 
Steve