pynac.pyx use double precision special functions instead of long double

[mwhansen]

Many systems such as cygwin don't have the long double version. Plus, they are being applied to floats/doubles so the extra precision doesn't buy much.

Component: porting: Cygwin

Keywords: pynac

Author: Mike Hansen

Reviewer: Burcin Erocal, Mike Hansen, William Stein

Merged: sage-4.4.3.alpha0

Issue created by migration from https://trac.sagemath.org/ticket/8847

[mwhansen]

Attachment: trac_8847.patch.gz

[burcin]

Reviewer: Burcin Erocal

[burcin]

comment:2

This gives the following doctest failures on my 64-bit T9300 Core 2 Duo laptop, with gcc (Gentoo 4.3.4 p1.0, pie-10.1.5) 4.3.4 and glibc-2.10.1. I have no idea what is relevant, so I give some random information. :)

**********************************************************************
File "/home/burcin/sage/sage-4.4.1.alpha2-patched/devel/sage-t/sage/functions/other.py", line 428:
    sage: gamma1(float(6))
Expected:
    120.0
Got:
    119.99999999999997
**********************************************************************

**********************************************************************
File "/home/burcin/sage/sage-4.4.1.alpha2-patched/devel/sage-t/sage/symbolic/expression.pyx", line 5318:
    sage: SR(10.0r).gamma()
Expected:
    362880.0
Got:
    362880.00000000047
**********************************************************************

[burcin]

Changed keywords from none to pynac

[mwhansen]

comment:3

It'd be nice if we could just do like an ifdef in Cython.

[burcin]

comment:4

We can put the ifdef in c_lib/include/ginac_wrapper.h to define the long double versions on Cygwin. Initially, they could just wrap the double precision functions.

[williamstein]

comment:5

I just did something at runtime using a bint. It's very simple, and will have a very minimal performance hit.

[williamstein]

apply only this (not the one below)

[williamstein]

Attachment: trac_8847-take2.patch.gz

Attachment: trac_8847-take3.patch.gz

[mwhansen]

Attachment: trac_8847-take4.patch.gz

[williamstein]

Merged: 4.4.3.alpha0

[williamstein]

Changed reviewer from Burcin Erocal to Burcin Erocal, Mike Hansen, William Stein

[sagetrac-mvngu]

Changed merged from 4.4.3.alpha0 to sage-4.4.3.alpha0