Re: [gentoo-science] [sage-on-gentoo] cannot build Sage because of Sympy-0.7.1

[Francois Bissey <fbissey@slingshot.co.nz>]

On Fri, 17 Aug 2012 12:20:12 v_2e@ukr.net wrote:
>   Hello!
> 
> On Fri, 17 Aug 2012 09:32:18 +1200
> 
> fbissey@slingshot.co.nz wrote:
> > OK wrong assumption from me by looking at the code. You have probably
> > enabled the gmp useflag in mpmath and now you have gmpy on your
> > system. I am now fairly
> > sure that gmpy is the cause of the problem.
> > Like sage gmpy can be autoloaded by mpmath but if both are present at
> > the same time  you get the confusion that you have seen.
> 
>   Yes, the 'gmp' USE-flag is enabled for 'mpmath'.
> 
> > As a quick check you can try: MPMATH_NOGMPY=1 emerge -1v sympy
> > that should work. Adding that variable to sage-env may help with
> > potential problems importing mpmath or sympy in sage but really
> > mpmath has to change their default behavior.
> 
>   So what do I have to do to have a working Sage? Do I have to rebuild
> 'mpmath' with the 'gmp' USE-flag disabled?
> 
Best solution: rebuild mpmath without the gmp useflag and remove gmpy.
Rebuilding is not enough as the flag only insure that gmpy is installed.
mpmath autodetect gmpy's presence all by itself if it is present - gmp flag or 
not.

If you don't want to do that you'll have to export MPMATH_NOGMPY=1
before using sage or emerging sympy or importing sympy or mpmath
from the python shell.

Francois