A first Cython interface for libgiac

This gives a python class (Pygen) which works with pointer to giac gen. There is a version for python and another one for sage.

The Giac/Xcas Forum is a good place to ask questions about giacpy.

The pure python version: (description)

• Sources of the python version : tarballs and zip files of giacpy sources can be downloaded from the giacpy GIT repository

To have graphic support, you first need to build the libqcas (qmake libqcas.pro;make). then on linux install giacpy with:

python setup.py install ( or just build it with: ) python setup.py build_ext

• Debian Packages  are avaible in Giac/Xcas debian repository:

  Chose python-giacpy for python2.x or python3-giacpy for Python3.

  But if your python version/subversion is not supported in these debian package look here:
  
  Some Linux binaries (ex: for python 3.5)

  The python version and subversion must match yours, and the architecture (32bits/64bits) too. The .whl or .tar.gz are just 2 different ways to distribute the same thing.

• MacOsX version of giacpy

Choose the appropirate version : On macosx 10.6 the default python version is 2.6, and for osx 10.7 and 10.8 it is python 2.7. The .pkg files are macosx installer. They require adminitrator rights. If you can't install giacpy from the .pkg files, then you can consider giacpy.dmg. It is a portable version of giacpy and can be installed anywhere. But you will need to adjust your python path. Cf the README file in giacpy.app.

• Windows binaries of giacpy are now avaible (as wheels) on Pypi
  
  To install the giacpy wheel on windows from pypi:
  python.exe -mpip install giacpy

  NB: recent versions of giacpy are currently compiled without Qcas output for older windows binaries: (x86 Python win32) and (x86_64 Python win64).
  To install giacpy on windows (old way), choose the version adapted to your python version (Python version,subversion and 32/64bits should match; example python 3.4 32bits) and install giacpy in the directory Lib/site-packages of your Python installation. If you are not allowed to do this, put giacpy anywhere and do as in exemple.py.
  NB: The french keywords might not be functional with the windows version of giacpy.

The sage version of giacpy: giacpy_sage

New style spkg of giacpy_sage:

• The GIT repository and giacpy_sage tar balls

Installation:

Some differences with the python version of giacpy:

Only: Pygen,libgiac,giacsettings,loadgiacgen are exported by import *. (There are too many words in sage that whould be overwriten. ex gcd...)

The qcas output, htmlhelp are disabled. It has some extra features like Pygen gets sage Integers directly from mpz_t,

Warning. in sage the giac command calls the external giac program. To use this interface use libgiac.

Some sage/giacpy Examples :

• The sage doc for giacpy

• Some Timings for Groebner Basis in sage with magma/giacpy and multithreading. and the sage worksheet

• Groebner basis over QQ of cyclic9 in sage with giacpy and magma and the sage worksheet
  

  The magma 2.20-10 result was not imported in sage.
  The computation is around 7h or 8h of Wall time, but 49h of CPU time for giacpy.
  On a server with /home mounted via nfs, the giacpy result is saved to a 1.1G file in 28s, loaded in 68s, converted to a list of sage polynomials in 170s. The saved giacpy computation can be compared in sage with the magma result. (pdf or sage worksheet)

• Other examples (including mod p) of groebner basis with giacpy from sage: A sage worksheet or the pdf screenshot)

  Ex Katsura12 mod 65521 takes 90s

• Formal determinant, libgiac magic mode examples and tests A sage worksheet or the pdf screenshot)

• A non trivial determinantal relation in many variables A sage worksheet or the pdf screenshot)

• Formal calculus and basic plots the sage worksheet or the pdf screenshot)

Examples with giacpy_sage

from giacpy_sage import *
libgiac.ifactor(2**128+1)
x,y=libgiac('x,y')
cos(x+y).texpand()
n=9;R=PolynomialRing(QQ,n,'x');
I = sage.rings.ideal.Katsura(R,n);
I.gens()
time B = I.groebner_basis("libsingular:std") # to compute with singular. about 18s on my notebook.
giacsettings.proba_epsilon=1e-15;
Igiac=libgiac(I.gens());
time Bgiac=Igiac.gbasis([R.gens()],'revlex') # about 3s on my notebook
simplify(Bgiac[-1]/B[0])
giacsettings.proba_epsilon=0; # impose deterministic algorithm
Igiac=libgiac(I.gens());
time Bgiac=Igiac.gbasis([R.gens()],'revlex') # about 25s on my notebook
simplify(Bgiac[-1]/B[0]) # a big constant

Or if your sage is too old or you want a particular version of giacpy:

sage setup.py install