Upgrade to cypari2

realalg/algebraic.py

@@ -6,13 +6,21 @@
 from math import log10 as log
 from numbers import Integral
 
-import cypari as cp
 import sympy as sp
+try:
+    import cypari2
+    cp = cypari2.Pari()
+except ImportError:
+    try:
+        import cypari
+        cp = cypari.pari
+    except ImportError:
+        raise Exception("You need to install cypari or cypari2 to use the realalg module. Try pip install cypari2.")
 
 from .interval import Interval
 
 sp_x = sp.Symbol('x')
-cp_x = cp.pari('x')
+cp_x = cp('x')
 
 def log_plus(x):
     ''' Return the height of the number ``x``. '''
@@ -24,7 +32,7 @@ def sp_polynomial(coefficients):
 
 def cp_polynomial(coefficients):
     ''' Return the cypari polynomial with the given coefficients. '''
-    return cp.pari(' + '.join('{}*x^{}'.format(coefficient, index) for index, coefficient in enumerate(coefficients)))
+    return cp(' + '.join('{}*x^{}'.format(coefficient, index) for index, coefficient in enumerate(coefficients)))
 
 class RealNumberField(object):
     ''' Represents the NumberField QQ(lmbda) = QQ[x] / << f(x) >> where lmbda is a real root of f(x). '''

setup.py

@@ -5,8 +5,10 @@
 
 from setuptools import setup, find_packages
 
+# We need one of cypari or cypari2 to interface with PARI. Since we do not
+# want to lock in the user to either version explicitly, we do not add a
+# dependency here but complain at runtime if neither can be found.
 requirements = [
-    'cypari',
     'sympy',
 ]
 

tox.ini

@@ -15,6 +15,7 @@ deps =
     hypothesis
     pytest
     pytest-cov
+    cypari
 commands =
     py.test {posargs}