When something like this happens, it's a bug. Everything in SymPy should work just the same if you swap out different names for symbols, with the exception that some things might be ordered differently.
In this case, it looks like the bug has already been fixed, so it should work just fine in the upcoming 0.7.2 release, or in the development version. Aaron Meurer On Thu, Sep 6, 2012 at 12:04 PM, Marc Massar <[email protected]> wrote: > Hi, > > I found an integral that sometimes fails, sometime succeeds depending on the > variable name. See the session below. > > How can I avoid such unexpected behavior? > > This is with SymPy 0.7.1 on windows. > > Thanks in advance. > > IPython console for SymPy 0.7.1 (Python 2.7.2-32-bit) (ground types: python) > > These commands were executed: >>>> from __future__ import division >>>> from sympy import * >>>> x, y, z, t = symbols('x y z t') >>>> k, m, n = symbols('k m n', integer=True) >>>> f, g, h = symbols('f g h', cls=Function) > > Documentation can be found at http://www.sympy.org > > In [1]: x,a=symbols('x a') > > In [2]: integrate(exp(-(a**2+a)/2),(a,-oo,oo)) > Out[2]: > oo > / > | > | 2 > | a a > | - -- - - > | 2 2 > | e da > | > / > -oo > > In [3]: integrate(exp(-(x**2+x)/2),(x,-oo,oo)) > Out[3]: > ___ ____ 1/8 > \/ 2 *\/ pi *e > > In [4]: > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To view this discussion on the web visit > https://groups.google.com/d/msg/sympy/-/YNstfGtJjAkJ. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
