2011/11/8 Ondřej Čertík <[email protected]>: > On Tue, Nov 8, 2011 at 4:15 PM, Roberto Colistete Jr. > <[email protected]> wrote: >> Hi, >> >> On SymPy 0.6.7 the 'diff' function works on lists. But on SymPy >> 0.7.1 it doesn't, for example : >> >> In [1]: diff([cos(t), sin(t), exp(t), t) >> --------------------------------------------------------------------------- >> AttributeError Traceback (most recent call >> last) >> /home/roberto/<ipython-input-6-14d9fa9d6a32> in <module>() >> ----> 1 diff([cos(t),sin(t),t],t) >> >> /usr/local/lib/python2.6/dist-packages/sympy/core/function.pyc in >> diff(f, *symbols, **kwargs) >> 1104 """ >> 1105 kwargs.setdefault('evaluate', True) >> -> 1106 return Derivative(f, *symbols, **kwargs) >> 1107 >> 1108 def expand(e, deep=True, modulus=None, power_base=True, >> power_exp=True, \ >> >> /usr/local/lib/python2.6/dist-packages/sympy/core/function.pyc in >> __new__(cls, expr, *symbols, **assumptions) >> 672 if evaluate: >> 673 if set(sc[0] for sc in symbol_count >> --> 674 ).difference(expr.free_symbols): >> 675 return S.Zero >> 676 >> >> AttributeError: 'list' object has no attribute 'free_symbols' > > > ^^^ I was getting this "no attribute 'free_symbols'" error couple > times when I was trying to integrate something (I think). The error is > not informative and the code should be refactored to produce a > readable error message showing what is wrong and why. > > The above error message looks like a bug in sympy. > > Ondrej
If you got this by using regular SymPy input, then it is definitely a bug. The problem here was that the input was not SymPy input, so any function that assumes that it is would fail (and also, currently sympify() does nothing to lists). Aaron Meurer -- 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.
