Context: I want to evaluate a symbolic expression numerically; however sometimes this expression still depends on some symbolic parameters not yet assigned a value.
Question: What is the best way to avoid "TypeError: cannot evaluate symbolic expression numerically" in such a situation?
In other words, is there a function (or an equivalent construction) for
if isThisSymbolicExpressionNumericallyEvaluabel(exp):
n = exp.n()
else:
print "sorry, no"
