Check if Sympy Expression is Nan?
In sympy, you can check for equality with the sympy nan object:
>>> alpha = sympy.nan
>>> alpha == sympy.nan
True
In numpy, you cannot check for equality with the numpy nan object:
>>> alpha = numpy.nan
>>> alpha == numpy.nan
False
>>> numpy.isnan(alpha)
True
Hence there exists a numpy.isnan() method, and there does not exist a sympy.isnan() method.
Credit to Morgan Thrapp
In SymPy, ==
always checks structural equality (that is, if two expressions are exactly equal). This works even for nan, so there is no need for a separate isnan
function (strictly speaking, SymPy's nan isn't an IEEE 754 nan).