These are chat archives for symengine/symengine

30th
Oct 2018
Richard Otis
@richardotis
Oct 30 2018 22:26

On the currently released dev version:

import sympy
from symengine.lib.symengine_wrapper import Piecewise
from symengine import Pow, S, GreaterThan, Lambdify

x = sympy.symarray('x', 3)
expr = Piecewise((S.One, GreaterThan(x[1], 1e-12)), (S.Zero, True))
print(expr)
func = Lambdify(x, expr)
Traceback (most recent call last):
  File "test_model.py", line 8, in <module>
    func = Lambdify(x, expr)
  File "symengine_wrapper.pyx", line 4793, in symengine.lib.symengine_wrapper.Lambdify
  File "symengine_wrapper.pyx", line 4481, in symengine.lib.symengine_wrapper._Lambdify.__init__
  File "symengine_wrapper.pyx", line 4671, in symengine.lib.symengine_wrapper.LambdaDouble._init
RuntimeError: Not Implemented

It isn't clear exactly what isn't implemented. It appears to be something to do with how Piecewise and Relational interact

Isuru Fernando
@isuruf
Oct 30 2018 23:50
@richardotis, works for me in master