.. classmethod:: fromsympy(expr)
Create a linear expression from a :mod:`sympy` expression.
- Raise :exc:`ValueError` is the :mod:`sympy` expression is not linear.
+ Raise :exc:`TypeError` is the :mod:`sympy` expression is not linear.
.. method:: tosympy()
Compute the *standard widening* of two polyhedra, à la Halbwachs.
+ In its current implementation, this method is slow and should not be used on large polyhedra.
+
.. data:: Empty
.. method:: cross(vector)
Compute the cross product of two 3D vectors.
- If either one of the vectors is not tridimensional, a :exc:`ValueError` exception is raised.
+ If either one of the vectors is not three-dimensional, a :exc:`ValueError` exception is raised.
.. method:: dot(vector)