py-sympy: updated to 1.9

1.9

Highlights

The internal implementation of Matrix and other matrix classes (SparseMatrix etc) is now DomainMatrix. The ZZ and QQ domains are used for matrices with only integer or rational elements. Otherwise the new EXRAW domain is used. This should be backwards compatible although many internal methods and attributes are changed. At the time of this change the DomainMatrix routines are only used for addition and multiplication of matrices and some other simple low-level operations. Further changes will use DomainMatrix routines for operations like rref, det, lu etc and are expected to lead to big speedups for these computations. At this stage those big speedups are not realised but some basic operations such as indexing a matrix like M[0, 0] could potentially be slower. The new implementation can be much faster for most operations and is expected to lead to significant speed ups over the next few SymPy releases.

Leading term methods now raise PoleError at singularities. There was a long-standing issue of incorrect handling of leading term at singularities, where earlier, for compatibility reasons, the original expression itself was incorrectly returned. exp(1/x).as_leading_term(x) returned exp(1/x), but it does not have any leading term as x->0, so an error must be raised. Note that leadterm used to throw a ValueError even in the previous implementation as the original expression depends on the symbol x. A few examples of functions where this change would be visible - Pow, exp, log, factorial and gamma.

(adam)