Implement extracting symbolic coefficient of rational exponent

[dkrenn]

sage: (x^(1/2)).coefficient(x, 1/3)
sqrt(x)

It seems that 1/3 gets 0 (floor division, whyever).

EDIT: because the function takes an integer:

        INPUT:

        - ``s`` - expression

        - ``n`` - integer, default 1

so it's rather an enhancement.

Reported as pynac/pynac#216

Depends on #23820

Component: symbolics

Author: Ralf Stephan

Branch/Commit: 6d8d994

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/19996

[rwst]

Upstream: Reported upstream. Developers acknowledge bug.

[rwst]

Description changed:

--- 
+++ 
@@ -5,3 +5,4 @@
 ```
 It seems that `1/3` gets `0` (floor division, whyever).
 
+Reported as https://github.com/pynac/pynac/issues/216

[rwst]

Description changed:

--- 
+++ 
@@ -5,4 +5,15 @@
 ```
 It seems that `1/3` gets `0` (floor division, whyever).
 
+EDIT: because the function takes an integer:
+
+```
+        INPUT:
+
+        - ``s`` - expression
+
+        - ``n`` - integer, default 1
+```
+so it's rather an enhancement.
+
 Reported as https://github.com/pynac/pynac/issues/216

[rwst]

Changed upstream from Reported upstream. Developers acknowledge bug. to Reported upstream. Developers deny it's a bug.

[rwst]

Branch: u/rws/implement_extracting_symbolic_coefficient_of_rational_exponent

[rwst]

Changed upstream from Reported upstream. Developers deny it's a bug. to Fixed upstream, in a later stable release.

[rwst]

comment:4

This branch needs pynac-0.7.11+ and allows any coefficient. There is different behaviour in this doctest:

             sage: f = (a*sqrt(2))*x^2 + sin(y)*x^(1/2) + z^z
...
             sage: f.coefficient(x, 0)
-            sqrt(x)*sin(y) + z^z
+            z^z

---

New commits:

484142a

19996: allow any n in ex.coefficient(x,n)

[rwst]

Author: Ralf Stephan