Pynac's to_gamma() is buggy

[jdemeyer]

See pynac/pynac#231

On some systems (possibly depending on the linker), this doctest fails:

sage -t src/sage/symbolic/expression.pyx
**********************************************************************
File "src/sage/symbolic/expression.pyx", line 9627, in sage.symbolic.expression.Expression.to_gamma
Failed example:
    binomial(m,n).to_gamma()
Expected:
    gamma(m + 1)/(gamma(m - n + 1)*gamma(n + 1))
Got:
    binomial(m, n)
**********************************************************************

Upstream: Fixed upstream, but not in a stable release.

CC: @rwst

Component: packages: standard

Author: Ralf Stephan

Branch/Commit: 0a73359

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/22421

[jdemeyer]

Description changed:

--- 
+++ 
@@ -1 +1,16 @@
 See https://github.com/pynac/pynac/issues/231
+
+On some systems (possibly depending on the linker), this doctest fails:
+
+```
+sage -t src/sage/symbolic/expression.pyx
+**********************************************************************
+File "src/sage/symbolic/expression.pyx", line 9627, in sage.symbolic.expression.Expression.to_gamma
+Failed example:
+    binomial(m,n).to_gamma()
+Expected:
+    gamma(m + 1)/(gamma(m - n + 1)*gamma(n + 1))
+Got:
+    binomial(m, n)
+**********************************************************************
+```

[jdemeyer]

comment:2

Do you have an idea how much time you need to fix the problems with #22364? Given that #22364 needs work anyway, it makes sense to fix this ticket there (and close this as duplicate). On the other hand, if you don't manage to fix #22364 quickly, we should fix this ticket first because it gives doctest failures.

[jdemeyer]

Changed upstream from Reported upstream. No feedback yet. to Fixed upstream, but not in a stable release.

[rwst]

comment:4

Replying to @jdemeyer:

Do you have an idea how much time you need to fix the problems with #22364? Given that #22364 needs work anyway, it makes sense to fix this ticket there (and close this as duplicate). On the other hand, if you don't manage to fix #22364 quickly, we should fix this ticket first because it gives doctest failures.

No idea about the time because the cause of that is not established with certainty. So, as fixing this the usual way would need a new release that includes #22364 it would be best to not do a release but commit a Pynac patch (containing https://github.com/pynac/pynac/commit/a4dce19f33fc52245f324cb535d24233988dcfa1.diff) with this branch.

[rwst]

Branch: u/rws/pynac_s_to_gamma___is_buggy

[rwst]

Commit: 7cdbdb0

[rwst]

New commits:

7cdbdb0

22421: apply commit from (future) Pynac master

[rwst]

Author: Ralf Stephan

[jdemeyer]

comment:7

Patches are automatically applied now, you should not manually run sage-apply-patches (so you can remove the whole patch() function).

[jdemeyer]

Reviewer: Jeroen Demeyer