Trac #20049: singularity in formula in docstring of SingularityAnalys…

…is-generator

{{{
        .. MATH::

            [z^n] \left(\frac{1}{1-z}\right)^\alpha
            \left(\frac{1}{z} \log \frac{1}{1-z}\right)^\beta
            \left(\frac{1}{z} \log
            \left(\frac{1}{z} \log \frac{1}{1-z}\right)\right)^\delta.
}}}
does not depend on the singularity `\zeta`, which is incorrect (and not
mentioned at all).

URL: http://trac.sagemath.org/20049
Reported by: dkrenn
Ticket author(s): Daniel Krenn
Reviewer(s): Clemens Heuberger

src/sage/rings/asymptotic/asymptotic_expansion_generators.py

@@ -591,10 +591,10 @@ def SingularityAnalysis(var, zeta=1, alpha=0, beta=0, delta=0,
 
         .. MATH::
 
-            [z^n] \left(\frac{1}{1-z}\right)^\alpha
-            \left(\frac{1}{z} \log \frac{1}{1-z}\right)^\beta
-            \left(\frac{1}{z} \log
-            \left(\frac{1}{z} \log \frac{1}{1-z}\right)\right)^\delta.
+            [z^n] \left(\frac{1}{1-z/\zeta}\right)^\alpha
+            \left(\frac{1}{z/\zeta} \log \frac{1}{1-z/\zeta}\right)^\beta
+            \left(\frac{1}{z/\zeta} \log
+            \left(\frac{1}{z/\zeta} \log \frac{1}{1-z/\zeta}\right)\right)^\delta.
 
         INPUT: