#13271: wrong sign with function Ei and limit
---------------------------------+------------------------------------------
Reporter: dkrenn | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-5.3
Component: symbolics | Resolution:
Keywords: Ei limit sign | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
---------------------------------+------------------------------------------
Changes (by kcrisman):
* cc: nbruin (added)
Comment:
Just as a data point, we still get this after #11143, unsurprisingly given
that that doesn't touch Maxima.
This is a little weird, since in both Maxima in current Sage and in Maxima
5.27
{{{
(%i5) limit(expintegral_ei(-z),z,inf);
(%o5) 0
}}}
Further,
{{{
sage: A = Ei(-Z)._maxima_()
sage: A.limit(Z,'inf')
0
}}}
Using the Maxima lib version is ok too.
I have a feeling that the following is the problem,
{{{
sage: sage.interfaces.maxima_lib.sr_to_max(SR(Ei(-Z)))
<ECL: ((%GAMMA_INCOMPLETE) 0 ((MTIMES) |$z| -1))>
}}}
combined with
{{{
(%i1) limit(gamma_incomplete(0,-Z),Z,inf);
(%o1) infinity
}}}
So somehow this is completely bypassing the symbol table. I am out of my
depth in our ECL conversions...
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13271#comment:1>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
