Sage: Ticket #10050: implement Nielsen Generalized Polylogarithm
https://trac.sagemath.org/ticket/10050
<p>
Numeric evaluation methods for the Nielsen Generalized Polylogarithm are commented out in the pynac source since it tries to call the <code>CLN</code> library directly. The calls to CLN should be replaced with their MPFR, etc. equivalents and the function made available symbolically in Sage. The Pynac part is <a class="ext-link" href="https://github.com/pynac/pynac/issues/3"><span class="icon"></span>https://github.com/pynac/pynac/issues/3</a>
</p>
en-usSagehttps://trac.sagemath.org/chrome/site/logo_sagemath_trac.png
https://trac.sagemath.org/ticket/10050
Trac 1.1.6zimmermaWed, 21 Dec 2011 08:55:03 GMT
https://trac.sagemath.org/ticket/10050#comment:1
https://trac.sagemath.org/ticket/10050#comment:1
<p>
note that there are issues with the current polylog function:
</p>
<pre class="wiki">sage: polylog(2,1.0)
1/6*pi^2
sage: polylog(2,0.9)
polylog(2, 0.900000000000000)
</pre><p>
The first command should not evaluate symbolically, since the input 1.0 is a floating-point.
The second command should evaluate numerically, like for example <code>bessel_J(2,0.9)</code>.
</p>
<p>
Should I open a separate ticket?
</p>
<p>
Paul
</p>
TicketburcinTue, 03 Jan 2012 15:33:28 GMTdescription, summary changed; keywords deleted
https://trac.sagemath.org/ticket/10050#comment:2
https://trac.sagemath.org/ticket/10050#comment:2
<ul>
<li><strong>keywords</strong>
<em>beginner</em> removed
</li>
<li><strong>description</strong>
modified (<a href="/ticket/10050?action=diff&version=2">diff</a>)
</li>
<li><strong>summary</strong>
changed from <em>wrap the polylogarithm functions from pynac</em> to <em>numeric evaluation of polylog</em>
</li>
</ul>
<p>
Replying to <a class="ticket" href="https://trac.sagemath.org/ticket/10050#comment:1" title="Comment 1">zimmerma</a>:
</p>
<blockquote class="citation">
<p>
note that there are issues with the current polylog function:
</p>
<pre class="wiki">sage: polylog(2,1.0)
1/6*pi^2
sage: polylog(2,0.9)
polylog(2, 0.900000000000000)
</pre><p>
The first command should not evaluate symbolically, since the input 1.0 is a floating-point.
The second command should evaluate numerically, like for example <code>bessel_J(2,0.9)</code>.
</p>
<p>
Should I open a separate ticket?
</p>
</blockquote>
<p>
I was thinking of the other polylog like functions from <a class="ext-link" href="https://bitbucket.org/burcin/pynac/src/tip/ginac/inifcns_nstdsums.cpp"><span class="icon"></span>ginac/inifcns_nstdsums.cpp</a> when I created this ticket. It seems even the symbolic evaluation code for these is commented out, so this would require quite a bit more work than I thought. I am removing the beginner keyword and changing this ticket to only mention numeric evaluation of polylogs.
</p>
TicketrwsSat, 26 Jul 2014 13:08:53 GMTdescription changed
https://trac.sagemath.org/ticket/10050#comment:3
https://trac.sagemath.org/ticket/10050#comment:3
<ul>
<li><strong>description</strong>
modified (<a href="/ticket/10050?action=diff&version=3">diff</a>)
</li>
</ul>
TicketrwsSat, 09 May 2015 07:26:14 GMTmilestone changed
https://trac.sagemath.org/ticket/10050#comment:4
https://trac.sagemath.org/ticket/10050#comment:4
<ul>
<li><strong>milestone</strong>
changed from <em>sage-wishlist</em> to <em>sage-duplicate/invalid/wontfix</em>
</li>
</ul>
<p>
At the moment Pynac calls <code>symbolic/pynac.pyx:py_li()</code> which calls <code>mpmath</code>. It is not clear to me why the outcommented pynac code would be needed, to remove the call overhead? If you replace the CLN dependency, with what MPFR?, how would this be better or faster than mpmath?
</p>
<p>
Proposed to be invalid. If you agree I would reword this ticket to fix the mentioned bugs only.
</p>
TicketrwsSat, 09 May 2015 08:43:14 GMTsummary, description, milestone changed
https://trac.sagemath.org/ticket/10050#comment:5
https://trac.sagemath.org/ticket/10050#comment:5
<ul>
<li><strong>summary</strong>
changed from <em>numeric evaluation of polylog</em> to <em>implement Nielsen Generalized Polylogarithm</em>
</li>
<li><strong>description</strong>
modified (<a href="/ticket/10050?action=diff&version=5">diff</a>)
</li>
<li><strong>milestone</strong>
changed from <em>sage-duplicate/invalid/wontfix</em> to <em>sage-wishlist</em>
</li>
</ul>
<p>
Ah okay, what was meant in this ticket's description is GiNaC's implementation of the Nielsen Generalized Polylogarithm which is not in mpmath. I have changed the description accordingly.
</p>
TicketrwsSat, 09 May 2015 08:52:11 GMT
https://trac.sagemath.org/ticket/10050#comment:6
https://trac.sagemath.org/ticket/10050#comment:6
<p>
Replying to <a class="ticket" href="https://trac.sagemath.org/ticket/10050#comment:1" title="Comment 1">zimmerma</a>:
</p>
<blockquote class="citation">
<p>
note that there are issues with the current polylog function:
</p>
<pre class="wiki">sage: polylog(2,1.0)
1/6*pi^2
sage: polylog(2,0.9)
polylog(2, 0.900000000000000)
</pre><p>
The first command should not evaluate symbolically, since the input 1.0 is a floating-point.
The second command should evaluate numerically, like for example <code>bessel_J(2,0.9)</code>.
</p>
<p>
Should I open a separate ticket?
</p>
</blockquote>
<p>
Better late than never. This is now <a class="closed ticket" href="https://trac.sagemath.org/ticket/18386" title="defect: Doctests for: fix polylog evalf (closed: fixed)">#18386</a>.
</p>
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