Changes between Initial Version and Version 2 of Ticket #10050


Ignore:
Timestamp:
01/03/12 15:33:28 (9 years ago)
Author:
burcin
Comment:

Replying to zimmerma:

note that there are issues with the current polylog function:

sage: polylog(2,1.0)
1/6*pi^2
sage: polylog(2,0.9)
polylog(2, 0.900000000000000)

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 bessel_J(2,0.9).

Should I open a separate ticket?

I was thinking of the other polylog like functions from ginac/inifcns_nstdsums.cpp 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.

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  • Ticket #10050

    • Property Keywords beginner removed
    • Property Summary changed from wrap the polylogarithm functions from pynac to numeric evaluation of polylog
  • Ticket #10050 – Description

    initial v2  
    1 Ginac includes an implementation of polylogarithms. The numeric methods of this implementation is commented out in the pynac source since it tries to call the `CLN` library directly, but the other parts should work.
     1Numeric evaluation methods for the `polylog` function are commented out in the pynac source since it tries to call the `CLN` library directly. The calls to CLN should be replaced with their MPFR, etc. equivalents.
    22
    3 We should expose these functions (with a name other than `Li`).
     3{{{
     4sage: polylog(2,1.0)
     51/6*pi^2
     6sage: polylog(2,0.9)
     7polylog(2, 0.900000000000000)
     8}}}
    49
    5 An example of how this can be done is available in #8864.
     10This is also [https://bitbucket.org/burcin/pynac/issue/3/ pynac issue #3]