Make log gamma symbolic

[kcrisman]

Currently, there is no way to send log_gamma to Maxima, for instance. This can be fixed by following the models in the functions/ directory; it should be possible to make it a GinacFunction. Before doing so, though, one will have to resolve #10072, since the evaluation will be wrong (?) otherwise.

Apply only attachment: trac_10075.patch.

Depends on #12507
Depends on #9130

CC: @sagetrac-ktkohl @benjaminfjones

Component: symbolics

Keywords: sd35.5

Author: Karen Kohl, Karl-Dieter Crisman

Reviewer: Karl-Dieter Crisman, Benjamin Jones

Merged: sage-5.0.beta7

Issue created by migration from https://trac.sagemath.org/ticket/10075

[sagetrac-ktkohl]

Changed keywords from none to sd35.5

[sagetrac-ktkohl]

comment:3

Sage gives this error message on startup:

ValueError: cannot find GiNaC function with name lgamma and 1 arguments

with this change in functions/other.py:

class Function_log_gamma(GinacFunction):

  def __init__(self):
    GinacFunction.__init__(self, "log_gamma", latex_name=r'\log\Gamma',
      ginac_name='lgamma', conversions={'mathematica':'LogGamma','maxima':'log_gamma'})

[kcrisman]

comment:4

More precisely,

class Function_log_gamma(GinacFunction):
    def __init__(self):
        GinacFunction.__init__(self, "log_gamma", latex_name=r'\log\Gamma',
          ginac_name='lgamma', conversions={'mathematica':'LogGamma','maxima':'log_gamma'})

log_gamma = Function_log_gamma()

causes this failure.

[burcin]

comment:5

It works if you drop the ginac_name argument. The function is named log_gamma in pynac.

[kcrisman]

comment:6

Weird. So what about things like

unsigned lgamma_serial "GiNaC::lgamma_SERIAL::serial" # logarithm of gamma function

?

[sagetrac-ktkohl]

Attachment: trac_10075_log_gamma.patch.gz

symbolic log_gamma (with modification of functions.rst in case merged before #9130)

[sagetrac-ktkohl]

symbolic log_gamma (with modification of functions.rst in case merged after #9130)

[sagetrac-ktkohl]

Author: Karen T. Kohl