#11143: Add various Maxima special functions to symbol table
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Reporter: kcrisman | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone:
Component: symbolics | Keywords: ei Ei
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Comment(by kcrisman):
Replying to [comment:1 benjaminfjones]:
> As far as I can tell, the general `exponential_e` function isn't
available directly in Sage or in PARI (which is used to evaluate the
`exponential_integral_1` function in Sage).
That's unfortunate. However,
[http://mpmath.googlecode.com/svn/trunk/doc/build/functions/expintegrals.html#mpmath.expint
mpmath seems to have it]. So we could create a symbolic version and have
the {{{_eval_}}} method call mpmath, which we seem to be moving to.
> Also, it's possible to get maxima to rewrite the exponential integrals
in terms of gamma functions like so:
> {{{
> #!python
> sage: maxima.eval('expintrep:gamma_incomplete')
> 'gamma_incomplete'
> sage: maxima.integrate(exp(-x)*log(x+1), x, 0, oo)
> %e*gamma_incomplete(0,1)
> sage: N(e*gamma(0,1), digits=18)
> 0.596347362323194074
> }}}
Interesting.
> But as you see, `gamma_incomplete` isn't defined in Sage either, but the
table `sage.symbolic.pynac.symbol_table['maxima']` lists the Sage
equivalent `gamma`.
That should be ok; the whole point of the table is to convert into the
Sage equivalent.
>
> By the way, the owner on the ticket is @burcin, does that mean they are
working on it currently?
No, that is an automatic thing that happens. It is possible to be
designated an 'owner' of a ticket in a given component, which basically
means you automatically get updates. If you want to 'own' it, please do!
We really have plenty of special functions in Sage, but they are not
always well exposed at the top level.
Incidentally, once you comment on a ticket, I believe the default is to
copy you in on all replies. So you didn't have to cc: yourself specially
:)
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11143#comment:3>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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