#11888: Sage is missing the lambert_w function
----------------------------------------------------------------------------------+
Reporter: benjaminfjones
| Owner: burcin
Type: defect
| Status: needs_work
Priority: minor
| Milestone: sage-5.0
Component: symbolics
| Keywords: lambert_w symbolics conversion maxima sd35.5
Work_issues:
| Upstream: N/A
Reviewer: Keshav Kini, Karl-Dieter Crisman, Fredrik Johansson, Burcin
Erocal | Author: Benjamin Jones
Merged:
| Dependencies: #12507
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Changes (by benjaminfjones):
* dependencies: #9130 => #12507
Comment:
I've written a new patch that includes significant changes compared to the
last one. I think I've included all of burcin's suggestions and I think
it's much improved now. All tests pass with the patch applied on 5.0.beta4
+ #12507.
One thing I haven't managed to figure out is how to get integration to
work, e.g.
{{{
sage: integrate(lambert_w(x), x)
...
RuntimeError: ECL says: Error executing code in Maxima: lambert_w: wrong
number of arguments.
}}}
I guess that's because there isn't a two-argument version of lambert_w
defined in maxima. The conversion maxima -> Sage works (as shown in one of
the doctests) but it looks like the other way doesn't. Another example:
{{{
sage: maxima(lambert_w(5))
Maxima ERROR:
lambert_w: wrong number of arguments.
-- an error. To debug this try: debugmode(true);
}}}
Q: How do I get around this?
Numerical integration also fails unless I pass a lambda function:
{{{
sage: numerical_integral(lambert_w(x), 0, 1)
Exception TypeError: "function not supported for these types, and can't
coerce safely to supported types" in 'sage.gsl.integration.c_ff' ignored
...
(0.0, 0.0)
}}}
but ....
{{{
sage: numerical_integral(lambda x: lambert_w(x), 0, 1)
(0.33036612476168054, 3.667800782666048e-15)
}}}
Q: How do I fix this?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11888#comment:31>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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