#10982: symbolic derivatives should be able to have non-variable arguments
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Reporter: casamayou | Owner:
burcin
Type: defect | Status: new
Priority: minor | Milestone:
sage-5.1
Component: calculus | Resolution:
Keywords: simplify, maxima, symbolic derivative | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Comment (by dsm):
This seems to work for me in 5.0:
{{{
sage: x, y, r, t = var('x, y, r, t')
sage: f = function('f', x, y)
sage: F = f(x = r*cos(t), y = r*sin(t))
sage: d = (diff(F,r,2) + diff(F,t,2)/r**2 + diff(F,r)/r)
sage: d.simplify()
(sin(t)*D[1, 1](f)(r*cos(t), r*sin(t)) + cos(t)*D[0, 1](f)(r*cos(t),
r*sin(t)))*sin(t) + (sin(t)*D[0, 1](f)(r*cos(t), r*sin(t)) + cos(t)*D[0,
0](f)(r*cos(t), r*sin(t)))*cos(t) + (sin(t)*D[1](f)(r*cos(t), r*sin(t)) +
cos(t)*D[0](f)(r*cos(t), r*sin(t)))/r - ((r*sin(t)*D[0, 1](f)(r*cos(t),
r*sin(t)) - r*cos(t)*D[1, 1](f)(r*cos(t), r*sin(t)))*r*cos(t) -
(r*sin(t)*D[0, 0](f)(r*cos(t), r*sin(t)) - r*cos(t)*D[0, 1](f)(r*cos(t),
r*sin(t)))*r*sin(t) + r*sin(t)*D[1](f)(r*cos(t), r*sin(t)) +
r*cos(t)*D[0](f)(r*cos(t), r*sin(t)))/r^2
sage: d.simplify_full()
D[0, 0](f)(r*cos(t), r*sin(t)) + D[1, 1](f)(r*cos(t), r*sin(t))
sage: diff(F,r).simplify()
sin(t)*D[1](f)(r*cos(t), r*sin(t)) + cos(t)*D[0](f)(r*cos(t), r*sin(t))
sage: diff(F,r).simplify_full()
sin(t)*D[1](f)(r*cos(t), r*sin(t)) + cos(t)*D[0](f)(r*cos(t), r*sin(t))
}}}
Although I'm too lazy to bisect to find out when it started working again,
it'd probably be a good idea to add a doctest to make sure that it stays
that way. Not quite sure where to put it, though.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10982#comment:7>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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