can not simplify derivative of erf #8568
Description
Sometimes sage can differentiate erf, but if there are two variables involved it gets confused in simplification and passes too many arguments to erf in maxima.
----------------------------------------------------------------------
| Sage Version 4.3.3, Release Date: 2010-02-21 |
| Type notebook() for the GUI, and license() for information. |
----------------------------------------------------------------------
sage: var('c x')
(c, x)
sage: diff(erf(x), x)
D[0](erf)(x)
sage: simplify(diff(erf(x), x))
2*e^(-x^2)/sqrt(pi)
sage: diff(erf(c * x), x)
c*D[0](erf)(c*x)
sage: simplify(diff(erf(c * x), x))
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
/.../<ipython console> in <module>()
/.../sage-4.3.3-linux-64bit-ubuntu_9.10-x86_64-Linux/local/lib/python2.6/site-packages/sage/calculus/functional.pyc
in simplify(f)
49 """
50 try:
---> 51 return f.simplify()
52 except AttributeError:
53 return f
/.../sage-4.3.3-linux-64bit-ubuntu_9.10-x86_64-Linux/local/lib/python2.6/site-packages/sage/symbolic/expression.so
in sage.symbolic.expression.Expression.simplify (sage/symbolic/expression.cpp:21495)()
/.../sage-4.3.3-linux-64bit-ubuntu_9.10-x86_64-Linux/local/lib/python2.6/site-packages/sage/symbolic/expression.so
in sage.symbolic.expression.Expression._maxima_ (sage/symbolic/expression.cpp:3435)()
/.../sage-4.3.3-linux-64bit-ubuntu_9.10-x86_64-Linux/local/lib/python2.6/site-packages/sage/structure/sage_object.so
in sage.structure.sage_object.SageObject._interface_ (sage/structure/sage_object.c:3501)()
/.../sage-4.3.3-linux-64bit-ubuntu_9.10-x86_64-Linux/local/lib/python2.6/site-packages/sage/interfaces/expect.pyc
in __call__(self, x, name)
1030
1031 if isinstance(x, basestring):
-> 1032 return cls(self, x, name=name)
1033 try:
1034 return self._coerce_from_special_method(x)
/.../sage-4.3.3-linux-64bit-ubuntu_9.10-x86_64-Linux/local/lib/python2.6/site-packages/sage/interfaces/expect.pyc
in __init__(self, parent, value, is_name, name)
1449 except (TypeError, KeyboardInterrupt, RuntimeError, ValueError), x:
1450 self._session_number = -1
-> 1451 raise TypeError, x
1452 self._session_number = parent._session_number
1453
TypeError: Error executing code in Maxima
CODE:
sage4 : (c)*(diff('erf(c, x), c, 1))$
Maxima ERROR:
Wrong number of arguments to erf
-- an error. To debug this try: debugmode(true);
CC: @jasongrout @burcin
Component: calculus
Author: Burcin Erocal, Karl-Dieter Crisman
Reviewer: Karl-Dieter Crisman, Burcin Erocal
Merged: sage-4.6.alpha2
Issue created by migration from https://trac.sagemath.org/ticket/8568