#11143: define symbolic functions for exponential integrals
--------------------------------------------------+-------------------------
Reporter: kcrisman | Owner:
benjaminfjones
Type: defect | Status: new
Priority: major | Milestone: sage-4.7.2
Component: symbolics | Keywords: ei Ei
special function maxima sd32
Work_issues: | Upstream: N/A
Reviewer: Burcin Erocal, Karl-Dieter Crisman | Author: Benjamin
Jones
Merged: | Dependencies: #11513
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Comment(by benjaminfjones):
Trying to finish up the patch, I've run into a problem evaluating any of
my new functions at python floats. For example, apply the patch and try:
{{{
sage: exp_integral_e1(float(1))
ERROR: An unexpected error occurred while tokenizing input
The following traceback may be corrupted or invalid
The error message is: ('EOF in multi-line statement', (690, 0))
---------------------------------------------------------------------------
AttributeError Traceback (most recent call
last)
/Users/jonesbe/sage/sage-4.7.2.alpha2/devel/sage-test/sage/<ipython
console> in <module>()
/Users/jonesbe/sage/latest/local/lib/python2.6/site-
packages/sage/symbolic/function.so in
sage.symbolic.function.Function.__call__
(sage/symbolic/function.cpp:4599)()
/Users/jonesbe/sage/latest/local/lib/python2.6/site-
packages/sage/functions/exp_integral.pyc in _eval_(self, z)
335 """
336 if not isinstance(z, Expression) and is_inexact(z):
--> 337 return self._evalf_(z, parent(z))
338
339 return None # leaves the expression unevaluated
/Users/jonesbe/sage/latest/local/lib/python2.6/site-
packages/sage/functions/exp_integral.pyc in _evalf_(self, z, parent)
350 """
351 import mpmath
--> 352 return mpmath_utils.call(mpmath.e1, z, parent=parent)
353
354 def _derivative_(self, z, diff_param=None):
/Users/jonesbe/sage/latest/local/lib/python2.6/site-
packages/sage/libs/mpmath/utils.so in sage.libs.mpmath.utils.call
(sage/libs/mpmath/utils.c:5277)()
AttributeError: type object 'float' has no attribute 'prec'
}}}
You also get the error if you try to plot any of the exponential integral
functions as they are written unless you wrap the input with `RDF` or
something similar.
The error is being raised inside the `call` function in
`sage/libs/mpmath/util.pyx`. I've looked through that code and thought
about what would happen if the `prec` option is not specified (as in my
code) and the parent is `None` (as when a python float is passed), but I
can't figure out why it doesn't work to pass a float.
On the other hand, changing the lines in the `_evalf` method
{{{
import mpmath
return mpmath_utils.call(mpmath.e1, z, parent=parent)
}}}
to
{{{
import mpmath
if isinstance(parent, Parent) and hasattr(parent, 'prec'):
prec = parent.prec()
else:
prec = 53
return mpmath_utils.call(mpmath.si, z, prec=prec)
}}}
fixes the error.
What do people think? Is this a bug in the `call` function (which claims
it will accept any type that mpmath handles natively like python floats)
or is there something wrong with my code?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11143#comment:24>
Sage <http://www.sagemath.org>
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