#11948: Fix numeric evaluation of error function
-------------------------+--------------------------------------------------
Reporter: jdemeyer | Owner: jason, jkantor
Type: defect | Status: new
Priority: major | Milestone: sage-pending
Component: numerical | Keywords: erf erfc
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies: #11130
-------------------------+--------------------------------------------------
Because the argument is converted to `float` first, the error function
`erf()` cannot numerically be evaluated for complex arguments:
{{{
sage: erf(pi - 1/2*I).n()
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', (1108, 0))
---------------------------------------------------------------------------
TypeError Traceback (most recent call
last)
/usr/local/src/sage-4.7.2.alpha2/<ipython console> in <module>()
/usr/local/src/sage-4.7.2.alpha2/local/lib/python2.6/site-
packages/sage/symbolic/expression.so in
sage.symbolic.expression.Expression._numerical_approx
(sage/symbolic/expression.cpp:17793)()
/usr/local/src/sage-4.7.2.alpha2/local/lib/python2.6/site-
packages/sage/symbolic/expression.so in
sage.symbolic.expression.Expression._convert
(sage/symbolic/expression.cpp:5004)()
/usr/local/src/sage-4.7.2.alpha2/local/lib/python2.6/site-
packages/sage/functions/other.pyc in _evalf_(self, x, parent)
79 if prec > 53:
80 raise NotImplementedError, "erf not implemented for
precision higher than 53"
---> 81 return parent(1 - pari(float(x)).erfc())
82
83 def _derivative_(self, x, diff_param=None):
/usr/local/src/sage-4.7.2.alpha2/local/lib/python2.6/site-
packages/sage/rings/complex_number.so in
sage.rings.complex_number.ComplexNumber.__float__
(sage/rings/complex_number.c:7233)()
TypeError: Unable to convert 3.14159265358979 - 0.500000000000000*I to
float; use abs() or real_part() as desired
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11948>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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