#9424: numerical evaluation of symbolic sums
-------------------------+--------------------------------------------------
Reporter: burcin | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-4.5
Component: symbolics | Keywords:
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Symbolics sums returned from maxima cannot be numerically evaluated, since
they don't define an `_evalf_()` method.
This was reported by dirkd on sage-support:
{{{
Why is evaluating this expression problematical?
y1(x)=x^2;y2(x)=5-x;
a0=1;an=3;Delta=(an-a0)/n;p(k)=a0+(k-1/2)*Delta;
I(n)=sum(abs(y2(p(k))-y1(p(k)))*Delta,k,1,n);
N(I(10))
SAGE respons:
<snipped traceback>
File "expression.pyx", line 3797, in
sage.symbolic.expression.Expression.n (sage/symbolic/expression.cpp:
17022)
TypeError: cannot evaluate symbolic expression numerically
}}}
Here is the thread:
http://groups.google.com/group/sage-support/t/615b15ca638c9652
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9424>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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