#7423: plot3d can't handle log(0)
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Reporter: kcrisman | Owner: was
Type: defect | Status: new
Priority: major | Milestone: sage-4.2.1
Component: graphics | Keywords:
Work_issues: | Author:
Reviewer: | Merged:
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In 4.2.1.alpha0:
{{{
sage: f(x,y)=ln(x)
sage: P=plot3d(f,(x,0,1),(y,0,1))
sage: P
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', (16, 0))
---------------------------------------------------------------------------
ValueError Traceback (most recent call
last)
<snip a lot>
ValueError: math domain error
}}}
Switch to (x,0.1,1), and all is well. I am pretty sure the problem is
that line 404 in plot/plot3d/parametric_surface.pyx doesn't have an
exception handler for log(0) or other such nan type values:
{{{
sage: math.log(0)
<snip>
ValueError: math domain error
}}}
But in the plotting context, it's silly not to just ignore this; we check
for things like this all the time:
{{{
sage: plot(log,0,1)
<works fine>
}}}
For now it would probably be enough to fix it for the z variable.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7423>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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