#13246: Automatic exclusion of non-domain points in things like arcsec
-----------------------------------------+--------------------------
Reporter: kcrisman | Owner: jason, was
Type: defect | Status: needs_work
Priority: major | Milestone: sage-6.3
Component: graphics | Resolution:
Keywords: | Merged in:
Authors: Punarbasu Purkayastha | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
-----------------------------------------+--------------------------
Changes (by ppurka):
* cc: vbraun (added)
Comment:
What do you make of this? Bug in cython? cc: vbraun
{{{
sage: from sage.plot.misc import setup_for_eval_on_grid
sage: f, d = setup_for_eval_on_grid(arcsec, [(-2, 2)])
sage: f(-0.992725195401)
---------------------------------------------------------------------------
AttributeError Traceback (most recent call
last)
<ipython-input-3-a06f3eb7afeb> in <module>()
----> 1 f(-RealNumber('0.992725195401'))
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/ext/interpreters/wrapper_rdf.so in
sage.ext.interpreters.wrapper_rdf.Wrapper_rdf.__call__
(sage/ext/interpreters/wrapper_rdf.c:1689)()
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/symbolic/function.so in
sage.symbolic.function.BuiltinFunction.__call__
(sage/symbolic/function.cpp:9088)()
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/symbolic/expression.so in
sage.symbolic.expression.Expression.__complex__
(sage/symbolic/expression.cpp:8174)()
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/symbolic/expression.so in
sage.symbolic.expression.Expression._eval_self
(sage/symbolic/expression.cpp:6973)()
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/functions/trig.pyc in _evalf_(self, x, parent, algorithm)
732 if parent is float:
733 return math.acos(1/x)
--> 734 return (1/x).arccos()
735
736 def _eval_numpy_(self, x):
AttributeError: 'complex' object has no attribute 'arccos'
sage:
Exiting Sage (CPU time 0m0.25s, Wall time 0m12.78s).
basu@plantain:~/Installations/sage [test-float] $ git diff develop |cat #
insert a print statement
diff --git a/src/sage/symbolic/function.pyx
b/src/sage/symbolic/function.pyx
index eed56e6..75c723d 100644
--- a/src/sage/symbolic/function.pyx
+++ b/src/sage/symbolic/function.pyx
@@ -934,6 +934,7 @@ cdef class BuiltinFunction(Function):
# conversion to the original parent failed
# we try if it works with the corresponding complex domain
if org_parent is float:
+ print "DEBUG: it is float - {}".format(float(res))
try:
return complex(res)
except (TypeError, ValueError):
basu@plantain:~/Installations/sage [test-float] $ ./sage -b >& /dev/null ;
./sage
┌────────────────────────────────────────────────────────────────────┐
│ Sage Version 6.3.beta2, Release Date: 2014-05-24 │
│ Type "notebook()" for the browser-based notebook interface. │
│ Type "help()" for help. │
└────────────────────────────────────────────────────────────────────┘
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ Warning: this is a prerelease version, and it may be unstable. ┃
┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
sage: from sage.plot.misc import setup_for_eval_on_grid
sage: f, d = setup_for_eval_on_grid(arcsec, [(-2, 2)])
sage: f(-0.992725195401)
---------------------------------------------------------------------------
ValueError Traceback (most recent call
last)
<ipython-input-3-a06f3eb7afeb> in <module>()
----> 1 f(-RealNumber('0.992725195401'))
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/ext/interpreters/wrapper_rdf.so in
sage.ext.interpreters.wrapper_rdf.Wrapper_rdf.__call__
(sage/ext/interpreters/wrapper_rdf.c:1689)()
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/symbolic/function.so in
sage.symbolic.function.BuiltinFunction.__call__
(sage/symbolic/function.cpp:9099)()
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/symbolic/expression.so in
sage.symbolic.expression.Expression.__float__
(sage/symbolic/expression.cpp:8022)()
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/symbolic/expression.so in
sage.symbolic.expression.Expression._eval_self
(sage/symbolic/expression.cpp:6973)()
/home/basu/Installations/sage/local/lib/python2.7/site-
packages/sage/functions/trig.pyc in _evalf_(self, x, parent, algorithm)
731 """
732 if parent is float:
--> 733 return math.acos(1/x)
734 return (1/x).arccos()
735
ValueError: math domain error
sage:
}}}
The error changes to `ValueError` from `AttributeError`. How can a print
statement change the call sequence?
--
Ticket URL: <http://trac.sagemath.org/ticket/13246#comment:28>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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