#11126: Symbolic Ring is_integral_domain() throws exception
-------------------------+--------------------------------------------------
Reporter: duenez | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-4.7
Component: symbolics | Keywords: symbolics matrix
Author: duenez | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
-------------------------+--------------------------------------------------
The symbolic ring (SR) in sage is considered a field:
{{{
sage: SR.is_field()
True
}}}
but it is not considered an integer domain:
{{{
sage: SR.is_integer_domain()
NotImplementedError Traceback (most recent call
last)
/***/sage-4.6.2-linux-32bit-
ubuntu_10.04_lts-i686-Linux-i686-Linux/<ipython console> in <module>()
/***/sage-4.6.2-linux-32bit-
ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-
packages/sage/matrix/matrix2.so in sage.matrix.matrix2.Matrix.solve_right
(sage/matrix/matrix2.c:3387)()
/***/sage-4.6.2-linux-32bit-
ubuntu_10.04_lts-i686-Linux-i686-Linux/local/lib/python2.6/site-
packages/sage/rings/ring.so in sage.rings.ring.Ring.is_integral_domain
(sage/rings/ring.c:6035)()
NotImplementedError:
}}}
However, functions like matrix's '''solve_right()''' (correctly) test for
the ring being integral domain before testing for the ring being a field.
Thus, matrices with symbolic entries fail with an exception when trying to
use '''solve_right()''' and related functions.
This behavior was introduced by ticket #10481 where they (correctly)
changed the behavior of '''is_integral_domain() '''of a ring to raise an
exception instead of returning it.
The problems is that '''SR''' does not override '''is_integral_domain()
'''correctly. I propose the addition of the following function to
sage/symbolic/rings.pyx
{{{
#!python
def is_integral_domain(self, proof = True):
"""
Returns True, since the symbolic expression ring is reported as a
field.
EXAMPLES::
sage: SR.is_integral_domain()
True
"""
return True
}}}
What do you think?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11126>
Sage <http://www.sagemath.org>
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