#10042: Doctest failure in sage/rings/polynomial/polynomial_element.pyx
------------------------------+---------------------------------------------
Reporter: mpatel | Owner: mvngu
Type: defect | Status: positive_review
Priority: blocker | Milestone: sage-4.6
Component: doctest | Keywords:
Author: Dima Pasechnik | Upstream: N/A
Reviewer: Leif Leonhardy | Merged:
Work_issues: |
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Comment(by drkirkby):
Replying to [comment:77 leif]:
> In the light of the "user warning" given, I think using dots is
acceptable here.
Yes, agreed. Just in general I think this method of comparing floating
point numbers is rather dumb.
> W.r.t. 387 vs. SSE, try this:
=== SSE ===
{{{
drkir...@hawk:~$ gcc test3.c -lm -mfpmath=sse
drkir...@hawk:~$ ./a.out
float:
+1.7724539041519165039062500000000000000000000000000000000000000000000000
-1.7724539041519165039062500000000000000000000000000000000000000000000000
double:
+1.7724538509055158819194275565678253769874572753906250000000000000000000
-1.7724538509055158819194275565678253769874572753906250000000000000000000
long double:
+1.7724538509055159927248895845863785325491335242986679077148437500000000
-1.7724538509055159927248895845863785325491335242986679077148437500000000
}}}
=== 387 ===
{{{
drkir...@hawk:~$ gcc test3.c -lm -mfpmath=387
drkir...@hawk:~$ ./a.out
float:
+1.7724539041519165039062500000000000000000000000000000000000000000000000
-1.7724538755670267153874419818748719990253448486328125000000000000000000
double:
+1.7724538509055158819194275565678253769874572753906250000000000000000000
-1.7724538509055158819194275565678253769874572753906250000000000000000000
long double:
+1.7724538509055159927248895845863785325491335242986679077148437500000000
-1.7724538509055159927248895845863785325491335242986679077148437500000000
}}}
> I only get a different result for the negated square root in the float
case with 387 code (Core2, gcc 4.4.3).
Yes, I too get different results (!OpenSolaris, Intel Xeon W3580 @ 3.33
GHz, gcc 4.5.0)
Perhaps Paul has some comments on those different numbers. They would
appear to violate one of the principle claims of IEE-754 to me, but
perhaps I am wrong.
Dave
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10042#comment:78>
Sage <http://www.sagemath.org>
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