Numerical noise in devel/sage/sage/symbolic/constants_c.pyx

[sagetrac-drkirkby]

== The computer hardware & software ==

• Sun Blade 1000
• 2 x 900 MHz UltraSPARC III+ CPUs
• 2 GB RAM
• Solaris 10 03/2005 - the first release of Solaris 10.

== The Sage software ==
Sage 4.3.3 with various patches to get it to compile on Solaris. (The notebook is not working properly though).

== The test failures ==

**********************************************************************
File "/export/home/drkirkby/sage-4.3.3/devel/sage/sage/symbolic/constants_c.pyx", line 195:
    sage: float(e)
Expected:
    2.7182818284590451
Got:
    2.7182818284590455
**********************************************************************
File "/export/home/drkirkby/sage-4.3.3/devel/sage/sage/symbolic/constants_c.pyx", line 197:
    sage: e.__float__()
Expected:
    2.7182818284590451
Got:
    2.7182818284590455
**********************************************************************

This failure on SPARC when displaying E has been seen before.

Component: porting: Solaris

Author: David Kirkby

Reviewer: Mitesh Patel, Jaap Spies

Merged: sage-4.3.4.alpha1

Issue created by migration from https://trac.sagemath.org/ticket/8374

[sagetrac-drkirkby]

comment:2

The attached patch fixes these two failures.

kirkby@redstart:~/sage-4.3.3$ ./sage -t devel/sage/sage/symbolic/constants_c.p
sage -t  "devel/sage/sage/symbolic/constants_c.pyx"
         [65.4 s]

----------------------------------------------------------------------
All tests passed!
Total time for all tests: 65.4 seconds
drkirkby@redstart:~/sage-4.3.3$
yxkirkby@redstart:~/sage-4.3.3$ ./sage -t devel/sage/sage/symbolic/constants_c.py
sage -t  "devel/sage/sage/symbolic/constants_c.pyx"
         [77.5 s]

----------------------------------------------------------------------
All tests passed!
Total time for all tests: 77.5 seconds

An optional test, which currently expoects the same value of e has also been changed.

The patch, which will be attached shortly, also has some notes showing

• A high precision value of e
• The IEEE 754 value
• The correctly rounded result
• The value given on a Sun Blade 1000 with SPARC processors.

Dave

[sagetrac-drkirkby]

Mercurial patch

[sagetrac-drkirkby]

comment:3

Attachment: 8374-numerical-noise.patch.gz

[sagetrac-drkirkby]

Author: David Kirkby

[qed777]

comment:4

I've left a review comment at #8375.

[qed777]

Reviewer: Mitesh Patel

[sagetrac-drkirkby]

Attachment: 8374-numerical-noise.2.patch.gz

[sagetrac-drkirkby]

comment:5

I've addressed the spelling & grammar errors in 8374-numerical-noise.2.patch I forgot to overwrite the old one, so there is now a second patch.

See also comments at #8375

[jaapspies]

comment:6

Replying to @sagetrac-drkirkby:

I've addressed the spelling & grammar errors in 8374-numerical-noise.2.patch I forgot to overwrite the old one, so there is now a second patch.

See also comments at #8375

So a positive review.

Jaap

[jaapspies]

Changed reviewer from Mitesh Patel to Mitesh Patel, Jaap Spies

[mwhansen]

Merged: sage-4.3.4.alpha1