Changes between Initial Version and Version 2 of Ticket #8750


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Timestamp:
04/23/10 14:50:48 (12 years ago)
Author:
jhpalmieri
Comment:

Replying to drkirkby:

Two questions:

  • Is sage/finance/time_series.pyx failing on every platform?

This is the only one, and I don't know why. I could try compiling time_series.py with "-std=c99"; maybe that would help?

So is it right to change the test to a more complicated one, just to get the answer we want?

If the difference are for trivial but insurmountable reasons, I don't have an issue with this.

If this comes from python, I find it hard to understand why there should be the difference.

Maybe it comes from math.h somehow?

  • Do we know what an exact (or high numerical precision value) to the answer of the problem in sage/stats/hmm/chmm.pyx is?

This is essentially a new file in the Sage library: in previous versions, it was marked with "nodoctest" at the top of the file. I think that it no longer uses an external library either. So I view this sort of change as working kinks out, and it doesn't bother me.

I'm always a bit reluctant seeing numerical results, with no justification of the answer. The approach taken in these doc tests seems to be: "The answer is X, since I got X on my computer." Then someone gets a different answer on their computer, so the precision of the test is reduced. But rarely do I see much justification for the answer. (An exception has been in some problems like exp(1.0), where the exact answer is known, and we can be sure the problems are numerical rounding issues.

When one reads things like how SQLite (Open Source) is tested

http://sqlite.org/testing.html

or how Wolfram Research claim Mathematica (closed source) is tested

http://reference.wolfram.com/mathematica/tutorial/TestingAndVerification.html

I'm personally left with the feeling the testing in Sage leaves a lot to be desired.

Dave

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  • Ticket #8750

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  • Ticket #8750 – Description

    initial v2  
    1616}}}
    1717then I see {{{-inf}}}.  So I've changed the doctest to use this instead.
     18
     19Oh, and actually reading the docstring, there is an optional argument {{{eps}}} which looks something like an error bound.  By default it's set to 1e-12, and it looks to me like I've added the dots in the 12th place, so now I really don't have any problem with this change.