[Numpy-discussion] Four bugs in Numexpr and another repository
David M. Cooke
cookedm@physics.mcmaster...
Thu Apr 19 15:03:45 CDT 2007
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Ivan Vilata i Balaguer wrote:
> Hi all,
>
> Francesc and I have found four bugs in Numexpr while developing
> PyTables. To spare you from the gory details, I'll point you to the
> PyTables Trac instance, where bugs are commented and patches are
> available which should be more or less readily applicable to mainstream
> Numexpr:
>
> 1. VariableNode error when numexpr is asked to evaluate some functions
> (arc*, pow): http://www.pytables.org/trac/ticket/54
>
> >>> numexpr.evaluate('arcsin(0.5)')
> Traceback (most recent call last):
> ...
> TypeError: 'VariableNode' object is not callable
Looks like an oversight. Fixed in svn (r2934).
>
> 2. 'int' object has no attribute '__gt__' error in tables.numexpr (also
> affects to original numexpr): http://www.pytables.org/trac/ticket/55
>
> >>> numexpr.evaluate('cos(1.3) < 0')
> Traceback (most recent call last):
> ...
> AttributeError: 'int' object has no attribute '__gt__'
Fixed, r2935.
> 3. Wrong behaviour of where function of numexpr (als affects to original
> numexpr): http://www.pytables.org/trac/ticket/56
>
> >>> a = numpy.arange(0,5)
> >>> numexpr.evaluate('where(a < 2, 1, 0)')
> Traceback (most recent call last):
> ...
> NotImplementedError: couldn't find matching opcode for 'where_bbbb'
Got to stare at this one. Support for True and False might be the best
thing here, so that the above is where_biii.
> 4. Segmentation fault with string constant expression:
> http://www.pytables.org/trac/ticket/58
>
> >>> tables.numexpr.evaluate('"foo"')
> Segmentation fault (core dumped)
>
> This in fact only applies to the PyTables version of Numexpr, which
> includes the patches I've been sending here for a while. I'm taking
> this opportunity to point out that you can check that version out
> from the PyTables Subversion repository:
> http://www.pytables.org/svn/pytables/trunk/tables/numexpr/
>
> If you need more help on this, don't hesitate to ask. Thanks a lot!
> (Is it OK to report Numexpr bugs in the SciPy Trac instance? And,
> what's the right capitalisation of "Numexpr"? ;) )
Yes; open a bug for #3 on the SciPy Trac, and assign them to me
(cookedm), so I don't forget about them. You can open a bug for adding
string expressions, so at least people can find it if they want. I'm
still not convinced of its usefulness (compared with the added complexity).
Looks like I use either numexpr or Numexpr for capitialisation (NumExpr
on the SciPy wiki, but that's just wikification).
- --
|>|\/|<
/------------------------------------------------------------------\
|David M. Cooke http://arbutus.physics.mcmaster.ca/dmc/
|cookedm@physics.mcmaster.ca
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