[Numpy-discussion] Four bugs in Numexpr and another repository

Ivan Vilata i Balaguer ivilata at carabos.com
Thu Apr 19 12:50:04 EDT 2007


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

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__'

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'

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"? ;) )

::

	Ivan Vilata i Balaguer   >qo<   http://www.carabos.com/
	       Cárabos Coop. V.  V  V   Enjoy Data
	                          ""
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