[Numpy-discussion] Re: [SciPy-user] numarray complex comparisons

Tim Hochberg tim.hochberg at ieee.org
Mon Dec 9 08:15:05 EST 2002

> The questions just keep coming...
> We need to decide whether or not complex comparisons work.
> They do not work for Python scalars. Consistency would argue
> for them not working for numarray arrays. However some argue:
> 1) not allowing them defeats more generic programming. We agreed
> until we found that IDL doesn't support them either, and we never
> noticed. We are skeptical of this claim and would like to see
> real-life examples.
> 2) it is useful to allow comparisons since that would result in
> repeatable, sorting of values (e.g., to find duplicate values)
> for ordering purposes. Cannot this just be handled by the sort
> routines themselves? Why must this result in comparison operators
> working?
> In the absence of good examples for 1) or good arguments for 2)
> we propose to make complex comparisons generate exceptions.

What is the argument against allowing __eq__ to continue to work, while
disallowing __lt__ and friends. The former is well defined. I know comparing
floating point number for equality is a bit of a suckers game, but were
allowing it for floats and it's sometimes useful.

On second thought, maybe I'm just misinterpreting you here since __eq__
works fine for complex scalars.


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