[Patches] [ python-Patches-497487 ] support comparison of complex #s in fcmp

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Patches item #497487, was opened at 2001-12-28 17:09
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Category: Library (Lib)
Group: Python 2.3
>Status: Closed
>Resolution: Accepted
Priority: 5
Submitted By: Neal Norwitz (nnorwitz)
Assigned to: Neal Norwitz (nnorwitz)
Summary: support comparison of complex #s in fcmp

Initial Comment:
>From #494872, there was a suggestion to use
test_support.fcmp() to compare complex numbers.

This patch adds a comparison test for complex
numbers to test_complex and the support to compare
complex numbers in test_support.fcmp().

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>Comment By: Neal Norwitz (nnorwitz)
Date: 2001-12-29 06:35

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Checked in as 1.7 to test_complex.

I did what Tim suggested and did a vereq().

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Comment By: Tim Peters (tim_one)
Date: 2001-12-28 18:25

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test_complex.py already contains check_close() for fuzzy 
comparison of complex numbers.  The algorithm fcmp() uses 
isn't good enough for the comparison needs test_complex 
already has (I tried using it before, and it caused bogus 
test failures on Pentium + gcc under Linux -- long story, 
which I'll skip here).

So just use check_close, and skip the test_support part of 
this patch (people reading the general-purpose test_support 
shouldn't have to worry about the vagaries of complex 
numbers).  Or skip fuzzy comparison altogether!  You have 
an exact result here, and it would be fine to just do

test_support.vereq(complex(5.3, 9.8).conjugate(), 5.3-9.8j)

The folklore about never comparing floats for equality is 
nonsense (although good advice in most cases <wink>).

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