On Tue, Jan 27, 2015 at 10:05 AM, Nathaniel Smith <njs@pobox.com> wrote:
On Tue, Jan 27, 2015 at 4:20 PM, Guido van Rossum <guido@python.org> wrote:
> When does a program need *both* absolute and relative tolerance in a single
> test?

It's reasonably common in numpy, where the equivalent function is
vectorized to do multiple checks at once,

exactly -- as do a buch of the the unittest assertXXXX methods

or if folks write their own equivalent in a comprehension.

 
if 'math' doesn't provide this then many people will use libraries
that will or else write their own.

sure -- that's what been done for ages... you could say that about anything new being proposed for the stdlib.

 
I guess I don't have a good sense
of what the audience for 'math' is these days -- I'm sure it has one,
but aside from tiny one-off usages I'm not sure what it is. None of
the production numerical code I see even bothers importing it.

Well, I'm a heavy numpy user as well, but I still use the math module when I have something simple to calculate (actually, not so much simple as small -- if I'm not working with a lot of numbers) or if I don't want the numpy dependency.

A lot of people do at least some math with python -- I have no idea how many. And the statistics package was recently added -- I would have thought that would be next to useless without numpy, but shows you what I know.
 
It's
possible that it largely serves a kind of pedagogical role? high
schoolers learning to program etc.?

anyone learning python may need a bit of math -- there's some pretty basic stuff in there.

The most compelling argument I see is that if we care about unittest,
then it would be good to have a better alternative to
assertAlmostEqual. (...I don't know anyone who uses the unittest API
directly these days, though!)

I agree -- adding it to unitest would be a very good idea.

-Chris

 
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Christopher Barker, Ph.D.
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