From: Alex Chaffee <alex@...>
Date: 2012-01-27T05:54:32+09:00
Subject: Re: Microrant on Ruy's Math Skills

(1) I love this thread! Though every time I open it, I think some poor
guy named Ruy needs a math tutor...

(2) The amount of emotion and defensiveness around this issue is
staggering. It is the very definition of a religious argument. On one
side are people who think "math should work like I learned in grade
school," on the other are people who think "math does work like I
learned in college" (and the subset of those saying, "if you haven't
had my level of training then you are stupid"), and then there a bunch
of people in the middle saying, "you're both right, sort of!"

(3) I spend a lot of time teaching people programming, not writing
statistical algorithms, and I've written a unit testing library that
aims to be as unobtrusive as possible, so my main concern is to
minimize surprise while not undermining correctness. So naming my
method "close_to?" allows me to dodge the religious question "what is
equality?" and focus on getting noobies to understand just enough
complicated math to get their tests to pass, which basically amounts
to the lesson "floats are weird sometimes".

I do think it's important that Ruby Float == keeps working exactly
like C == and JavaScript == (kinda) and Python == though.

Or, what Yossef and Gavin said: "there are two different concerns at play
here. One is the standard problem with IEEE floating-point representation.
The other is deciding whether one number is "close enough" to another. One
of these could be the concern of a programming language, while the other
would be the concern of a particular program."

(4) Gavin, I *did* follow your message to the end, and the code helped
me really get your point. I also like Whitestone (I mean, "I Lk W")
and I might steal some of your comparators. Allow me to return the
favor by teaching you that Github supports line numbers in its URLs,
e.g.

https://github.com/gsinclair/whitestone/blob/master/lib/whitestone/assertion_classes.rb#L275-282

(5) How tragic is it that C broke a mathematical notation that had
worked just fine for hundreds of years and chose to define "=" as
assignment instead of equality? Amirite? Who's with me? :-)

-- 
Alex Chaffee - alex@stinky.com
http://alexchaffee.com
http://twitter.com/alexch