From: Joel VanderWerf <vjoel@...>
Date: 2002-01-03T08:12:58+09:00
Subject: [ruby-talk:30085] mathn questions


I'm writing some numerical stuff in Ruby and C, and I'd like to use
mathn.rb for the Ruby part. This is what irb's math mode uses to give
you '1/2 ==> 1/2' rather than '1/2 ==> 0'. Two questions:

1. Does changing integer division in this way interfere with anything in
the standard library? Any other consequences I should be aware of?
   The performance cost of using rationals is not a concern to me, even
considering the garbage creation, since C code is doing all the heavy
lifting anyway. I just want the Ruby front end to preserve as much
precision as possible.

2. Prime generation seems to happen redundantly in mathn.rb. It looks
like each time ** or gcd2 is called, the sequence of primes are
enumerated (partially, of course) *twice*. It would be better to treat
this sequence as static data and continue the enumeration as needed.
This is not a big deal for me, just a suggestion for whoever is
maintaining the code.

I have the Ruby 1.6.6 version of mathn.rb (which is dated 1998/01/16).