From: Daniel Berger <Daniel.Berger@...>
Date: 2006-08-11T06:53:00+09:00
Subject: Confused by Bignum#remainder

Help a guy out who got B's and C's in math classes in college:

Ruby 1.8.4 on Solaris 10:

irb(main):013:0> -1234567890987654321.remainder(13731)
=> -6966
irb(main):014:0> -1234567890987654321.remainder(13731.24)
=> -9906.22531493148
irb(main):015:0> -1234567890987654321.modulo(13731)
=> 6765
irb(main):016:0> -1234567890987654321.modulo(13731.24)
=> 3825.01468506852

Basically, I'm trying to figure out the nuances of Bignum#remainder vs 
Bignum#modulo.  To confuse myself even further K&R (2nd ed, p. 41) says you 
can't do modulus on double or long, and that the sign result is machine 
dependent for negative operands.

Can someone explain the subtleties of this to me (or point me to a link that 
does)?  An archive search didn't reveal anything obvious.

Perhaps the documentation in bignum.c needs further exposition?  Or should I 
just *know* this?

Thanks,

Dan

PS - I did try to read over the bigdivrem() private function in bignum.c but, 
like, whoa.


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