[racket] Modular arithmetic

2012/12/20 Erich Rast <erich at snafu.de>:
> Hi,
>
> For compatibility I need modular arithmetic for some
> standard numeric types such as signed 64bit integer, unsigned 64bit
> integer, signed 32 bit integer, and so on. Preferably it shouldn't be
> very slow.
>
> What's the best way to get this? Is there a package for this already?

For general modular arithmetic, you can do this using
a daily build:

#lang racket
(require math)

(with-modulus 5
  (list
   (mod 7)
   (mod+ 3 3)
   (mod* 3 7)
   (modexpt 3 2)))

The output is:
'(2 1 1 4)

See documentation here:

http://pre.racket-lang.org/docs/html/math/number-theory.html?q=math#(part._congruences)


-- 
Jens Axel Søgaard