From: "krusty.ar@..." <krusty.ar@...>
Date: 2008-07-02T02:47:14+09:00
Subject: Re: how to - quickly make permutations?

On Jul 1, 12:04 pm, Max Williams <toastkid.willi...@gmail.com> wrote:

> Thanks axel - i was thinking that some sort of 'homing in' approach
> might be better but couldn't work out how to go about it.  I'll have a
> look at this.

If you find it hard to define your "steps", you should try a genetic
algorithm aproach, using an array of 50 elements (representing if each
column is on the solution or not), and a function that measures the
fitness (how good is that combination).

Initially you create 100 random boolean arrays, select the best 20,
mix them in some way, for instance you could use the first half of one
array and the last half of another, or swaping a number of pairs of
columns in a single array (mutation), to create the remaining 80, and
repeat the process until your best candidate is good enough.

Of course the numbers can be tuned and will affect the efficience of
the program.

Lucas.