The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » sci.math.* » sci.math.num-analysis

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: generating random permutations on the fly
Replies: 6   Last Post: Sep 18, 2006 9:56 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
regis lebrun

Posts: 6
Registered: 9/14/06
Re: generating random permutations on the fly
Posted: Sep 14, 2006 8:01 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Han de Bruijn wrote:
> regis lebrun wrote:

> > [ ... ] but I can't use it if I want to generate a really huge
> > permutation (let's say n=10^9).

> Instead of asking more than seven wise men can answer, wouldn't you try
> to consider the possibility of sizing down your problem a little bit ..
> Han de Bruijn

First of all, thanks for this quick answer.

Of course I could tell the users to perform their Monte Carlo-like
simulations with less samples, but I don't really think it is the right
answer ;-). You know, if someone is able to compute some probability
with pure Monte Carlo by throwing 10^9 times the dices and evaluating a
cheap analytical function over this huge sample (it takes less than 1mn
in Matlab, standard PC computer), he will try to do the same with LHS,
and then, BOOM->out of memory.

By the way, I imagine that the underlying algorithmic problem is
interresting: how much information (i.e. how much memory) do I need to
store to be able to write down a permutation of [1, ..., n] without
storing it explicitely?

Best regards,


Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.