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Re: Generating pseudo-random integers


From: Melikamp The Medley
Subject: Re: Generating pseudo-random integers
Date: Sat, 05 Feb 2011 05:14:43 -0500
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101213 Lightning/1.0b2 Lanikai/3.1.7

On 02/05/2011 02:20 AM, Bob Proulx wrote:
>> and link it with coreutils.
> Why?

So that I don't have to write a new PRNG, or anything, really, besides
a CL option parser. I would rather use ISAAC and randint.

Jim Meyering wrote:
> However, adding an *option* to shuf might make sense
Indeed, if shuf had such an option, I'd be perfectly happy just using that.

Bob Proulx wrote:
> Please also state your
> rationale for needing something different.
> Want a random number between 0 and 9?
>   awk 'BEGIN{srand();print int(10*rand());}'
> Want a thousand random numbers between 0 and 99?
>   awk 'BEGIN{srand();for(i=0;i<1000;++i){print int(100*rand());}}'

This should introduce the rounding bias, small as it is. I want
the integer-generating algorithm to have no bias on the assumption
that I have a truly random source. randint_choose is such an
algorithm. Just don't ask me where I am going to get this source :)

Jim Meyering wrote:
> $ perl -le 'foreach (1..20) { print int rand 1000 }'

Ditto. I know, I know, it's not the kind of bias that is likely
to matter in practice, but why settle for less than perfect?



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