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Subject: Re: How to create a set of random integers for hashing?

Author: Ed Schröder

Date: 07:57:04 10/18/98

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>>#define LENGTH 64*12
>>
>>int random [LENGTH];
>>
>>int a,b,c,d,x;
>>
>>srand(9);                    // initialize prime number
>>
>>for (x=0; x<LENGTGH; x++)
>> { a=rand(); b=rand(); if (b & 1) a=a | 0x8000;
>>   c=rand(); d=rand(); if (d & 1) c=c | 0x8000;
>>   random[x]=(a<<16)+c;
>> }
>>
>>I wonder how good such a system is and how others do it.
>>
>>- Ed -
>
>
>First, I don't use "rand()" at all.  I ran some tests on it when
>I started the crafty project and didn't like the result.  Instead, I
>took the 32 bit random number generator from the well-known numerical
>book "Numerical Recipes".  It is far better, and you can certainly take
>the source to this directly from crafty since this piece of code is
>also public domain.

Can you post this code? In case you answer with a Crafty ".C" file where can
download Crafty's code?

- Ed -


>I use 64 bit random numbers for hashing and ran a lot of hamming distance
>tests to be sure the numbers looked ok, and was satisfied...



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