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Question on Ramdom Number

 
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# 8  
Old 05-19-2005
Thanks everyone.
# 9  
Old 05-19-2005
Quote:
Originally Posted by jim mcnamara
vgersh99 -

put your code inside a tight loop, echo $rnd and you'll see the problem with it.
true - it's NOT a true random number generator - understood.
was it solaris 10 providing /dev/random - don't quite remember.

Quote:
Originally Posted by jim mcnamara
Plus, not everyone has nawk... Smilie Me, for example.
....how 'bout gawk? Smilie

I agree - it's not a generic solution
[bow in shame...]
# 10  
Old 05-19-2005
When I was writing my password generator I discovered that the ksh internal random number generator was not very good. I wound up writing my own, which turned out to be very hard. It's called "tigershark" and it is in my password generator called "swordfish". It's fast and portable. It has moderately long period, 9194221792649674751. And it passes the diehard test suite.

swordfish --- a password generator
# 11  
Old 05-19-2005
well how about this?

rnd=$(perl -e 'printf int(rand(0,36)+0.5)')
# 12  
Old 05-19-2005
Quote:
Originally Posted by reborg
well how about this?

rnd=$(perl -e 'printf int(rand(0,36)+0.5)')
it's a bit better then nawk, but still I'm still seeing repetitive values when put under the 'tight loop'.

don't really know if it's because the generator is better OR takes longer to load 'perl' [vs. loading nawk] and therefore the time-based [???] generation is a bit skewed [and better].
# 13  
Old 05-19-2005
Quote:
Originally Posted by Perderabo
When I was writing my password generator I discovered that the ksh internal random number generator was not very good. I wound up writing my own, which turned out to be very hard. It's called "tigershark" and it is in my password generator called "swordfish". It's fast and portable. It has moderately long period, 9194221792649674751. And it passes the diehard test suite.

swordfish --- a password generator
that's great - thanks for sharing!
# 14  
Old 05-19-2005
Quote:
Originally Posted by vgersh99
it's a bit better then nawk, but still I'm still seeing repetitive values when put under the 'tight loop'.

don't really know if it's because the generator is better OR takes longer to load 'perl' [vs. loading nawk] and therefore the time-based [???] generation is a bit skewed [and better].
No, it is just better, because the time used to seed it has finer granularity, you would get results similar to awk if you used:

perl -e 'srand(time()); printf int(rand(0,36)+0.5)'
 
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