Re: [Seed7-users] Q: random number generation

[Thomas M. <tho...@gm...>]

On Fri, 20 Apr 2012 00:14:36 +0200, mok-kong shen <mok...@t-...> wrote:
> Hallo,
> 
> I am a newcomer of the list and wish to know: Is it possible to somehow
> obtain in seed7 the functionality akin to e.g. that of SystemRandom of
> Python?

Do you mean an access to the random number generator of the
operating system?
AFAICS Python does not guarantee that SystemRandom is available
on all operating systems. Seed7 tries to provide APIs that are
always available. Besides this problem it would be possible to
support such functionality. As quick solution for Linux you could
just open "/dev/urandom" and obtain the random values from there.

I am not a Python expert.
Does SystemRandom plug in its functionality to the standard random function?
Is there a class for random generators and SystemRandom is just one of them?

The random function of Seed7 (rand) has currently no possibility to plug
in a random number generator backend (but this extension could be done).

It would also be possible to introduce a randomGenerator interface as
backend for 'rand'. In this case there could be a built-in and a system
random number generator.

The Seed7 function 'rand' is overloaded for many types. Creating an
extra function for system random values would also make it necessary to
overload it for many types. Therefore I had the idea with a random
number generator backend. Probably Python or other languages already
have it. I was just too lazy to check.

If you are interested in the Seed7 implementation of rand you can
look at the function uint_rand in int_rtl.c which is used as
hardcoded random number generator backend. The functions intRand,
fltRand and bigRand are based on uint_rand.

Does this answer your question?

Greetings Thomas Mertes
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