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Home » U++ Library support » U++ Core » How to re-initialize random generator?
How to re-initialize random generator? [message #23035] Wed, 09 September 2009 17:30 Go to next message
Mindtraveller is currently offline  Mindtraveller
Messages: 917
Registered: August 2007
Location: Russia, Moscow rgn.
Experienced Contributor

It looks like Core has some advanced version of random numbers generator adopted from Makoto Matsumoto works (Core/Random.cpp).
My question is how to reinitialize this generator each time program start for it to generate different values on each start? (I mean, something like Randomize() ).
Re: How to re-initialize random generator? [message #23047 is a reply to message #23035] Thu, 10 September 2009 14:28 Go to previous messageGo to next message
mirek is currently offline  mirek
Messages: 13975
Registered: November 2005
Ultimate Member
Mindtraveller wrote on Wed, 09 September 2009 11:30

It looks like Core has some advanced version of random numbers generator adopted from Makoto Matsumoto works (Core/Random.cpp).
My question is how to reinitialize this generator each time program start for it to generate different values on each start? (I mean, something like Randomize() ).


Well, it is seeding automatically:

MTrand::MTrand()
{
	mti = N + 1;
	mag01[0] = 0;
	mag01[1] = MATRIX_A;
	dword seed[1024];
#ifdef PLATFORM_POSIX
	int fd = open("/dev/urandom", O_RDONLY);
	read(fd, seed, sizeof(seed));
#else
	for(int i = 0; i < 1024; i++) {
		Uuid uuid;
		CoCreateGuid((GUID *)&uuid);
		seed[i] = GetHashValue(uuid);
	}
#endif
	init_by_array(seed, 1024);
}


Re: How to re-initialize random generator? [message #23049 is a reply to message #23047] Thu, 10 September 2009 18:05 Go to previous messageGo to next message
Mindtraveller is currently offline  Mindtraveller
Messages: 917
Registered: August 2007
Location: Russia, Moscow rgn.
Experienced Contributor

Thanks for the reply, Mirek. Could you please tell if this random generator can be used to generate initial seed value for any cryptographically secure pseudo-random number generator (i.e. the one from OpenSSL which I consider using for next project).

[Updated on: Thu, 10 September 2009 18:05]

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Re: How to re-initialize random generator? [message #23050 is a reply to message #23049] Fri, 11 September 2009 01:53 Go to previous message
mirek is currently offline  mirek
Messages: 13975
Registered: November 2005
Ultimate Member
http://en.wikipedia.org/wiki/Mersenne_twister
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