seeding a boost::random number generator...?
I am little confused on how to see a random generator. What am I missing? // Grab the seed HighResTimer::Time time_secs = high_res_timer.getTime(); // Go ahead and truncate, it's just a seed boost::int32_t time = static_cast<boost::int32_t>(time_secs * 100000); // produces randomness out of thin air // see pseudo-random number generators boost::mt19937 rng; rng.seed(); // How do you seed this with the time? // distribution that maps to 0..1 // see random number distributions boost::uniform_real<> zero_to_one(0,1); // glues randomness with mapping boost::variate_generator<boost::mt19937&, boost::uniform_real<> > be_random zero_to_one);
Looks like you seed it by converting your time stamp to whatever "DataType" you're trying to get back and using it as an arg to seed: " lass random::mersenne_twister { public: typedef DataType result_type; . . . void seed(); void seed(DataType value); " -- http://www.boost.org/libs/random/random-generators.html#mersenne_twister Or you can take the - possibly more complicated - route of trying to figure out how to use the Generator template. Hope that helps, mike On Tue, 2007-10-23 at 12:00 -0500, Graham Reitz wrote:
I am little confused on how to see a random generator.
What am I missing?
// Grab the seed HighResTimer::Time time_secs = high_res_timer.getTime();
// Go ahead and truncate, it's just a seed boost::int32_t time = static_cast<boost::int32_t>(time_secs * 100000);
// produces randomness out of thin air // see pseudo-random number generators boost::mt19937 rng; rng.seed(); // How do you seed this with the time?
// distribution that maps to 0..1 // see random number distributions boost::uniform_real<> zero_to_one(0,1);
// glues randomness with mapping boost::variate_generator<boost::mt19937&, boost::uniform_real<> > be_random zero_to_one); _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
Thanks for the reply Mike. I am still stumped. Any ideas on how I can tell what type the "DataType" is? Graham On 10/23/07, Michael Linck <mgl@absolute-performance.com> wrote:
Looks like you seed it by converting your time stamp to whatever "DataType" you're trying to get back and using it as an arg to seed: " lass random::mersenne_twister { public: typedef DataType result_type; . . . void seed(); void seed(DataType value); " -- http://www.boost.org/libs/random/random-generators.html#mersenne_twister
Or you can take the - possibly more complicated - route of trying to figure out how to use the Generator template.
Hope that helps,
mike
On Tue, 2007-10-23 at 12:00 -0500, Graham Reitz wrote:
I am little confused on how to see a random generator.
What am I missing?
// Grab the seed HighResTimer::Time time_secs = high_res_timer.getTime();
// Go ahead and truncate, it's just a seed boost::int32_t time = static_cast<boost::int32_t>(time_secs * 100000);
// produces randomness out of thin air // see pseudo-random number generators boost::mt19937 rng; rng.seed(); // How do you seed this with the time?
// distribution that maps to 0..1 // see random number distributions boost::uniform_real<> zero_to_one(0,1);
// glues randomness with mapping boost::variate_generator<boost::mt19937&, boost::uniform_real<> > be_random zero_to_one); _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
Ok I got it. Yikes, talk about type safety. It really, really, wanted a boost::uint32_t for the seed parameter. I passed it a double to see what kind of warning I would receive, hoping it would tell me what the parent time is: warning: passing `double' for converting 1 of `void boost::random::mersenne_twister<UIntType, w, n, m, r, a, u, s, b, t , c, l, val>::seed(UIntType) [with UIntType = boost::uint32_t, int w = 32, int n = 624, int m = 397, int r = 31, UIntType a = -1727483681u, int u = 11, int s = 7, UIntType b = -1658038656u, int t = 15 , UIntType c = -272236544u, int l = 18, UIntType val = -948541730u]' Thanks again, Graham On 10/23/07, Graham Reitz <graham.cpp@gmail.com> wrote:
Thanks for the reply Mike. I am still stumped. Any ideas on how I can tell what type the "DataType" is?
Graham
On 10/23/07, Michael Linck <mgl@absolute-performance.com> wrote:
Looks like you seed it by converting your time stamp to whatever "DataType" you're trying to get back and using it as an arg to seed: " lass random::mersenne_twister { public: typedef DataType result_type; . . . void seed(); void seed(DataType value); " -- http://www.boost.org/libs/random/random-generators.html#mersenne_twister
Or you can take the - possibly more complicated - route of trying to figure out how to use the Generator template.
Hope that helps,
mike
On Tue, 2007-10-23 at 12:00 -0500, Graham Reitz wrote:
I am little confused on how to see a random generator.
What am I missing?
// Grab the seed HighResTimer::Time time_secs = high_res_timer.getTime();
// Go ahead and truncate, it's just a seed boost::int32_t time = static_cast<boost::int32_t>(time_secs * 100000);
// produces randomness out of thin air // see pseudo-random number generators boost::mt19937 rng; rng.seed(); // How do you seed this with the time?
// distribution that maps to 0..1 // see random number distributions boost::uniform_real<> zero_to_one(0,1);
// glues randomness with mapping boost::variate_generator<boost::mt19937&, boost::uniform_real<> > be_random zero_to_one); _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
mersenneTwister.seed( static_cast<boost::mt19937::result_type>(s) ); Avoiding hard-coded types is always a good idea. /Mikko Graham Reitz wrote:
Ok I got it. Yikes, talk about type safety. It really, really, wanted a boost::uint32_t for the seed parameter.
I passed it a double to see what kind of warning I would receive, hoping it would tell me what the parent time is:
warning: passing `double' for converting 1 of `void boost::random::mersenne_twister<UIntType, w, n, m, r, a, u, s, b, t , c, l, val>::seed(UIntType) [with UIntType = boost::uint32_t, int w = 32, int n = 624, int m = 397, int r = 31, UIntType a = -1727483681u, int u = 11, int s = 7, UIntType b = -1658038656u, int t = 15 , UIntType c = -272236544u, int l = 18, UIntType val = -948541730u]'
Thanks again, Graham
On 10/23/07, Graham Reitz <graham.cpp@gmail.com> wrote:
Thanks for the reply Mike. I am still stumped. Any ideas on how I can tell what type the "DataType" is?
Graham
On 10/23/07, Michael Linck <mgl@absolute-performance.com> wrote:
Looks like you seed it by converting your time stamp to whatever "DataType" you're trying to get back and using it as an arg to seed: " lass random::mersenne_twister { public: typedef DataType result_type; . . . void seed(); void seed(DataType value); " -- http://www.boost.org/libs/random/random-generators.html#mersenne_twister
Or you can take the - possibly more complicated - route of trying to figure out how to use the Generator template.
Hope that helps,
mike
On Tue, 2007-10-23 at 12:00 -0500, Graham Reitz wrote:
I am little confused on how to see a random generator.
What am I missing?
// Grab the seed HighResTimer::Time time_secs = high_res_timer.getTime();
// Go ahead and truncate, it's just a seed boost::int32_t time = static_cast<boost::int32_t>(time_secs * 100000);
// produces randomness out of thin air // see pseudo-random number generators boost::mt19937 rng; rng.seed(); // How do you seed this with the time?
// distribution that maps to 0..1 // see random number distributions boost::uniform_real<> zero_to_one(0,1);
// glues randomness with mapping boost::variate_generator<boost::mt19937&, boost::uniform_real<> > be_random zero_to_one); _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
-- :: Mikko Vainio <mikko.vainio@abo.fi> tel + 358 2 215 4600 :: Structural Bioinformatics Laboratory :: Department of Biochemistry and Pharmacy :: Abo Akademi University, Tykistokatu 6A, FI-20520 Turku Finland
participants (3)
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Graham Reitz -
Michael Linck -
Mikko Vainio