[Boost-users] boost::random::normal_distribution

From: Jeffrey Brent McBeth (mcbeth_at_[hidden])
Date: 2007-04-23 08:20:48

#include <boost/random.hpp>
#include <iostream>

int main(int argc, char *argv[])
{
        boost::mt19937 eng;
        boost::normal_distribution<> norm(0,1);
        std::cout << norm(eng) << std::endl;
}

Gives me a NaN everytime.  Looking at the code, it doesn't really surprise
me, as 

_r1 = eng();
_r2 = eng();
_cached_rho = sqrt(-result_type(2)*log(result_type(1)-_r2));

would only work if eng were in the range (0,1) with 0 being degenerate, and
1 being undefined.

Looking through the mt19937, that is returning a full UInt32.
Perhaps those two eng() should be replaced by uniform_01?

Jeffrey McBeth
-- 
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