[boost] [Boost-bugs] [ boost-Bugs-1707940 ] random::normal_distribution

From: SourceForge.net (noreply_at_[hidden])
Date: 2007-04-26 05:53:18

Bugs item #1707940, was opened at 2007-04-26 09:53
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Category: random
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Jeffrey Brent McBeth (mcbeth)
Assigned to: Jens Maurer (jmaurer)
Summary: random::normal_distribution

Initial Comment:
random::normal_distribution always returns a NaN when presented with a UniformRandomNumberGenerator that provides values outside the range of (0,1).

So, for example, this will print a NaN.

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

int main(int argc, char *argv[])
{
        boost::mt19937 eng(40);
        boost::normal_distribution<> norm(0,1);
        std::cout << norm(eng) << std::endl;
}

Looking at the code, it is clear that for normal_distribution's answers to be defined, the values need to be in the range (0,1)

The attached patch uses uniform_real to restrict the range to [0,1).  Unfortunately, this leaves 0 as a fail point.  I don't see a clear way to fix that at the moment.

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