[Boost-users] boost::random issue with icc on Windows

10 Dec 2007

      Hello,

We are experiencing a problem with boost::random using icc on Windows 
under optimization.  If we compile with the -O1 option, we get correct 
behavior.  Compiling with -O2 or no -O option gives us a string of zeros.

We have compiled a small test case which shows this problem:

#include "boost/function.hpp"
#include "boost/random.hpp"

#include <iostream>
#include <iomanip>

using namespace std;

typedef boost::lagged_fibonacci607                 RGType;
typedef boost::uniform_smallint<>                  DistType;
typedef boost::variate_generator<RGType, DistType> GeneratorType;

int main()
{
    DistType mainDist(0,10000);
    RGType   mainEng((boost::uint32_t) 12);

    GeneratorType mainGen(mainEng, mainDist);

    for(size_t i = 0; i != 10; ++i)
        cout << mainGen() << ", ";

    cout << endl;
}

To date, I've done a lot of hunting trying different compiler options to 
attack this problem.  The compiler option which seems to have the most 
consistent effect, in that adding it makes the program work, whereas 
removing it makes it not is -Qunroll0.

I am guessing something in the optimization is causing the generator not 
to initialize properly, but I do not, at present, know how to solve it.

Has anyone else seen this, or have any ideas what might be going wrong?

I appreciate any ideas.

Thanks,

Geoff Wedig
Digital Domain