Re: [Boost-users] [random] getting a 50% probability generator

From: Jeffrey Holle (jeffreyholle_at_[hidden])
Date: 2007-10-05 14:08:25

Brian Stadler wrote:
> A few things,
> 
> First, try this when creating your uniform_01 object,
> 
> typedef boost::uniform_01<boost::mt19937> random_real;  <--you 
> typedef'ed it here.
> random_real actual_generator;
> actual_generator() <----to output numbers between 0 and 1.
> 
> Two,  don't use uniform_01.  The uniform_real class works much better 
> and defaults to between 0 and 1.
> 
> 
> Three,  it looks like you are wanting random ints 0 and 1, not random 
> real numbers between 0 and 1.  For this have a look at the uniform_int 
> or uniform_smallint class.  They are probably what you are looking for.
> 
> Hope this helps.
> 
> Brian
Thanks for this information.
It looks like I indeed need uniform_smallint, but I'm having trouble 
with it.  This is what I'm trying to compile:

   std::tr1::mt19937 rng;
   boost::uniform_smallint<int> six(1,6);
   boost::variate_generator<std::tr1::mt19937&, 
boost::uniform_smallint<int> > die(rng, six);
   int x = die();

Note this from a boost webpage, with slight modifications.

The compiler error I'm getting is:

../test.cpp:15: error: no matching function for call to 
'boost::variate_generator<std::tr1::mt19937&, 
boost::uniform_smallint<int> >::variate_generator()'
$BOOST_ROOT/boost/random/variate_generator.hpp:97: note: candidates are: 
boost::variate_generator<Engine, 
Distribution>::variate_generator(Engine, Distribution) [with Engine = 
std::tr1::mt19937&, Distribution = boost::uniform_smallint<int>]

Can somebody point out what my problem is?