On Tue, Apr 24, 2012 at 3:02 PM, Błażej Jaworowski <jmvarelse@gmail.com> wrote:
I have a Monte Carlo simulation program (Ising model) in which I wanted to use Boost.Random number generators instead of one from Numerical Recipes. It works when the generator is called only in main, but when I use it inside function, I have "identifier not found". I don't want to initialize them each time I call a function because this will repeat the sequences of random number. Is there a way to overcome it?
I don't know much about typedefs and templates, so my initialization of the generator is just copied from some tutorial and changed in, I hope, appropriate places. 
Here is the example code (I wouldn't paste original program, it's too long, but here is the same problem)

// random_test.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "iostream"
#include <ctime>
#include <boost/random.hpp>
using namespace std;
namespace boost {
namespace random {
template<typename UIntType, int w, unsigned int p, unsigned int q>
class lagged_fibonacci_engine;
template<typename RealType, int w, unsigned int p, unsigned int q>
class lagged_fibonacci_01_engine;
typedef lagged_fibonacci_01_engine< double, 48, 607, 273 > lagged_fibonacci607;
typedef lagged_fibonacci_01_engine< double, 48, 1279, 418 > lagged_fibonacci1279;
typedef lagged_fibonacci_01_engine< double, 48, 2281, 1252 > lagged_fibonacci2281;
typedef lagged_fibonacci_01_engine< double, 48, 3217, 576 > lagged_fibonacci3217;
typedef lagged_fibonacci_01_engine< double, 48, 4423, 2098 > lagged_fibonacci4423;
typedef lagged_fibonacci_01_engine< double, 48, 9689, 5502 > lagged_fibonacci9689;
typedef lagged_fibonacci_01_engine< double, 48, 19937, 9842 > lagged_fibonacci19937;
typedef lagged_fibonacci_01_engine< double, 48, 23209, 13470 > lagged_fibonacci23209;
typedef lagged_fibonacci_01_engine< double, 48, 44497, 21034 > lagged_fibonacci44497;
}
}

void generate();

int _tmain(int argc, _TCHAR* argv[])
{const int rangeMin = 1;
const int rangeMax = 10;
typedef boost::uniform_real<> NumberDistribution;
typedef boost::random::lagged_fibonacci9689 RandomNumberGenerator;
typedef boost::variate_generator<RandomNumberGenerator&,
NumberDistribution> Generator;
NumberDistribution distribution(rangeMin, rangeMax);
RandomNumberGenerator generator;
Generator numberGenerator(generator, distribution);
  generator.seed(time(0)); // seed with the current time 
generate();
return 0;
}
void generate(){cout << numberGenerator() << endl;}

Why don't you just pass a reference to your numberGenerator object to your generate() function?

- Jeff