/*
 * $Id: example0b.cpp,v 1.1 2007/08/15 19:44:55 brook Exp $
 */

/*
 * Copyright (c) 2007 Brook Milligan.
 * Distributed under the Boost Software License, Version 1.0. (See
 * accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 */

/*
 * The purpose of this example is to illustrate a solution to a
 * typical likelihood problem using the library.  It was created as an
 * example for the library documentation, and included here to ensure
 * that it compiles correctly.  Note that the actual implementations
 * of the classes and functions is meaningless, as they are not
 * relevant to illustrating the structure of the solution encapsulated
 * within the main() function.
 */

#include <cmath>
#include <iostream>
#include <vector>
#include <assert.h>
#include <boost/probability.hpp>
#include <boost/likelihood.hpp>

class GHCN_record { /* ... */ };

typedef std::vector<GHCN_record> GHCN_data_set;

class GlobalClimateModel
{
public:
  virtual ~GlobalClimateModel () { }
  virtual boost::probability probability (const GHCN_record&) const = 0;
};

class GlobalClimateModelFactory
{
public:
  GlobalClimateModel* operator () (const char*) const;
};

// read GHCN data set
std::istream& operator >> (std::istream&, GHCN_data_set&);

// output a likelihood
std::ostream& operator << (std::ostream&, const boost::likelihood&);

int
main ()
{
  typedef boost::probabilities::linear_domain linear_domain;

  GlobalClimateModelFactory climate_model_factory;
  GlobalClimateModel* climate_model = climate_model_factory("GCM");

  GHCN_data_set data;
  std::cin >> data;
  assert (data.size() == 590543); // XXX - illustrate large size of dataset

  boost::log_likelihood lnL;
  for (GHCN_data_set::const_iterator i = data.begin(); i != data.end(); ++i)
    {
      GHCN_record record = *i;
      boost::probability p (climate_model->probability(record));
      lnL *= p;
    }
  std::cout << "likelihood:  "
	    << boost::probabilities::domain_cast<linear_domain>(lnL)
	    << std::endl;

  return 0;
}

class GCM : public GlobalClimateModel
{
public:
  GCM () : GlobalClimateModel() { }
  virtual ~GCM () { }
  virtual boost::probability probability (const GHCN_record&) const
  { return boost::probability(1); }
};

GlobalClimateModel*
GlobalClimateModelFactory::operator () (const char*) const { return new GCM; }

std::istream&
operator >> (std::istream& s, GHCN_data_set& d)
{
  d = GHCN_data_set (590543);
  return s;
}

std::ostream&
operator << (std::ostream& s, const boost::likelihood& l)
{
  typedef boost::probabilities::linear_domain linear_domain;
  return s << boost::probabilities::value_cast<linear_domain>(l);
}