// Copyright (C) 2010  Davis E. King (davis@dlib.net)
// License: Boost Software License   See LICENSE.txt for the full license.


#include <sstream>
#include <string>
#include <cstdlib>
#include <ctime>
#include <dlib/statistics.h>
#include <dlib/rand.h>

#include "tester.h"

namespace  
{

    using namespace test;
    using namespace dlib;
    using namespace std;

    logger dlog("test.statistics");



    class statistics_tester : public tester
    {
    public:
        statistics_tester (
        ) :
            tester ("test_statistics",
                    "Runs tests on the statistics component.")
        {}

        void test_random_subset_selector ()
        {
            random_subset_selector<double> rand_set;

            for (int j = 0; j < 30; ++j)
            {
                print_spinner();

                running_stats<double> rs, rs2;

                rand_set.set_max_size(1000);

                for (double i = 0; i < 100000; ++i)
                {
                    rs.add(i);
                    rand_set.add(i);
                }


                for (unsigned long i = 0; i < rand_set.size(); ++i)
                    rs2.add(rand_set[i]);


                dlog << LDEBUG << "true mean:    " << rs.mean();
                dlog << LDEBUG << "true sampled: " << rs2.mean();
                double ratio = rs.mean()/rs2.mean();
                DLIB_TEST_MSG(0.96 < ratio  && ratio < 1.04, " ratio: " << ratio);
            }
        }

        void test_random_subset_selector2 ()
        {
            random_subset_selector<double> rand_set;
            DLIB_TEST(rand_set.next_add_accepts() == false);
            DLIB_TEST(rand_set.size() == 0);
            DLIB_TEST(rand_set.max_size() == 0);

            for (int j = 0; j < 30; ++j)
            {
                print_spinner();

                running_stats<double> rs, rs2;

                rand_set.set_max_size(1000);
                DLIB_TEST(rand_set.next_add_accepts() == true);

                for (double i = 0; i < 100000; ++i)
                {
                    rs.add(i);
                    if (rand_set.next_add_accepts())
                        rand_set.add(i);
                    else
                        rand_set.add();
                }

                DLIB_TEST(rand_set.size() == 1000);
                DLIB_TEST(rand_set.max_size() == 1000);

                for (unsigned long i = 0; i < rand_set.size(); ++i)
                    rs2.add(rand_set[i]);


                dlog << LDEBUG << "true mean:    " << rs.mean();
                dlog << LDEBUG << "true sampled: " << rs2.mean();
                double ratio = rs.mean()/rs2.mean();
                DLIB_TEST_MSG(0.96 < ratio  && ratio < 1.04, " ratio: " << ratio);
            }
        }

        void test_running_covariance (
        )
        {
            dlib::rand::float_1a rnd;
            std::vector<matrix<double,0,1> > vects;

            running_covariance<matrix<double,0,1> > cov, cov2;
            DLIB_TEST(cov.in_vector_size() == 0);

            for (unsigned long dims = 1; dims < 5; ++dims)
            {
                for (unsigned long samps = 2; samps < 10; ++samps)
                {
                    vects.clear();
                    cov.clear();
                    DLIB_TEST(cov.in_vector_size() == 0);
                    for (unsigned long i = 0; i < samps; ++i)
                    {
                        vects.push_back(randm(dims,1,rnd));
                        cov.add(vects.back());

                    }
                    DLIB_TEST(cov.in_vector_size() == dims);

                    DLIB_TEST(equal(mean(vector_to_matrix(vects)), cov.mean()));
                    DLIB_TEST_MSG(equal(covariance(vector_to_matrix(vects)), cov.covariance()),
                              max(abs(covariance(vector_to_matrix(vects)) - cov.covariance()))
                              << "   dims = " << dims << "   samps = " << samps
                              );
                }
            }

            for (unsigned long dims = 1; dims < 5; ++dims)
            {
                for (unsigned long samps = 2; samps < 10; ++samps)
                {
                    vects.clear();
                    cov.clear();
                    cov2.clear();
                    DLIB_TEST(cov.in_vector_size() == 0);
                    for (unsigned long i = 0; i < samps; ++i)
                    {
                        vects.push_back(randm(dims,1,rnd));
                        if ((i%2) == 0)
                            cov.add(vects.back());
                        else
                            cov2.add(vects.back());

                    }
                    DLIB_TEST((cov+cov2).in_vector_size() == dims);

                    DLIB_TEST(equal(mean(vector_to_matrix(vects)), (cov+cov2).mean()));
                    DLIB_TEST_MSG(equal(covariance(vector_to_matrix(vects)), (cov+cov2).covariance()),
                              max(abs(covariance(vector_to_matrix(vects)) - (cov+cov2).covariance()))
                              << "   dims = " << dims << "   samps = " << samps
                              );
                }
            }

        }

        void perform_test (
        )
        {
            test_random_subset_selector();
            test_random_subset_selector2();
            test_running_covariance();
        }
    } a;

}