/*
    Copyright 2005-2015 Intel Corporation.  All Rights Reserved.

    This file is part of Threading Building Blocks. Threading Building Blocks is free software;
    you can redistribute it and/or modify it under the terms of the GNU General Public License
    version 2  as  published  by  the  Free Software Foundation.  Threading Building Blocks is
    distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
    implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    See  the GNU General Public License for more details.   You should have received a copy of
    the  GNU General Public License along with Threading Building Blocks; if not, write to the
    Free Software Foundation, Inc.,  51 Franklin St,  Fifth Floor,  Boston,  MA 02110-1301 USA

    As a special exception,  you may use this file  as part of a free software library without
    restriction.  Specifically,  if other files instantiate templates  or use macros or inline
    functions from this file, or you compile this file and link it with other files to produce
    an executable,  this file does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however invalidate any other
    reasons why the executable file might be covered by the GNU General Public License.
*/

//
// Self-organizing map
//
// support for self-ordering maps
#ifndef __SOM_H__
#define __SOM_H__

#include <vector>
#include <cstdlib>
#include <cmath>
#include <cfloat>
#include <iostream>
#include <cstdio>

#include "tbb/flow_graph.h"
#include "tbb/blocked_range2d.h"

using namespace tbb;
using namespace tbb::flow;

typedef blocked_range2d<int> subsquare_type;
typedef tuple<double,int,int> search_result_type;

std::ostream& operator<<( std::ostream &out, const search_result_type &s);

#define RADIUS 0  // for the std::gets
#define XV     1
#define YV     2

// to have single definitions of static variables, define _MAIN_C_ in the main program
// 
#ifdef _MAIN_C_
#define DEFINE // nothing
#define INIT(n) = n
#else // not in main file
#define DEFINE extern
#define INIT(n) // nothing
#endif  // _MAIN_C_

DEFINE int nElements INIT(3);  // length of input vectors, matching vector in map
DEFINE double max_learning_rate INIT(0.8);  // decays exponentially
DEFINE double radius_decay_rate;
DEFINE double learning_decay_rate INIT(0.005);
DEFINE double max_radius;
DEFINE bool extra_debug INIT(false);
DEFINE bool cancel_test INIT(false);

DEFINE int xMax INIT(100);
DEFINE int yMax INIT(100);
DEFINE int nPasses INIT(100);

enum InitializeType { InitializeRandom, InitializeGradient };
#define RED 0
#define GREEN 1
#define BLUE 2
class SOM_element;
void remark_SOM_element(const SOM_element &s);

// all SOM_element vectors are the same length (nElements), so we do not have
// to range-check the vector accesses.
class SOM_element {
    std::vector<double> w;
public:
    friend std::ostream& operator<<( std::ostream &out, const SOM_element &s);
    friend void remark_SOM_element(const SOM_element &s);
    SOM_element() : w(nElements,0.0) {}
    double &operator[](int indx) { return w.at(indx); }
    const double &operator[](int indx) const { return w.at(indx); }
    bool operator==(SOM_element const &other) const {
        for(size_t i=0;i<size();++i) {
            if(w[i] != other.w[i]) {
                return false;
            }
        }
        return true;
    }
    bool operator!=(SOM_element const &other) const { return !operator==(other); }
    void elementwise_max(SOM_element const &other) {
        for(size_t i = 0; i < w.size(); ++i) if(w[i] < other.w[i]) w[i] = other.w[i];
    }
    void elementwise_min(SOM_element const &other) {
        for(size_t i = 0; i < w.size(); ++i) if(w[i] > other.w[i]) w[i] = other.w[i];
    }
    size_t size() const { return w.size(); }
};

typedef std::vector<SOM_element> teaching_vector_type;

DEFINE SOM_element max_range;
DEFINE SOM_element min_range;

extern double randval( double lowlimit, double highlimit);

extern void find_data_ranges(teaching_vector_type &teaching, SOM_element &max_range, SOM_element &min_range );

extern void add_fraction_of_difference( SOM_element &to, SOM_element &from, double frac);

DEFINE teaching_vector_type my_teaching;

class SOMap {
    std::vector< std::vector< SOM_element > > my_map;
public:
    SOMap(int xSize, int ySize) {
        my_map.reserve(xSize);
        for(int i = 0; i < xSize; ++i) {
            my_map.push_back(teaching_vector_type());
            my_map[i].reserve(ySize);
            for(int j = 0; j < ySize;++j) {
                my_map[i].push_back(SOM_element());
            }
        }
    }
    size_t size() { return my_map.size(); }
    void initialize(InitializeType it, SOM_element &max_range, SOM_element &min_range);
    teaching_vector_type &operator[](int indx) { return my_map[indx]; }
    SOM_element &at(int xVal, int yVal) { return my_map[xVal][yVal]; }
    SOM_element &at(search_result_type const &s) { return my_map[flow::get<1>(s)][flow::get<2>(s)]; }
    void epoch_update( SOM_element const &s, int epoch, int min_x, int min_y, double radius, double learning_rate) {
        int min_xiter = (int)((double)min_x - radius);
        if(min_xiter < 0) min_xiter = 0;
        int max_xiter = (int)((double)min_x + radius);
        if(max_xiter > (int)my_map.size()-1) max_xiter = (int)(my_map.size()-1);
        blocked_range<int> br1(min_xiter, max_xiter, 1);
        epoch_update_range(s, epoch, min_x, min_y, radius, learning_rate, br1);
    }
    void epoch_update_range( SOM_element const &s, int epoch, int min_x, int min_y, double radius, double learning_rate, blocked_range<int> &r);
    void teach( teaching_vector_type &id);
    void debug_output();
    // find BMU given an input, returns distance
    double BMU_range(const SOM_element &s, int &xval, int &yval, subsquare_type &r);
    double BMU(const SOM_element &s, int &xval, int &yval) {
        subsquare_type br(0,(int)my_map.size(),1,0,(int)my_map[0].size(),1);
        return BMU_range(s, xval, yval, br);
    }
};

extern double distance_squared(SOM_element x, SOM_element y);
void remark_SOM_element(const SOM_element &s);

extern void readInputData();
#endif // __SOM_H__
