MulticlassStrategy.h

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/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * Written (W) 2012 Chiyuan Zhang
 * Written (W) 2013 Shell Hu and Heiko Strathmann
 * Copyright (C) 2012 Chiyuan Zhang
 */

#ifndef MULTICLASSSTRATEGY_H__
#define MULTICLASSSTRATEGY_H__

#include <shogun/base/SGObject.h>
#include <shogun/labels/BinaryLabels.h>
#include <shogun/labels/MulticlassLabels.h>
#include <shogun/multiclass/RejectionStrategy.h>
#include <shogun/mathematics/Statistics.h>

namespace shogun
{

enum EProbHeuristicType
{
    PROB_HEURIS_NONE = 0,
    OVA_NORM = 1,
    OVA_SOFTMAX = 2,
    OVO_PRICE = 3,
    OVO_HASTIE = 4,
    OVO_HAMAMURA = 5
};

class CMulticlassStrategy: public CSGObject
{
public:
    CMulticlassStrategy();

    CMulticlassStrategy(EProbHeuristicType prob_heuris);

    virtual ~CMulticlassStrategy() {}

    virtual const char* get_name() const
    {
        return "MulticlassStrategy";
    };

    void set_num_classes(int32_t num_classes)
    {
        m_num_classes = num_classes;
    }

    int32_t get_num_classes() const
    {
        return m_num_classes;
    }

    CRejectionStrategy *get_rejection_strategy()
    {
        SG_REF(m_rejection_strategy);
        return m_rejection_strategy;
    }

    void set_rejection_strategy(CRejectionStrategy *rejection_strategy)
    {
        SG_REF(rejection_strategy);
        SG_UNREF(m_rejection_strategy);
        m_rejection_strategy = rejection_strategy;
    }

    virtual void train_start(CMulticlassLabels *orig_labels, CBinaryLabels *train_labels);

    virtual bool train_has_more()=0;

    virtual SGVector<int32_t> train_prepare_next();

    virtual void train_stop();

    virtual int32_t decide_label(SGVector<float64_t> outputs)=0;
    
    virtual SGVector<index_t> decide_label_multiple_output(SGVector<float64_t> outputs, int32_t n_outputs)
    {
        SG_NOTIMPLEMENTED
        return SGVector<index_t>();
    }

    virtual int32_t get_num_machines()=0;

    EProbHeuristicType get_prob_heuris_type()
    {
        return m_prob_heuris;
    }

    void set_prob_heuris_type(EProbHeuristicType prob_heuris)
    {
        m_prob_heuris = prob_heuris;
    }

    virtual void rescale_outputs(SGVector<float64_t> outputs)
    {
        SG_NOTIMPLEMENTED
    }   

    virtual void rescale_outputs(SGVector<float64_t> outputs,
            const SGVector<float64_t> As, const SGVector<float64_t> Bs)
    {
        SG_NOTIMPLEMENTED
    }   

private:
    void init();

protected:

    CRejectionStrategy* m_rejection_strategy; 
    CBinaryLabels *m_train_labels;    
    CMulticlassLabels *m_orig_labels; 
    int32_t m_train_iter;             
    int32_t m_num_classes;            
    EProbHeuristicType m_prob_heuris; 
};

} // namespace shogun

#endif /* end of include guard: MULTICLASSSTRATEGY_H__ */