C45ClassifierTree.h

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/*
 * Copyright (c) The Shogun Machine Learning Toolbox
 * Written (w) 2014 Parijat Mazumdar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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#ifndef _C45CLASSIFIERTREE_H__
#define _C45CLASSIFIERTREE_H__

#include <shogun/lib/config.h>

#include <shogun/multiclass/tree/TreeMachine.h>
#include <shogun/multiclass/tree/C45TreeNodeData.h>
#include <shogun/features/DenseFeatures.h>

namespace shogun
{

class CC45ClassifierTree : public CTreeMachine<C45TreeNodeData>
{
public:
    CC45ClassifierTree();

    virtual ~CC45ClassifierTree();

    virtual const char* get_name() const { return "C45ClassifierTree"; }

    virtual CMulticlassLabels* apply_multiclass(CFeatures* data=NULL);

    void prune_tree(CDenseFeatures<float64_t>* validation_data, CMulticlassLabels* validation_labels, float64_t epsilon=0.f);

    SGVector<float64_t> get_certainty_vector() const;

    void set_weights(SGVector<float64_t> w);

    SGVector<float64_t> get_weights() const;

    void clear_weights();

    void set_feature_types(SGVector<bool> ft);

    SGVector<bool> get_feature_types() const;

    void clear_feature_types();

protected:

    virtual bool train_machine(CFeatures* data=NULL);

private:

    node_t* C45train(CFeatures* data, SGVector<float64_t> weights, CMulticlassLabels* class_labels,
                            SGVector<int32_t> id_values, int level = 0);

    void prune_tree_from_current_node(CDenseFeatures<float64_t>* feats, CMulticlassLabels* gnd_truth, node_t* current, float64_t epsilon);

    float64_t informational_gain_attribute(int32_t attr_no, CFeatures* data, SGVector<float64_t> weights,
                                     CMulticlassLabels* class_labels);

    float64_t entropy(CMulticlassLabels* labels, SGVector<float64_t> weights);

    CMulticlassLabels* apply_multiclass_from_current_node(CDenseFeatures<float64_t>* feats, node_t* current, bool set_certainty=false);

    void init();

public:
    static const float64_t MISSING;

private:

    SGVector<bool> m_nominal;

    SGVector<float64_t> m_weights;

    SGVector<float64_t> m_certainty;

    bool m_types_set;

    bool m_weights_set;

};
} /* namespace shogun */

#endif /* _C45CLASSIFIERTREE_H__ */