ContingencyTableEvaluation.cpp

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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) 2011 Sergey Lisitsyn
 * Copyright (C) 2011 Berlin Institute of Technology and Max-Planck-Society
 */

#include <shogun/evaluation/ContingencyTableEvaluation.h>
#include <shogun/labels/BinaryLabels.h>

using namespace shogun;

float64_t CContingencyTableEvaluation::evaluate(CLabels* predicted, CLabels* ground_truth)
{
    ASSERT(predicted->get_label_type()==LT_BINARY);
    ASSERT(ground_truth->get_label_type()==LT_BINARY);

    /* commented out: what if a machine only returns +1 in apply() ??
     * Heiko Strathamn */
//  predicted->ensure_valid();

    ground_truth->ensure_valid();
    compute_scores((CBinaryLabels*)predicted,(CBinaryLabels*)ground_truth);
    switch (m_type)
    {
        case ACCURACY:
            return get_accuracy();
        case ERROR_RATE:
            return get_error_rate();
        case BAL:
            return get_BAL();
        case WRACC:
            return get_WRACC();
        case F1:
            return get_F1();
        case CROSS_CORRELATION:
            return get_cross_correlation();
        case RECALL:
            return get_recall();
        case PRECISION:
            return get_precision();
        case SPECIFICITY:
            return get_specificity();
    }

    SG_NOTIMPLEMENTED;
    return 42;
}

inline EEvaluationDirection CContingencyTableEvaluation::get_evaluation_direction()
{
    switch (m_type)
    {
    case ACCURACY:
        return ED_MAXIMIZE;
    case ERROR_RATE:
        return ED_MINIMIZE;
    case BAL:
        return ED_MINIMIZE;
    case WRACC:
        return ED_MAXIMIZE;
    case F1:
        return ED_MAXIMIZE;
    case CROSS_CORRELATION:
        return ED_MAXIMIZE;
    case RECALL:
        return ED_MAXIMIZE;
    case PRECISION:
        return ED_MAXIMIZE;
    case SPECIFICITY:
        return ED_MAXIMIZE;
    default:
        SG_NOTIMPLEMENTED;
    }

    return ED_MINIMIZE;
}

void CContingencyTableEvaluation::compute_scores(CBinaryLabels* predicted, CBinaryLabels* ground_truth)
{
    ASSERT(ground_truth->get_label_type() == LT_BINARY);
    ASSERT(predicted->get_label_type() == LT_BINARY);

    if (predicted->get_num_labels()!=ground_truth->get_num_labels())
    {
        SG_ERROR("%s::compute_scores(): Number of predicted labels (%d) is not "
                "equal to number of ground truth labels (%d)!\n", get_name(),
                predicted->get_num_labels(), ground_truth->get_num_labels());
    }
    m_TP = 0.0;
    m_FP = 0.0;
    m_TN = 0.0;
    m_FN = 0.0;
    m_N = predicted->get_num_labels();

    for (int i=0; i<predicted->get_num_labels(); i++)
    {
        if (ground_truth->get_label(i)==1)
        {
            if (predicted->get_label(i)==1)
                m_TP += 1.0;
            else
                m_FN += 1.0;
        }
        else
        {
            if (predicted->get_label(i)==1)
                m_FP += 1.0;
            else
                m_TN += 1.0;
        }
    }
    m_computed = true;
}