LatentModel.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) 2012 Viktor Gal
 * Copyright (C) 2012 Viktor Gal
 */

#include <shogun/latent/LatentModel.h>
#include <shogun/labels/BinaryLabels.h>

using namespace shogun;

CLatentModel::CLatentModel()
    : m_features(NULL),
    m_labels(NULL),
    m_do_caching(false),
    m_cached_psi(NULL)
{
    register_parameters();
}

CLatentModel::CLatentModel(CLatentFeatures* feats, CLatentLabels* labels, bool do_caching)
    : m_features(feats),
    m_labels(labels),
    m_do_caching(do_caching),
    m_cached_psi(NULL)
{
    register_parameters();
    SG_REF(m_features);
    SG_REF(m_labels);
}

CLatentModel::~CLatentModel()
{
    SG_UNREF(m_labels);
    SG_UNREF(m_features);
    SG_UNREF(m_cached_psi);
}

int32_t CLatentModel::get_num_vectors() const
{
    return m_features->get_num_vectors();
}

void CLatentModel::set_labels(CLatentLabels* labs)
{
    SG_UNREF(m_labels);
    SG_REF(labs);
    m_labels = labs;
}

CLatentLabels* CLatentModel::get_labels() const
{
    SG_REF(m_labels);
    return m_labels;
}

void CLatentModel::set_features(CLatentFeatures* feats)
{
    SG_UNREF(m_features);
    SG_REF(feats);
    m_features = feats;
}

void CLatentModel::argmax_h(const SGVector<float64_t>& w)
{
    int32_t num = get_num_vectors();
    CBinaryLabels* y = CBinaryLabels::obtain_from_generic(m_labels->get_labels());
    ASSERT(num > 0);
    ASSERT(num == m_labels->get_num_labels());
    

    // argmax_h only for positive examples
    for (int32_t i = 0; i < num; ++i)
    {
        if (y->get_label(i) == 1)
        {
            // infer h and set it for the argmax_h <w,psi(x,h)>
            CData* latent_data = infer_latent_variable(w, i);
            m_labels->set_latent_label(i, latent_data);
        }
    }
}

void CLatentModel::register_parameters()
{
    m_parameters->add((CSGObject**) &m_features, "features", "Latent features");
    m_parameters->add((CSGObject**) &m_labels, "labels", "Latent labels");
    m_parameters->add((CSGObject**) &m_cached_psi, "cached psi", "Cached PSI features after argmax_h");
    m_parameters->add(&m_do_caching, "do caching", "Indicate whether or not do PSI vector caching after argmax_h");
}


CLatentFeatures* CLatentModel::get_features() const
{
    SG_REF(m_features);
    return m_features;
}

void CLatentModel::cache_psi_features()
{
    if (m_do_caching)
    {
        if (m_cached_psi)
            SG_UNREF(m_cached_psi);
        m_cached_psi = this->get_psi_feature_vectors();
        SG_REF(m_cached_psi);
    }
}

CDotFeatures* CLatentModel::get_cached_psi_features() const
{
    if (m_do_caching)
    {
        SG_REF(m_cached_psi);
        return m_cached_psi;
    }
    return NULL;
}