PNorm.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/preprocessor/PNorm.h>
#include <shogun/preprocessor/DensePreprocessor.h>
#include <shogun/mathematics/Math.h>
#include <shogun/features/Features.h>

#ifdef HAVE_LAPACK
#include <shogun/mathematics/lapack.h>
#endif

using namespace shogun;

CPNorm::CPNorm ()
: CDensePreprocessor<float64_t>(),
 m_p (2.0)
{
    register_param ();
}

CPNorm::CPNorm (double p)
: CDensePreprocessor<float64_t>(),
 m_p (p)
{
    ASSERT (m_p >= 1.0);
    register_param ();
}

CPNorm::~CPNorm ()
{
}

bool CPNorm::init (CFeatures* features)
{
    ASSERT(features->get_feature_class()==C_DENSE);
    ASSERT(features->get_feature_type()==F_DREAL);

    return true;
}

void CPNorm::cleanup ()
{
}

bool CPNorm::load (FILE* f)
{
    SG_SET_LOCALE_C;
    SG_RESET_LOCALE;
    return false;
}

bool CPNorm::save (FILE* f)
{
    SG_SET_LOCALE_C;
    SG_RESET_LOCALE;
    return false;
}

SGMatrix<float64_t> CPNorm::apply_to_feature_matrix (CFeatures* features)
{
    SGMatrix<float64_t> feature_matrix=((CDenseFeatures<float64_t>*)features)->get_feature_matrix();

    for (int32_t i=0; i<feature_matrix.num_cols; i++)
    {
        float64_t* vec= &(feature_matrix.matrix[i*feature_matrix.num_rows]);
        float64_t norm = get_pnorm (vec, feature_matrix.num_rows);
        SGVector<float64_t>::scale_vector(1.0/norm, vec, feature_matrix.num_rows);
    }
    return feature_matrix;
}

SGVector<float64_t> CPNorm::apply_to_feature_vector (SGVector<float64_t> vector)
{
    float64_t* normed_vec = SG_MALLOC(float64_t, vector.vlen);
    float64_t norm = get_pnorm (vector.vector, vector.vlen);

    for (int32_t i=0; i<vector.vlen; i++)
        normed_vec[i]=vector.vector[i]/norm;

    return SGVector<float64_t>(normed_vec,vector.vlen);
}

void CPNorm::set_pnorm (double pnorm)
{
    ASSERT (pnorm >= 1.0);
    m_p = pnorm;
    register_param ();
}

double CPNorm::get_pnorm () const
{
    return m_p;
}

void CPNorm::register_param ()
{
    m_parameters->add (&m_p, "norm", "P-norm parameter");
}

inline float64_t CPNorm::get_pnorm (float64_t* vec, int32_t vec_len) const
{
    float64_t norm = 0.0;
    if (m_p == 1.0)
    {
        for (int i = 0; i < vec_len; ++i)
            norm += fabs (vec[i]);
    }
    else if (m_p == 2.0)
    {
        norm = SGVector<float64_t>::twonorm(vec, vec_len);
    }
    else
    {
        norm = SGVector<float64_t>::qnorm(vec, vec_len, m_p);
    }
        
    return norm;
}