LinearKernel.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) 1999-2010 Soeren Sonnenburg
 * Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society
 * Copyright (C) 2010 Berlin Institute of Technology
 */

#include <shogun/lib/common.h>
#include <shogun/io/SGIO.h>
#include <shogun/features/Features.h>
#include <shogun/features/DotFeatures.h>
#include <shogun/kernel/LinearKernel.h>

using namespace shogun;

CLinearKernel::CLinearKernel()
: CDotKernel(0), normal(NULL), normal_length(0)
{
    properties |= KP_LINADD;
}

CLinearKernel::CLinearKernel(CDotFeatures* l, CDotFeatures* r)
: CDotKernel(0), normal(NULL), normal_length(0)
{
    properties |= KP_LINADD;
    init(l,r);
}

CLinearKernel::~CLinearKernel()
{
    cleanup();
}

bool CLinearKernel::init(CFeatures* l, CFeatures* r)
{
    CDotKernel::init(l, r);

    return init_normalizer();
}

void CLinearKernel::cleanup()
{
    delete_optimization();

    CKernel::cleanup();
}

void CLinearKernel::clear_normal()
{
    int32_t num = ((CDotFeatures*) lhs)->get_dim_feature_space();
    if (normal==NULL)
    {
        normal = SG_MALLOC(float64_t, num);
        normal_length=num;
    }

    memset(normal, 0, sizeof(float64_t)*normal_length);

    set_is_initialized(true);
}

void CLinearKernel::add_to_normal(int32_t idx, float64_t weight)
{
    ((CDotFeatures*) lhs)->add_to_dense_vec(
        normalizer->normalize_lhs(weight, idx), idx, normal, normal_length);
    set_is_initialized(true);
}

bool CLinearKernel::init_optimization(
    int32_t num_suppvec, int32_t* sv_idx, float64_t* alphas)
{
    clear_normal();

    for (int32_t i=0; i<num_suppvec; i++)
        add_to_normal(sv_idx[i], alphas[i]);

    set_is_initialized(true);
    return true;
}

bool CLinearKernel::init_optimization(CKernelMachine* km)
{
    clear_normal();

    int32_t num_suppvec=km->get_num_support_vectors();

    for (int32_t i=0; i<num_suppvec; i++)
        add_to_normal(km->get_support_vector(i), km->get_alpha(i));

    set_is_initialized(true);
    return true;
}

bool CLinearKernel::delete_optimization()
{
    SG_FREE(normal);
    normal_length=0;
    normal=NULL;
    set_is_initialized(false);

    return true;
}

float64_t CLinearKernel::compute_optimized(int32_t idx)
{
    ASSERT(get_is_initialized());
    float64_t result = ((CDotFeatures*) rhs)->
        dense_dot(idx, normal, normal_length);
    return normalizer->normalize_rhs(result, idx);
}