GMNPSVM.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) 1999-2008 Vojtech Franc, xfrancv@cmp.felk.cvut.cz
 * Copyright (C) 1999-2008 Center for Machine Perception, CTU FEL Prague
 */

#include <shogun/io/SGIO.h>
#include <shogun/labels/MulticlassLabels.h>
#include <shogun/multiclass/GMNPSVM.h>
#include <shogun/multiclass/GMNPLib.h>
#include <shogun/multiclass/MulticlassOneVsRestStrategy.h>

#define INDEX(ROW,COL,DIM) (((COL)*(DIM))+(ROW))
#define MINUS_INF INT_MIN
#define PLUS_INF  INT_MAX
#define KDELTA(A,B) (A==B)
#define KDELTA4(A1,A2,A3,A4) ((A1==A2)||(A1==A3)||(A1==A4)||(A2==A3)||(A2==A4)||(A3==A4))

using namespace shogun;

CGMNPSVM::CGMNPSVM()
: CMulticlassSVM(new CMulticlassOneVsRestStrategy())
{
    init();
}

CGMNPSVM::CGMNPSVM(float64_t C, CKernel* k, CLabels* lab)
: CMulticlassSVM(new CMulticlassOneVsRestStrategy(), C, k, lab)
{
    init();
}

CGMNPSVM::~CGMNPSVM()
{
    if (m_basealphas != NULL) SG_FREE(m_basealphas);
}

void
CGMNPSVM::init()
{
    m_parameters->add_matrix(&m_basealphas,
                             &m_basealphas_y, &m_basealphas_x,
                             "m_basealphas",
                             "Is the basic untransformed alpha.");

    m_basealphas = NULL, m_basealphas_y = 0, m_basealphas_x = 0;
}

bool CGMNPSVM::train_machine(CFeatures* data)
{
    ASSERT(m_kernel)
    ASSERT(m_labels && m_labels->get_num_labels())
    ASSERT(m_labels->get_label_type() == LT_MULTICLASS)

    if (data)
    {
        if (m_labels->get_num_labels() != data->get_num_vectors())
        {
            SG_ERROR("%s::train_machine(): Number of training vectors (%d) does"
                    " not match number of labels (%d)\n", get_name(),
                    data->get_num_vectors(), m_labels->get_num_labels());
        }
        m_kernel->init(data, data);
    }

    int32_t num_data = m_labels->get_num_labels();
    int32_t num_classes = m_multiclass_strategy->get_num_classes();
    int32_t num_virtual_data= num_data*(num_classes-1);

    SG_INFO("%d trainlabels, %d classes\n", num_data, num_classes)

    float64_t* vector_y = SG_MALLOC(float64_t, num_data);
    for (int32_t i=0; i<num_data; i++)
    {
        vector_y[i] = ((CMulticlassLabels*) m_labels)->get_label(i)+1;

    }

    float64_t C = get_C();
    int32_t tmax = 1000000000;
    float64_t tolabs = 0;
    float64_t tolrel = get_epsilon();

    float64_t reg_const=0;
    if( C!=0 )
        reg_const = 1/(2*C);


    float64_t* alpha = SG_MALLOC(float64_t, num_virtual_data);
    float64_t* vector_c = SG_MALLOC(float64_t, num_virtual_data);
    memset(vector_c, 0, num_virtual_data*sizeof(float64_t));

    float64_t thlb = 10000000000.0;
    int32_t t = 0;
    float64_t* History = NULL;
    int32_t verb = 0;

    CGMNPLib mnp(vector_y,m_kernel,num_data, num_virtual_data, num_classes, reg_const);

    mnp.gmnp_imdm(vector_c, num_virtual_data, tmax,
                  tolabs, tolrel, thlb, alpha, &t, &History, verb);

    /* matrix alpha [num_classes x num_data] */
    float64_t* all_alphas= SG_MALLOC(float64_t, num_classes*num_data);
    memset(all_alphas,0,num_classes*num_data*sizeof(float64_t));

    /* bias vector b [num_classes x 1] */
    float64_t* all_bs=SG_MALLOC(float64_t, num_classes);
    memset(all_bs,0,num_classes*sizeof(float64_t));

    /* compute alpha/b from virt_data */
    for(int32_t i=0; i < num_classes; i++ )
    {
        for(int32_t j=0; j < num_virtual_data; j++ )
        {
            int32_t inx1=0;
            int32_t inx2=0;

            mnp.get_indices2( &inx1, &inx2, j );

            all_alphas[(inx1*num_classes)+i] +=
                alpha[j]*(KDELTA(vector_y[inx1],i+1)-KDELTA(i+1,inx2));
            all_bs[i] += alpha[j]*(KDELTA(vector_y[inx1],i+1)-KDELTA(i+1,inx2));
        }
    }

    create_multiclass_svm(num_classes);

    for (int32_t i=0; i<num_classes; i++)
    {
        int32_t num_sv=0;
        for (int32_t j=0; j<num_data; j++)
        {
            if (all_alphas[j*num_classes+i] != 0)
                num_sv++;
        }
        ASSERT(num_sv>0)
        SG_DEBUG("svm[%d] has %d sv, b=%f\n", i, num_sv, all_bs[i])

        CSVM* svm=new CSVM(num_sv);

        int32_t k=0;
        for (int32_t j=0; j<num_data; j++)
        {
            if (all_alphas[j*num_classes+i] != 0)
            {
                svm->set_alpha(k, all_alphas[j*num_classes+i]);
                svm->set_support_vector(k, j);
                k++;
            }
        }

        svm->set_bias(all_bs[i]);
        set_svm(i, svm);
    }

    if (m_basealphas != NULL) SG_FREE(m_basealphas);
    m_basealphas_y = num_classes, m_basealphas_x = num_data;
    m_basealphas = SG_MALLOC(float64_t, m_basealphas_y*m_basealphas_x);
    for (index_t i=0; i<m_basealphas_y*m_basealphas_x; i++)
        m_basealphas[i] = 0.0;

    for(index_t j=0; j<num_virtual_data; j++)
    {
        index_t inx1=0, inx2=0;

        mnp.get_indices2(&inx1, &inx2, j);
        m_basealphas[inx1*m_basealphas_y + (inx2-1)] = alpha[j];
    }

    SG_FREE(vector_c);
    SG_FREE(alpha);
    SG_FREE(all_alphas);
    SG_FREE(all_bs);
    SG_FREE(vector_y);
    SG_FREE(History);

    return true;
}

float64_t*
CGMNPSVM::get_basealphas_ptr(index_t* y, index_t* x)
{
    if (y == NULL || x == NULL) return NULL;

    *y = m_basealphas_y, *x = m_basealphas_x;
    return m_basealphas;
}