SVM.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) 1999-2009 Soeren Sonnenburg
 * Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society
 */

#include "lib/common.h"
#include "lib/io.h"
#include "base/Parallel.h"

#include "classifier/svm/SVM.h"
#include "classifier/mkl/MKL.h"

#include <string.h>

#ifndef WIN32
#include <pthread.h>
#endif

#ifdef HAVE_BOOST_SERIALIZATION
#include <boost/serialization/export.hpp>
//BOOST_SERIALIZATION_ASSUME_ABSTRACT(CSVM);
#endif //HAVE_BOOST_SERIALIZATION

using namespace shogun;

CSVM::CSVM(int32_t num_sv)
: CKernelMachine()
{
    set_defaults(num_sv);

    parameters.add(&C1, "C1");
    parameters.add(&C2, "C2");
}

CSVM::CSVM(float64_t C, CKernel* k, CLabels* lab)
: CKernelMachine()
{
    set_defaults();
    set_C(C,C);
    set_labels(lab);
    set_kernel(k);

    parameters.add(&C1, "C1");
    parameters.add(&C2, "C2");
}

CSVM::~CSVM()
{
    SG_UNREF(mkl);
}

void CSVM::set_defaults(int32_t num_sv)
{
    callback=NULL;
    mkl=NULL;

    svm_loaded=false;

    epsilon=1e-5;
    tube_epsilon=1e-2;

    nu=0.5;
    C1=1;
    C2=1;

    objective=0;

    qpsize=41;
    use_bias=true;
    use_shrinking=true;
    use_batch_computation=true;
    use_linadd=true;

    if (num_sv>0)
        create_new_model(num_sv);
}

bool CSVM::load(FILE* modelfl)
{
    bool result=true;
    char char_buffer[1024];
    int32_t int_buffer;
    float64_t double_buffer;
    int32_t line_number=1;

    if (fscanf(modelfl,"%4s\n", char_buffer)==EOF)
    {
        result=false;
        SG_ERROR( "error in svm file, line nr:%d\n", line_number);
    }
    else
    {
        char_buffer[4]='\0';
        if (strcmp("%SVM", char_buffer)!=0)
        {
            result=false;
            SG_ERROR( "error in svm file, line nr:%d\n", line_number);
        }
        line_number++;
    }

    int_buffer=0;
    if (fscanf(modelfl," numsv=%d; \n", &int_buffer) != 1)
    {
        result=false;
        SG_ERROR( "error in svm file, line nr:%d\n", line_number);
    }

    if (!feof(modelfl))
        line_number++;

    SG_INFO( "loading %ld support vectors\n",int_buffer);
    create_new_model(int_buffer);

    if (fscanf(modelfl," kernel='%s'; \n", char_buffer) != 1)
    {
        result=false;
        SG_ERROR( "error in svm file, line nr:%d\n", line_number);
    }

    if (!feof(modelfl))
        line_number++;

    double_buffer=0;

    if (fscanf(modelfl," b=%lf; \n", &double_buffer) != 1)
    {
        result=false;
        SG_ERROR( "error in svm file, line nr:%d\n", line_number);
    }

    if (!feof(modelfl))
        line_number++;

    set_bias(double_buffer);

    if (fscanf(modelfl,"%8s\n", char_buffer) == EOF)
    {
        result=false;
        SG_ERROR( "error in svm file, line nr:%d\n", line_number);
    }
    else
    {
        char_buffer[9]='\0';
        if (strcmp("alphas=[", char_buffer)!=0)
        {
            result=false;
            SG_ERROR( "error in svm file, line nr:%d\n", line_number);
        }
        line_number++;
    }

    for (int32_t i=0; i<get_num_support_vectors(); i++)
    {
        double_buffer=0;
        int_buffer=0;

        if (fscanf(modelfl," \[%lf,%d]; \n", &double_buffer, &int_buffer) != 2)
        {
            result=false;
            SG_ERROR( "error in svm file, line nr:%d\n", line_number);
        }

        if (!feof(modelfl))
            line_number++;

        set_support_vector(i, int_buffer);
        set_alpha(i, double_buffer);
    }

    if (fscanf(modelfl,"%2s", char_buffer) == EOF)
    {
        result=false;
        SG_ERROR( "error in svm file, line nr:%d\n", line_number);
    }
    else
    {
        char_buffer[3]='\0';
        if (strcmp("];", char_buffer)!=0)
        {
            result=false;
            SG_ERROR( "error in svm file, line nr:%d\n", line_number);
        }
        line_number++;
    }

    svm_loaded=result;
    return result;
}

bool CSVM::save(FILE* modelfl)
{
    if (!kernel)
        SG_ERROR("Kernel not defined!\n");

    SG_INFO( "Writing model file...");
    fprintf(modelfl,"%%SVM\n");
    fprintf(modelfl,"numsv=%d;\n", get_num_support_vectors());
    fprintf(modelfl,"kernel='%s';\n", kernel->get_name());
    fprintf(modelfl,"b=%+10.16e;\n",get_bias());

    fprintf(modelfl, "alphas=\[\n");

    for(int32_t i=0; i<get_num_support_vectors(); i++)
        fprintf(modelfl,"\t[%+10.16e,%d];\n",
                CSVM::get_alpha(i), get_support_vector(i));

    fprintf(modelfl, "];\n");

    SG_DONE();
    return true ;
}

void CSVM::set_callback_function(CMKL* m, bool (*cb)
        (CMKL* mkl, const float64_t* sumw, const float64_t suma))
{
    SG_UNREF(mkl);
    mkl=m;
    SG_REF(mkl);

    callback=cb;
}

float64_t CSVM::compute_svm_dual_objective()
{
    int32_t n=get_num_support_vectors();

    if (labels && kernel)
    {
        objective=0;
        for (int32_t i=0; i<n; i++)
        {
            int32_t ii=get_support_vector(i);
            objective-=get_alpha(i)*labels->get_label(ii);

            for (int32_t j=0; j<n; j++)
            {
                int32_t jj=get_support_vector(j);
                objective+=0.5*get_alpha(i)*get_alpha(j)*kernel->kernel(ii,jj);
            }
        }
    }
    else
        SG_ERROR( "cannot compute objective, labels or kernel not set\n");

    return objective;
}

float64_t CSVM::compute_svm_primal_objective()
{
    int32_t n=get_num_support_vectors();
    float64_t regularizer=0;
    float64_t loss=0;

    if (labels && kernel)
    {
        for (int32_t i=0; i<n; i++)
        {
            int32_t ii=get_support_vector(i);
            for (int32_t j=0; j<n; j++)
            {
                int32_t jj=get_support_vector(j);
                regularizer-=0.5*get_alpha(i)*get_alpha(j)*kernel->kernel(ii,jj);
            }

            loss-=C1*CMath::max(0.0, 1.0-get_label(ii)*classify_example(ii));
        }
    }
    else
        SG_ERROR( "cannot compute objective, labels or kernel not set\n");

    return regularizer+loss;
}


float64_t* CSVM::get_linear_term_array() {

    float64_t* a = new float64_t[linear_term.size()];
    std::copy( linear_term.begin(), linear_term.end(), a);

    return a;

}



void CSVM::set_linear_term(std::vector<float64_t> lin)
{

    if (!labels)
        SG_ERROR("Please assign labels first!\n");

    int32_t num_labels=labels->get_num_labels();

    if (num_labels!=(int32_t) lin.size())
    {
        SG_ERROR("Number of labels (%d) does not match number"
                "of entries (%d) in linear term \n", num_labels, lin.size());
    }

    linear_term = lin;

}


std::vector<float64_t> CSVM::get_linear_term() {

    return linear_term;

}