StreamingVwFeatures.cpp

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/*
 * Copyright (c) 2009 Yahoo! Inc.  All rights reserved.  The copyrights
 * embodied in the content of this file are licensed under the BSD
 * (revised) open source license.
 *
 * 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) 2011 Shashwat Lal Das
 * Adaptation of Vowpal Wabbit v5.1.
 * Copyright (C) 2011 Berlin Institute of Technology and Max-Planck-Society.
 */

#include <shogun/features/StreamingVwFeatures.h>

using namespace shogun;

void CStreamingVwFeatures::set_vector_reader()
{
    parser.set_read_vector(&CStreamingFile::get_vector);
}

void CStreamingVwFeatures::set_vector_and_label_reader()
{
    parser.set_read_vector_and_label(&CStreamingFile::get_vector_and_label);
}

inline EFeatureType CStreamingVwFeatures::get_feature_type()
{
    return F_DREAL;
}

void CStreamingVwFeatures::init()
{
    working_file=NULL;
    seekable=false;
    current_length=-1;
    current_example=NULL;

    example_count = 0;
}

void CStreamingVwFeatures::init(CStreamingVwFile* file, bool is_labelled, int32_t size)
{
    init();
    has_labels = is_labelled;
    working_file = file;
    parser.init(file, is_labelled, size);
    parser.set_free_vector_after_release(false);
    seekable=false;

    // Get environment from the StreamingVwFile
    env = ((CStreamingVwFile*) file)->get_env();
    SG_REF(env);
}

void CStreamingVwFeatures::init(CStreamingVwCacheFile* file, bool is_labelled, int32_t size)
{
    init();
    has_labels = is_labelled;
    working_file = file;
    parser.init(file, is_labelled, size);
    parser.set_free_vector_after_release(false);
    seekable=true;

    // Get environment from the StreamingVwFile
    env = ((CStreamingVwCacheFile*) file)->get_env();
    SG_REF(env);
}

void CStreamingVwFeatures::setup_example(VwExample* ae)
{
    ae->pass = env->passes_complete;
    ae->num_features = 0;
    ae->total_sum_feat_sq = 1;
    ae->example_counter = ++example_count;
    ae->global_weight = ae->ld->weight;
    env->t += ae->global_weight;
    ae->example_t = env->t;

    // If some namespaces should be ignored, remove them
    if (env->ignore_some)
    {
        for (vw_size_t* i = ae->indices.begin; i != ae->indices.end; i++)
            if (env->ignore[*i])
            {
                ae->atomics[*i].erase();
                memmove(i,i+1,(ae->indices.end - (i+1))*sizeof(vw_size_t));
                ae->indices.end--;
                i--;
            }
    }

    // Add constant feature
    vw_size_t constant_namespace = 128;
    VwFeature temp = {1,constant_hash & env->mask};
    ae->indices.push(constant_namespace);
    ae->atomics[constant_namespace].push(temp);
    ae->sum_feat_sq[constant_namespace] = 0;

    if(env->stride != 1)
    {
        // Make room for per-feature information.
        vw_size_t stride = env->stride;
        for (vw_size_t* i = ae->indices.begin; i != ae->indices.end; i++)
            for(VwFeature* j = ae->atomics[*i].begin; j != ae->atomics[*i].end; j++)
                j->weight_index = j->weight_index*stride;
    }

    for (vw_size_t* i = ae->indices.begin; i != ae->indices.end; i++)
    {
        ae->num_features += ae->atomics[*i].end - ae->atomics[*i].begin;
        ae->total_sum_feat_sq += ae->sum_feat_sq[*i];
    }

    // For quadratic features
    for (int32_t k = 0; k < env->pairs.get_num_elements(); k++)
    {
        char* i = env->pairs.get_element(k);

        ae->num_features
            += (ae->atomics[(int32_t)(i[0])].end - ae->atomics[(int32_t)(i[0])].begin)
            *(ae->atomics[(int32_t)(i[1])].end - ae->atomics[(int32_t)(i[1])].begin);

        ae->total_sum_feat_sq += ae->sum_feat_sq[(int32_t)(i[0])]*ae->sum_feat_sq[(int32_t)(i[1])];
    }
}

void CStreamingVwFeatures::start_parser()
{
    if (!parser.is_running())
        parser.start_parser();
}

void CStreamingVwFeatures::end_parser()
{
    parser.end_parser();
}

bool CStreamingVwFeatures::get_next_example()
{
    bool ret_value;
    ret_value = (bool) parser.get_next_example(current_example,
                           current_length,
                           current_label);
    if (current_length < 1)
        return false;

    if (ret_value)
        setup_example(current_example);
    else
        return false;

    current_label = current_example->ld->label;
    current_length = current_example->num_features;

    return ret_value;
}

VwExample* CStreamingVwFeatures::get_example()
{
    return current_example;
}

float64_t CStreamingVwFeatures::get_label()
{
    ASSERT(has_labels);

    return current_label;
}

void CStreamingVwFeatures::release_example()
{
    env->example_number++;
    env->weighted_examples += current_example->ld->weight;

    if (current_example->ld->label == FLT_MAX)
        env->weighted_labels += 0;
    else
        env->weighted_labels += current_example->ld->label * current_example->ld->weight;

    env->total_features += current_example->num_features;
    env->sum_loss += current_example->loss;

    current_example->reset_members();
    parser.finalize_example();
}

int32_t CStreamingVwFeatures::get_dim_feature_space() const
{
    return current_length;
}

float32_t CStreamingVwFeatures::dot(CStreamingDotFeatures* df)
{
    SG_NOTIMPLEMENTED;
    return CMath::INFTY;
}

float32_t CStreamingVwFeatures::dense_dot(VwExample* &ex, const float32_t* vec2)
{
    float32_t ret = 0.;
    for (vw_size_t* i = ex->indices.begin; i!= ex->indices.end; i++)
    {
        for (VwFeature* f = ex->atomics[*i].begin; f != ex->atomics[*i].end; f++)
            ret += vec2[f->weight_index & env->thread_mask] * f->x;
    }
    return ret;
}

float32_t CStreamingVwFeatures::dense_dot(const float32_t* vec2, int32_t vec2_len)
{
    return dense_dot(current_example, vec2);
}

float32_t CStreamingVwFeatures::dense_dot(SGSparseVector<float32_t>* vec1, const float32_t* vec2)
{
    float32_t ret = 0.;
    for (int32_t i = 0; i < vec1->num_feat_entries; i++)
        ret += vec1->features[i].entry * vec2[vec1->features[i].feat_index & env->mask];

    return ret;
}

float32_t CStreamingVwFeatures::dense_dot_truncated(const float32_t* vec2, VwExample* &ex, float32_t gravity)
{
    float32_t ret = 0.;
    for (vw_size_t* i = ex->indices.begin; i != ex->indices.end; i++)
    {
        for (VwFeature* f = ex->atomics[*i].begin; f!= ex->atomics[*i].end; f++)
        {
            float32_t w = vec2[f->weight_index & env->thread_mask];
            float32_t wprime = real_weight(w,gravity);
            ret += wprime*f->x;
        }
    }

    return ret;
}

void CStreamingVwFeatures::add_to_dense_vec(float32_t alpha, VwExample* &ex, float32_t* vec2, int32_t vec2_len, bool abs_val)
{
    if (abs_val)
    {
        for (vw_size_t* i = ex->indices.begin; i != ex->indices.end; i++)
        {
            for (VwFeature* f = ex->atomics[*i].begin; f != ex->atomics[*i].end; f++)
                vec2[f->weight_index & env->thread_mask] += alpha * abs(f->x);
        }
    }
    else
    {
        for (vw_size_t* i = ex->indices.begin; i != ex->indices.end; i++)
        {
            for (VwFeature* f = ex->atomics[*i].begin; f != ex->atomics[*i].end; f++)
                vec2[f->weight_index & env->thread_mask] += alpha * f->x;
        }
    }
}

void CStreamingVwFeatures::add_to_dense_vec(float32_t alpha, float32_t* vec2, int32_t vec2_len, bool abs_val)
{
    add_to_dense_vec(alpha, current_example, vec2, vec2_len, abs_val);
}

int32_t CStreamingVwFeatures::get_num_features()
{
    return current_length;
}

EFeatureClass CStreamingVwFeatures::get_feature_class()
{
    return C_STREAMING_VW;
}