engine_init_options.go

package types

import (

    "log"

    "runtime"

)

var (

    // EngineInitOptions的默认值

    defaultNumSegmenterThreads       = runtime.NumCPU()

    defaultNumShards                 = 2

    defaultIndexerBufferLength       = runtime.NumCPU()

    defaultNumIndexerThreadsPerShard = runtime.NumCPU()

    defaultRankerBufferLength        = runtime.NumCPU()

    defaultNumRankerThreadsPerShard  = runtime.NumCPU()

    defaultDefaultRankOptions        = RankOptions{

        ScoringCriteria: RankByBM25{},

    }

    defaultIndexerInitOptions = IndexerInitOptions{

        IndexType:      FrequenciesIndex,

        BM25Parameters: &defaultBM25Parameters,

    }

    defaultBM25Parameters = BM25Parameters{

        K1: 2.0,

        B:  0.75,

    }

    defaultPersistentStorageShards = 8

)

type EngineInitOptions struct {

    // 是否使用分词器

    // 默认使用，否则在启动阶段跳过SegmenterDictionaries和StopTokenFile设置

    // 如果你不需要在引擎内分词，可以将这个选项设为true

    // 注意，如果你不用分词器，那么在调用IndexDocument时DocumentIndexData中的Content会被忽略

    NotUsingSegmenter bool

    // 半角逗号分隔的字典文件，具体用法见

    // sego.Segmenter.LoadDictionary函数的注释

    SegmenterDictionaries string

    // 停用词文件

    StopTokenFile string

    // 分词器线程数

    NumSegmenterThreads int

    // 索引器和排序器的shard数目

    // 被检索/排序的文档会被均匀分配到各个shard中

    NumShards int

    // 索引器的信道缓冲长度

    IndexerBufferLength int

    // 索引器每个shard分配的线程数

    NumIndexerThreadsPerShard int

    // 排序器的信道缓冲长度

    RankerBufferLength int

    // 排序器每个shard分配的线程数

    NumRankerThreadsPerShard int

    // 索引器初始化选项

    IndexerInitOptions *IndexerInitOptions

    // 默认的搜索选项

    DefaultRankOptions *RankOptions

    // 是否使用持久数据库，以及数据库文件保存的目录和裂分数目

    UsePersistentStorage    bool

    PersistentStorageFolder string

    PersistentStorageShards int

}

// 初始化EngineInitOptions，当用户未设定某个选项的值时用默认值取代

func (options *EngineInitOptions) Init() {

    if !options.NotUsingSegmenter {

        if options.SegmenterDictionaries == "" {

            log.Fatal("字典文件不能为空")

        }

    }

    if options.NumSegmenterThreads == 0 {

        options.NumSegmenterThreads = defaultNumSegmenterThreads

    }

    if options.NumShards == 0 {

        options.NumShards = defaultNumShards

    }

    if options.IndexerBufferLength == 0 {

        options.IndexerBufferLength = defaultIndexerBufferLength

    }

    if options.NumIndexerThreadsPerShard == 0 {

        options.NumIndexerThreadsPerShard = defaultNumIndexerThreadsPerShard

    }

    if options.RankerBufferLength == 0 {

        options.RankerBufferLength = defaultRankerBufferLength

    }

    if options.NumRankerThreadsPerShard == 0 {

        options.NumRankerThreadsPerShard = defaultNumRankerThreadsPerShard

    }

    if options.IndexerInitOptions == nil {

        options.IndexerInitOptions = &defaultIndexerInitOptions

    }

    if options.IndexerInitOptions.BM25Parameters == nil {

        options.IndexerInitOptions.BM25Parameters = &defaultBM25Parameters

    }

    if options.DefaultRankOptions == nil {

        options.DefaultRankOptions = &defaultDefaultRankOptions

    }

    if options.DefaultRankOptions.ScoringCriteria == nil {

        options.DefaultRankOptions.ScoringCriteria = defaultDefaultRankOptions.ScoringCriteria

    }

    if options.PersistentStorageShards == 0 {

        options.PersistentStorageShards = defaultPersistentStorageShards

    }

}