Indexes to create efficient representations of data. More...

Classes
class	absolute_discount
	Implements the absolute discounting smoothing method. More...

class	cached_index
	Decorator class for wrapping indexes with a cache. More...

class	chunk
	Represents a portion of a disk_index's postings file. More...

class	chunk_handler
	An interface for writing and merging inverted chunks of postings_data for a disk_index. More...

class	dirichlet_prior
	Implements Bayesian smoothing with a Dirichlet prior. More...

class	disk_index
	Holds generic data structures and functions that inverted_index and forward_index both use. More...

class	forward_index
	The forward_index stores information on a corpus by doc_ids. More...

class	inverted_index
	The inverted_index class stores information on a corpus indexed by term_ids. More...

class	ir_eval
	Evaluates lists of ranked documents returned from a search engine; can give stats per-query (e.g. More...

class	jelinek_mercer
	Implements the Jelinek-Mercer smoothed ranking model. More...

class	language_model_ranker
	Scores documents according to one of three different smoothed language model scoring methods described in "A Study of Smoothing Methods for Language Models Applied to Ad Hoc Information Retrieval" by Zhai and Lafferty, 2001. More...

class	okapi_bm25
	The Okapi BM25 scoring function. More...

class	pivoted_length
	The pivoted document length normalization ranking function. More...

class	postings_data
	A class to represent the per-PrimaryKey data in an index's postings file. More...

class	ranker
	A ranker scores a query against all the documents in an inverted index, returning a list of documents sorted by relevance. More...

class	ranker_factory
	Factory that is responsible for creating rankers from configuration files. More...

struct	score_data
	A score_data object contains information needed to evaluate a ranking function. More...

class	string_list
	A class designed for reading large lists of strings that have been persisted to disk. More...

class	string_list_writer
	A class for writing large lists of strings to disk with an associated index file for fast random access. More...

class	vocabulary_map
	A read-only view of a B+-tree-like structure that stores the vocabulary for an index. More...

class	vocabulary_map_writer
	A class that writes the B+-tree-like data structure used for storing the term id mapping in an index. More...

Typedefs
using	dblru_inverted_index = cached_index< inverted_index, caching::default_dblru_cache >
	Inverted index using default DBLRU cache.

using	splay_inverted_index = cached_index< inverted_index, caching::splay_cache >
	Inverted index using splay cache.

using	memory_forward_index = cached_index< forward_index, caching::no_evict_cache >
	In-memory forward index.

using	dblru_forward_index = cached_index< forward_index, caching::default_dblru_cache >
	Forward index using default DBLRU cache.

using	splay_forward_index = cached_index< forward_index, caching::splay_cache >
	Forward index using splay cache.

Enumerations
enum	index_file { DOC_IDS_MAPPING = 0, DOC_IDS_MAPPING_INDEX, DOC_SIZES, DOC_LABELS, DOC_UNIQUETERMS, LABEL_IDS_MAPPING, POSTINGS, TERM_IDS_MAPPING, TERM_IDS_MAPPING_INVERSE }
	Collection of all the files that comprise a disk_index.

Functions
template<class Index , class... Args>
std::shared_ptr< Index >	make_index (const std::string &config_file, Args &&...args)
	Factory method for creating indexes. More...

template<class Index , template< class, class > class Cache, class... Args>
std::shared_ptr< cached_index< Index, Cache > >	make_index (const std::string &config_file, Args &&...args)
	Factory method for creating indexes that are cached. More...

template<class PrimaryKey , class SecondaryKey >
io::compressed_file_reader &	operator>> (io::compressed_file_reader &in, postings_data< PrimaryKey, SecondaryKey > &pd)
	Reads semi-compressed postings data from a compressed file. More...

template<>
io::compressed_file_reader &	operator>> (io::compressed_file_reader &in, postings_data< std::string, doc_id > &pd)
	Reads semi-compressed postings data from a compressed file. More...

template<class PrimaryKey , class SecondaryKey >
bool	operator== (const postings_data< PrimaryKey, SecondaryKey > &lhs, const postings_data< PrimaryKey, SecondaryKey > &rhs)

template<>
std::unique_ptr< ranker >	make_ranker< absolute_discount > (const cpptoml::table &)
	Specialization of the factory method used to create absolute_discount rankers.

template<>
std::unique_ptr< ranker >	make_ranker< dirichlet_prior > (const cpptoml::table &)
	Specialization of the factory method used to create dirichlet_prior rankers.

template<>
std::unique_ptr< ranker >	make_ranker< jelinek_mercer > (const cpptoml::table &)
	Specialization of the factory method used to create jelinek_mercer rankers.

template<>
std::unique_ptr< ranker >	make_ranker< okapi_bm25 > (const cpptoml::table &)
	Specialization of the factory method used to create okapi_bm25 rankers.

template<>
std::unique_ptr< ranker >	make_ranker< pivoted_length > (const cpptoml::table &)
	Specialization of the factory method used to create pivoted_length rankers.

std::unique_ptr< ranker >	make_ranker (const cpptoml::table &)
	Convenience method for creating a ranker using the factory. More...

template<class Ranker >
void	register_ranker ()
	Registration method for rankers. More...

Detailed Description

Indexes to create efficient representations of data.

Function Documentation

template<class Index , class... Args>

std::shared_ptr<Index> meta::index::make_index	(	const std::string &	config_file,
		Args &&...	args
	)

Factory method for creating indexes.

inverted_index is a friend of the factory method used to create cached versions of it.

forward_index is a friend of the factory method used to create cached versions of it.

forward_index is a friend of the factory method used to create it.

Usage:

auto idx = index::make_index<derived_index_type>(config_path);

Parameters

config_file	The path to the configuration file to be used to build the index
args	any additional arguments to forward to the constructor for the chosen index type (usually none)

Returns: A properly initialized index

template<class Index , template< class, class > class Cache, class... Args>

std::shared_ptr<cached_index<Index, Cache> > meta::index::make_index	(	const std::string &	config_file,
		Args &&...	args
	)

Factory method for creating indexes that are cached.

inverted_index is a friend of the factory method used to create cached versions of it.

forward_index is a friend of the factory method used to create cached versions of it.

forward_index is a friend of the factory method used to create it.

Usage:

auto idx =
    index::make_index<dervied_index_type,
                      cache_type>(config_path, other, options);

Other options will be forwarded to the constructor for the chosen cache class.

Parameters

config_file	the path to the configuration file to be used to build the index.
args	any additional arguments to forward to the constructor for the cache class chosen

Returns: A properly initialized, and automatically cached, index.

template<class PrimaryKey , class SecondaryKey >

io::compressed_file_reader & meta::index::operator>>	(	io::compressed_file_reader &	in,
		postings_data< PrimaryKey, SecondaryKey > &	pd
	)

Reads semi-compressed postings data from a compressed file.

Parameters

in	The stream to read from
pd	The postings data object to write the stream info to

Returns: the input stream

template<>

io::compressed_file_reader& meta::index::operator>>	(	io::compressed_file_reader &	in,
		postings_data< std::string, doc_id > &	pd
	)

inline

Reads semi-compressed postings data from a compressed file.

Parameters

in	The stream to read from
pd	The postings data object to write the stream info to

Returns: the input stream

template<class PrimaryKey , class SecondaryKey >

bool meta::index::operator==	(	const postings_data< PrimaryKey, SecondaryKey > &	lhs,
		const postings_data< PrimaryKey, SecondaryKey > &	rhs
	)

Parameters

lhs	The first postings_data
rhs	The postings_data to compare with

Returns: whether this postings_data has the same PrimaryKey as the paramter

std::unique_ptr< ranker > meta::index::make_ranker ( const cpptoml::table & config )

Convenience method for creating a ranker using the factory.

Factory method for creating a ranker.

This should be specialized if your given ranker requires special construction behavior (e.g., reading parameters).

template<class Ranker >

void meta::index::register_ranker ( )

Registration method for rankers.

Clients should use this method to register any new rankers they write.

Classes

Typedefs

Enumerations

Functions

Detailed Description

Function Documentation