vw

package module
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 Go to latest Published: Oct 2, 2019 License: MIT Imports: 3 Imported by: 2

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go-vowpal-wabbit

Vowpal Wabbit bindings for Golang

import "github.com/orktes/go-vowpal-wabbit"

Usage

Library depends on the Vowpal Wabbit shared library. To install the shared lib please follow VW installation instruction.

API is designed to closely resemble the C API of Vowpal Wabbit with minor changes done to make it more convinient to be used from go. Library is not thread safe and additional locking is required if libary is being called from multiple goroutines.

Minimalistic example

import (
    wabbit "github.com/orktes/go-vowpal-wabbit"
)

func main() {
	vw, _ := wabbit.New("-q st --noconstant --quiet")
	defer vw.Finish()

	// Learn an example
	ex, _ := vw.ReadExample("1 |s p^the_man w^the w^man |t p^un_homme w^un w^homme")
	vw.Learn(ex)

	// Predict with features
	ex, _ = vw.ReadExample("|s p^the_man w^the w^man |t p^un_homme w^un w^homme")
	res := vw.Predict(ex)

	fmt.Printf("Prediction: %f", res)
	// Output: Prediction: 0.855723
}

TODO

  • Handle exceptions from VW
  • Add pooling for example creation (json & dsjson)

Documentation

Overview

Package vw implements golang bindings for Vowpal Wabbit Online Learning library. API is designed to closely resemble the C API of Vowpal Wabbit with minor changes done to make it more convinient to be used from go. Library is not thread safe and additional locking is required if libary is being called from multiple goroutines.

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Error 

type Error struct {
	// contains filtered or unexported fields
}

Error errors returned by vowpal wabbig functions

func (*Error) Error 

func (te *Error) Error() string

type Example 

type Example struct {
	// contains filtered or unexported fields
}

Example a single Vowpal Wabbit example

func (*Example) Finish 

func (ex *Example) Finish()

Finish finishes the example

func (*Example) GetAction 

func (ex *Example) GetAction(i int) int

GetAction returns the action for index

func (*Example) GetActionScore 

func (ex *Example) GetActionScore(i int) float32

GetActionScore returns action score for index

func (*Example) GetActionScoreLength 

func (ex *Example) GetActionScoreLength() int

GetActionScoreLength get action score length

func (*Example) GetActionScores 

func (ex *Example) GetActionScores() []float32

GetActionScores returns all action scores as a slice

func (*Example) GetActions 

func (ex *Example) GetActions() []int

GetActions returns all actions as a slice

func (*Example) GetConfidence 

func (ex *Example) GetConfidence(i int) float32

GetConfidence returns confidence

func (*Example) GetCostSensitivePrediction 

func (ex *Example) GetCostSensitivePrediction() float32

GetCostSensitivePrediction returns initial

func (*Example) GetFeatureNumber 

func (ex *Example) GetFeatureNumber() int

GetFeatureNumber returns number of features

func (*Example) GetImportance 

func (ex *Example) GetImportance() float32

GetImportance returns importance

func (*Example) GetInitial 

func (ex *Example) GetInitial() float32

GetInitial returns initial

func (*Example) GetLabel 

func (ex *Example) GetLabel() float32

GetLabel returns label

func (*Example) GetPrediction 

func (ex *Example) GetPrediction() float32

GetPrediction returns prediction

func (*Example) GetTag 

func (ex *Example) GetTag() string

GetTag returns tag

func (*Example) GetTagLength 

func (ex *Example) GetTagLength() int

GetTagLength returns tag length

func (*Example) GetTopicPrediction 

func (ex *Example) GetTopicPrediction(i int) float32

GetTopicPrediction returns topic prediction for index

type ExampleList 

type ExampleList []*Example

ExampleList a slice of examples

func (ExampleList) Finish 

func (el ExampleList) Finish()

Finish all examples in the list

type PerformanceStatistics 

type PerformanceStatistics struct {
	// Index of current pass
	CurrentPass uint64
	// The total number of features
	NumberOfFeatures uint64
	// Total number of examples
	NumberOfExamples uint64
	// The weighted sum of examples.
	WeightedExampleSum float64
	// The weighted sum of labels.
	WeightedLabelSum float64
	// The average loss since instance creation.
	AverageLoss float64
	// The best constant since instance creation.
	BestConstant float64
	// The best constant loss since instance creation.
	BestConstantLoss float64
}

PerformanceStatistics contains model performance stats

type VW 

type VW struct {
	// contains filtered or unexported fields
}

VW struct for a single Vowpal Wabbit model

Example 
vw, _ := New("-q st --noconstant --quiet")
defer vw.Finish()

// Learn an example
ex, _ := vw.ReadExample("1 |s p^the_man w^the w^man |t p^un_homme w^un w^homme")
vw.Learn(ex)

// Predict with features
ex, _ = vw.ReadExample("|s p^the_man w^the w^man |t p^un_homme w^un w^homme")
res := vw.Predict(ex)

fmt.Printf("Prediction: %f", res)

Output:
Prediction: 0.855723

func New 

func New(args string) (*VW, error)

New returns a new Vowpal Wabbit instance with given arguments

func NewWithModelData 

func NewWithModelData(args string, modelData []byte) (*VW, error)

NewWithModelData returns new Vowpal Wabbit instance with model data

func NewWithSeed 

func NewWithSeed(seedModel *VW, extraArgs string) (*VW, error)

NewWithSeed returns a new Vowpal Wabbit instance seeded with another model

func (*VW) CopyModelData 

func (vw *VW) CopyModelData() []byte

CopyModelData returns model data as a byte slice

func (*VW) EndOfPass 

func (vw *VW) EndOfPass() error

EndOfPass ends current pass and syncs metrics

func (*VW) EndParser 

func (vw *VW) EndParser() error

EndParser ends the parser

func (*VW) Finish 

func (vw *VW) Finish()

Finish stops VW (and, eg, write weights to disk)

func (*VW) FinishPasses 

func (vw *VW) FinishPasses() error

FinishPasses finalize passes

func (*VW) Learn 

func (vw *VW) Learn(ex *Example) float32

Learn learns a single example and returns the score

func (*VW) MultiLineLearn 

func (vw *VW) MultiLineLearn(exs []*Example) error

MultiLineLearn learns from a list of example and returns the score

func (*VW) MultiLinePredict 

func (vw *VW) MultiLinePredict(exs []*Example) error

MultiLinePredict predic using a list of examples

func (*VW) PerformanceStatistics 

func (vw *VW) PerformanceStatistics() (PerformanceStatistics, error)

PerformanceStatistics writes current performance stats

func (*VW) Predict 

func (vw *VW) Predict(ex *Example) float32

Predict returns a prediction using the example

func (*VW) PredictCostSensitive 

func (vw *VW) PredictCostSensitive(ex *Example) float32

PredictCostSensitive returns a cost sensitive prediction using the example

func (*VW) ReadDecisionServiceJSON 

func (vw *VW) ReadDecisionServiceJSON(json string) (ExampleList, error)

ReadDecisionServiceJSON reads examples from Decision Service JSON format

func (*VW) ReadDecisionServiceJSONFromBytes 

func (vw *VW) ReadDecisionServiceJSONFromBytes(json []byte) (ExampleList, error)

ReadDecisionServiceJSONFromBytes like ReadDecisionServiceJSON but takes in a byte slice (need to be null terminated)

func (*VW) ReadExample 

func (vw *VW) ReadExample(example string) (*Example, error)

ReadExample parses a single text based example

func (*VW) ReadJSON 

func (vw *VW) ReadJSON(json string) (ExampleList, error)

ReadJSON reads examples from format

func (*VW) SaveModel 

func (vw *VW) SaveModel()

SaveModel saves model to file given during construction

func (*VW) StartParser 

func (vw *VW) StartParser() error

StartParser starts the parser

func (*VW) SyncStats 

func (vw *VW) SyncStats() error

SyncStats syncs stats from the learner (should be called before vw.PerformanceStatistics)

Source Files

View all Source files

Directories

Path Synopsis
examples
contextual_bandit command
contextual_bandit_json command

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