README
¶
go-trending
Trending algorithm based on the article Trending at Instagram. To detect trends an items current behavior is compared to its usual behavior. The more it differes the higher / lower the score. Items will start trending if the current usage is higher than its average usage. To avoid items quickly become non-trending again the scores are smoothed.
- Configurable and simple to use
- Use your own clock implementation, e.g. for testing or similar
- Use any time series implementation as backend that implements the TimeSeries interface
Details
Uses a time series for each item to keep track of its past behavior and get recent behavior with small granularity. Computes the Kullback-Leibler divergence between recent behavior and expected, i.e. past, bahavior. Then blends the current item score with its past decayed maximum score to get the final score.
Examples
Creating a default scorer
import "github.com/codesuki/go-trending"
...
scorer := trending.NewScorer()
Creating a customized scorer
Parameters
- Time series: is used for creating the backing
TimeSeriesobjects - Half-life: controls how long an item is trending after the activity went back to normal.
- Recent duration: controls how much data is used to compute the current state. If there is not much activity try looking at larger duration.
- Storage duration: controls how much historical data is used. Trends older than the storage duration won't have any effect on the computation. The time series in use should have at least as much storage duration as specified here.
import "github.com/codesuki/go-trending"
...
func NewTimeSeries(id string) TimeSeries {
// create time series that satisfies the TimeSeries interface
return timeSeries
}
...
scorer := trending.NewScorer(
WithTimeSeries(NewTimeSeries),
WithHalflife(time.Hour),
WithRecentDuration(time.Minute),
WithStorageDuration(7 * 24 * time.Hour),
)
Using the scorer
import "github.com/codesuki/go-trending"
...
scorer := trending.NewScorer()
scorer.AddEvent("id", time)
// add more events. maybe using an event stream.
...
trendingItems := scorer.Score()
Documentation
GoDoc is located here
License
go-trending is MIT licensed.
Documentation
¶
Index ¶
- type Option
- func WithCountThreshold(threshold float64) Option
- func WithHalfLife(halfLife time.Duration) Option
- func WithMaxResults(maxResults int) Option
- func WithRecentDuration(recentDuration time.Duration) Option
- func WithScoreThreshold(threshold float64) Option
- func WithSlidingWindow(creator SlidingWindowCreator) Option
- func WithStorageDuration(storageDuration time.Duration) Option
- func WithTimeSeries(creator TimeSeriesCreator) Option
- type Scorer
- type Scores
- type SlidingWindow
- type SlidingWindowCreator
- type TimeSeries
- type TimeSeriesCreator
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Option ¶
type Option func(*options)
func WithCountThreshold ¶
func WithHalfLife ¶
func WithMaxResults ¶
func WithRecentDuration ¶
func WithScoreThreshold ¶
func WithSlidingWindow ¶
func WithSlidingWindow(creator SlidingWindowCreator) Option
func WithStorageDuration ¶
func WithTimeSeries ¶
func WithTimeSeries(creator TimeSeriesCreator) Option
type SlidingWindow ¶
type SlidingWindowCreator ¶
type SlidingWindowCreator func(string) SlidingWindow
type TimeSeries ¶
type TimeSeries interface {
IncreaseAtTime(amount int, time time.Time)
Range(start, end time.Time) (float64, error)
}
func NewMemoryTimeSeries ¶
func NewMemoryTimeSeries(id string) TimeSeries
type TimeSeriesCreator ¶
type TimeSeriesCreator func(string) TimeSeries
Source Files
Directories