avgcounter

README

avgcounter

Package avgcounter implements a simple EMA (Exponential Moving Average) counter. The counter holds the exponentially (by time) weighted average of all added values.

See documentation and examples at pkg.go.dev

Documentation

Overview

Package avgcounter implements a simple EMA (Exponential Moving Average) counter. The New function creates a counter with the only parameter: avgInterval. Every Add call adds the value to the counter. The current value can be obtained using the Value method.

The counter holds the exponentially (by time) weighted average of all added values.

Example

counter := New(time.Minute)
counter.Add(42)

// We use special function in the test to emulate time passing. You don't
// need to do that, just let time fly.
passTime(time.Minute)

// The result is 42 * exp(-1)
fmt.Println(counter.Value())

Output:

15.450936529200579

Example (Multi_add)

counter := New(time.Minute)

for i := 0; i < 600; i++ {
	counter.Add(1)
	passTime(time.Second)
}

// The result about 60 (60 adds/minute)
fmt.Println(counter.Value())

Output:

59.49868752358285

Index

• type Counter
  • func New(avgInterval time.Duration) *Counter
  • func (c *Counter) Add(v float64)
  • func (c *Counter) Value() float64
  • func (c *Counter) ValuePer(interval time.Duration) float64

Examples

• Package
• Package (Multi_add)
• Counter.Add
• Counter.Add (More)
• Counter.ValuePer
• New

Types

type Counter

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

Counter is an EMA (Exponential Moving Average) counter.

func New

func New(avgInterval time.Duration) *Counter

New creates a new Counter with the given avgInterval.

Example

counter := New(time.Minute)

fmt.Println(counter.Value())

Output:

0

func (*Counter) Add

func (c *Counter) Add(v float64)

Add adds a new value to the counter.

Example

counter := New(time.Minute)
counter.Add(42)

fmt.Println(counter.Value())

Output:

42

Example (More)

counter := New(time.Minute)
counter.Add(42)

passTime(2 * time.Minute)
counter.Add(42)

// The result is 42 + 42 * exp(-2)
fmt.Println(counter.Value())

Output:

47.68408189593774

func (*Counter) Value

func (c *Counter) Value() float64

Value returns the current value of the counter.

func (*Counter) ValuePer

func (c *Counter) ValuePer(interval time.Duration) float64

ValuePer returns the current value of the counter, normalized to the given interval. It is actually a Value() * interval / avgInterval.

Example

counter := New(time.Minute)
counter.Add(42)

// 42 per minute is the 0.7 per second
fmt.Println(counter.ValuePer(time.Second))

Output:

0.7