EMA For go

package main

import (
	"fmt"
	"math"
	"time"
)

// fdtime is time period for a execution time sampling
// ftime shows how fast it reacts on changes.
//
func MovingExpAvg(value, oldValue, fdtime, ftime time.Duration) time.Duration {
	alpha := 1.0 - math.Exp(-fdtime.Seconds()/ftime.Seconds())
	r := alpha*value.Seconds() + (1.0-alpha)*oldValue.Seconds()
	return time.Duration(time.Duration(r) * time.Second)
}

func main() {
	type execution struct {
		duration time.Duration
		delta    time.Duration
	}

	executionTimes := []execution{
		execution{time.Duration(10 * time.Minute), time.Duration(time.Minute)},
		execution{time.Duration(12 * time.Minute), time.Duration(5 *time.Minute)},
		execution{time.Duration(11 * time.Minute), time.Duration(10*time.Minute)},
		execution{time.Duration(15 * time.Minute), time.Duration(time.Minute)},
		execution{time.Duration(10 * time.Minute), time.Duration(time.Minute)},
		execution{time.Duration(10 * time.Minute), time.Duration(time.Minute)},
	}

	v1 := time.Duration(10 * time.Minute) // initial value
	v2 := time.Duration(10 * time.Minute) // initial value
	v3 := time.Duration(10 * time.Minute) // initial value

	ftime1 := time.Duration(5 * time.Second)
	ftime2 := time.Duration(50 * time.Second)
	ftime3 := time.Duration(500 * time.Second)

	for _, measurement := range executionTimes {
		v1 = MovingExpAvg(measurement.duration, v1, measurement.delta, ftime1)
		v2 = MovingExpAvg(measurement.duration, v2, measurement.delta, ftime2)
		v3 = MovingExpAvg(measurement.duration, v3, measurement.delta, ftime3)

		fmt.Printf("%v %v %.v %v\n", measurement.duration, v1, v2, v3)
	}
	
	// Now a very greedy task which we wish to penalize
		executionTimes = []execution{
		execution{time.Duration(20 * time.Minute), time.Duration(2 *time.Minute)},
		execution{time.Duration(22 * time.Minute), time.Duration(10 *time.Minute)},
		execution{time.Duration(21 * time.Minute), time.Duration(20*time.Minute)},
		execution{time.Duration(25 * time.Minute), time.Duration(2*time.Minute)},
		execution{time.Duration(20 * time.Minute), time.Duration(2*time.Minute)},
		execution{time.Duration(20 * time.Minute), time.Duration(2*time.Minute)},
	}

	v1 = time.Duration(10 * time.Minute) // initial value
	v2 = time.Duration(10 * time.Minute) // initial value
	v3 = time.Duration(10 * time.Minute) // initial value

	for _, measurement := range executionTimes {
		v1 = MovingExpAvg(measurement.duration, v1, measurement.delta, ftime1)
		v2 = MovingExpAvg(measurement.duration, v2, measurement.delta, ftime2)
		v3 = MovingExpAvg(measurement.duration, v3, measurement.delta, ftime3)

		fmt.Printf("%v %v %.v %v\n", measurement.duration, v1, v2, v3)
	}
}