SimGo

SimGo is a discrete event simulation framework for Go. It is similar to SimPy and aims to be easy to set up and use.

Processes are defined as simple functions receiving simgo.Process as their first argument. Each process is executed in a separate goroutine, but it is guaranteed that only one process is executed at a time. For examples, look into the _examples folder.

Basic example: parallel clocks

A short example simulating two clocks ticking in different time intervals:

package main

import (
    "fmt"

    "github.com/fschuetz04/simgo"
)

func clock(proc simgo.Process, name string, delay float64) {
    for {
        fmt.Println(name, proc.Now())
        proc.Wait(proc.Timeout(delay))
    }
}

func main() {
    sim := simgo.NewSimulation()

    sim.ProcessReflect(clock, "slow", 2)
    sim.ProcessReflect(clock, "fast", 1)

    sim.RunUntil(5)
}

When run, the following output is generated:

slow 0
fast 0
fast 1
slow 2
fast 2
fast 3
slow 4
fast 4

Process communication example: ping pong

A more advanced example demonstrating how processes can communicate through events:

package main

import (
    "fmt"

    "github.com/fschuetz04/simgo"
)

type PingPongEvent struct {
    *simgo.Event
    otherEv *PingPongEvent
}

func party(proc simgo.Process, name string, ev *PingPongEvent, delay float64) {
    for {
        proc.Wait(ev)
        fmt.Printf("[%.0f] %s\n", proc.Now(), name)
        theirEv := ev.otherEv
        ev = &PingPongEvent{Event: proc.Event()}
        theirEv.otherEv = ev
        theirEv.TriggerDelayed(delay)
    }
}

func main() {
    sim := simgo.NewSimulation()

    pongEv := &PingPongEvent{Event: sim.Event(), otherEv: nil}
    pingEv := &PingPongEvent{Event: sim.Timeout(0), otherEv: pongEv}

    sim.ProcessReflect(party, "ping", pingEv, 1)
    sim.ProcessReflect(party, "pong", pongEv, 2)

    sim.RunUntil(8)
}

When run, this produces:

[0] ping
[1] pong
[3] ping
[4] pong
[6] ping
[7] pong

This example shows two processes communicating through events. Each process waits for its event to be triggered, prints its name and the current time, then triggers the event of the other process after a delay.

License

Licensed under the MIT License. See the licence file for details.