Elevator Saga – An elevator programming game

http://play.elevatorsaga.com/

by sandebert • 12 years ago

411 104 12 years ago

play.elevatorsaga.com

zzleeper• 12 years ago

Nitpick: it breaks the browser's back button

bondezu• 12 years ago

Sure does

astrojetsonjr• 12 years ago

Yea, the super wide screen is super annoying. Is there some reason for the big width? A little stealth at work would be nice, hard to hide something that huge.

KeytarHero• 12 years ago

Another nitpick: it's 1360 px wide.

fnordfnordfnord• 12 years ago

Yeah, I just had a little difficulty with that. It doesn't fit on my crappy projector.

dsjoerg• 12 years ago

came to the comments to say this

Kiro• 12 years ago

This is built with Riot.

https://news.ycombinator.com/item?id=8928433

sntran• 12 years ago

v1. Not the same version as that HN article.

danvk3• 12 years ago

Slightly related question: are there any standard workloads and tools out there for experimenting with elevator programming?

My apartment building has a utility elevator and two normal elevators. Each floor has two sets of call buttons. These have been programmed in different ways over the years, and I've always been curious if there was a good way to quantify the changes.

eplanit• 12 years ago

http://www.quora.com/Is-there-any-public-elevator-scheduling...

chrissnell• 12 years ago

Elevator programming... anybody remember this commercial?

https://www.youtube.com/watch?v=B3rKBw5ZNL4

jazzychad• 12 years ago

This is incredible. I've been successfully nerd-sniped away from work. Also nice touch w/ the time-scale factors being Fibonacci numbers :) Great work.

jackmaney• 12 years ago

Likewise.

AceJohnny2• 12 years ago

This is awesome, however is there any way to get better syntax errors? Damnit Jim, I'm a C programmer not a Javascript coder!

danvk3• 12 years ago

Try looking in the dev tools? I've been able to debug a few runtime errors this way.

Brashman2• 12 years ago

I got to Challenge #5 by just having the elevators go to every floor like in the first example. It'd be nice to have an earlier challenge with only a single elevator force you to have a more complex controller. With 4 elevators going at a time, it's harder for me to "debug" and figure out how to use the API.

Someone1234• 12 years ago

I got to Challenge #5 by just having the elevators go to every floor like in the first example.

Strange, that strategy doesn't allow me to get past challenge 2 (just going to every floor one after the other).

Brashman2• 12 years ago

Guess, I got lucky, haha. I should probably go back to challenge 2 and learn how to program these then.

umutisik• 12 years ago

This is brilliant. Do you know of other games like this?

petercooper• 12 years ago

Arguably https://www.bloc.io/ruby-warrior (warning: sound autoplays) - although there's something direct and storyless about the elevator one that I prefer.

jacinda• 12 years ago

http://www.pythonchallenge.com/ - Gamified way to learn Python, but is a puzzle in addition to being a game. Is not exclusive to Python, but many things are intended to be solved with things that are idiomatic in Python.

www.checkio.org - Looks more like a game, but the programming environment feels more "in-your-face" than elevator saga to me.

Timothee• 12 years ago

This one was on HN a few months ago: https://alexnisnevich.github.io/untrusted/

clarkmoody• 12 years ago

A project during my graduate work was to solve this problem. You can read my write up, which includes pseudo-code for the best algorithm I found[1].

Long story short: a simple, rules-based algorithm defeated my best efforts at having multiple elevators working together to coordinate their action.

[1] https://clarkmoody.com/Moody_AgentBasedElevatorControl.pdf

Fede_V• 12 years ago

I was horrendously worried this would be a parody of the incident with Rebecca Watson. I'm glad this is much more tasteful - looks really, really fun actually.

chipuni• 12 years ago

In challenge 3, I got the following error:

There is a problem with your code: .init@http://play.elevatorsaga.com/app.js line 66 > eval:12:9 createWorldController/controller.start@http://play.elevatorsaga.com/world.js:185:13 app.startChallenge@http://play.elevatorsaga.com/app.js:175:9 @http://play.elevatorsaga.com/app.js:216:13 riot.observable/el.trigger@http://play.elevatorsaga.com/libs/riot.js:45:1 pop@http://play.elevatorsaga.com/libs/riot.js:89:31

rco8786• 12 years ago

The error messages are bad because eval()...but rest assured there is a problem in your code.

Scaevolus• 12 years ago

If you accidentally make an infinite loop, you can no longer load the page :(

scott_karana• 12 years ago

Good find!

Clearing cookies/localstorage should fix that for you, at least until the devs figure out a fix :)

tokenizerrr2• 12 years ago

Very fun game. After playing for a while I did of course look for a way to break it.

{ init: function(elevators, floors) { console.log(window.world); }, update: function(dt, elevators, floors) { _.each(window.world.users, function(user) { if(user.done) { user.removeMe = true; user.trigger("removed"); user.off("*"); }else{ user.done = true; user.trigger("exited_elevator", 0); } }) } }

justforonce• 12 years ago

lol

sandsand• 12 years ago

How do I store global state (if at all)?

danvk3• 12 years ago

It's JavaScript, everything is a global! (so long as you don't declare it with var)

noonespecial2• 12 years ago

Wow. I want so many more of these kind of things for my kids. It's so close to using code to solve real problems. How about an assembly line version where many parts have to come together in the correct order? Or an air traffic control one? Subway scheduling? Pizza delivery? More please!

wickawic• 12 years ago

It isn't quite programming, but your assembly line comment reminded me of http://pleasingfungus.com/Manufactoria/ which is a game about making state automata.

magwo5• 12 years ago

Yeah! Something I think about occasionally is traffic-light optimization problems, optimizing for throughput, wait-time, safety etc. I think it could work well in a packaging similar to Elevator Saga.

EchoAce• 12 years ago

Accessibility to non-programmers though as a good and inspiring learning tool? Or is that not an intended purpose?

Gustomaximus• 12 years ago

Non-programmer here playing. It gamifies coding for sure. Intended purpose unknown.

If the makers read this, firstly this is brilliant. Second my feature request would be to have some record of history to watch how I improve (or not) each simulation.

noonespecial2• 12 years ago

Nitpick. Accidentally programming an infinite loop kills the page. Refreshing restores the offending code and immediately does it again. Had to clear cookies to get going again?

Just drop in a while (1) {} to reproduce.

kalleboo• 12 years ago

Slightly related - SimTower was originally created as an elevator simulator - if you right click on an elevator engine room in the game you get a wealth of programming options

sneak• 12 years ago

mind: blown

giancarlostoro• 12 years ago

Never even knew all those years playing SimTower... I knew other tricks, but never this.

aidenn0• 12 years ago

The people in that game were a lot smarter though; if the only path to a floor required switching elevators, they would do it.

sukilot• 11 years ago

Well Sim tower had range limit elevators. This game doesn't.

techdragon• 12 years ago

Damn I miss this game

sossles• 12 years ago

Pretty cool concept. Had a little trouble working out how to get started because on my 1024px wide monitor, the 'apply' button was not visible.

function_seven2• 12 years ago

Need help on this. I tried registering a handler for the up_button_pressed and down_button_pressed events, but the handler doesn't seem to be passed any arguments.

Is this correct?

    floor.on("up_button_pressed", function(event) { ... } );

tokenizerrr2• 12 years ago

I don't think you need an argument. Within the callback function you still hold a reference to floor, and you know the up button has been pressed. There doesn't seem to be any more information. Note that there is also down_button_pressed

SeoxyS3• 12 years ago

My attempt at a basic smart algorithm. Not so easy...

https://gist.github.com/kballenegger/e275a99d50de2ee07f97

idbehold• 12 years ago

Why do you have conditionals written like this: if (elevator.goingUpIndicator() == true)? Why not just: if (elevator.goingUpIndicator())?

_lce05• 12 years ago

I believe some people really need think in term of comparations and, for those, adding a "==" symbol make sense, even if the resultant code doesn't make any sense at all!!

Also, I can never understand why people write ..

    if (foo()) {
        return true;
    } else {
        return false;
    }

.. or things like extra parens on conditionals, or weird styles like:

    return (false);

I strongly believe people write as they talk, and talk as they think; which not clearly translates linearly when what you write is code ;)

_lce05• 12 years ago

here mine: https://gist.github.com/eridal/7ce55190837801811067

side note: why are you using underscore? I wanted to try your code, but doesn't work out-of-the-box.

SeoxyS3• 12 years ago

LoDash actually, not Underscore. Mostly because it's included by the game already. The code should run as-is. That said, it does occasionally get stuck. I think I have a bug with the direction indicators.

eru4• 12 years ago

I wonder how much more efficient you could be, if people didn't just call for going up/down, but their destination floor.

_lce05• 12 years ago

ahead of time optimization!

g8gggu89• 12 years ago

They have that at work and it takes far longer to get an elevator. It's always annoying going to those buildings and using those elevators.

eru4• 12 years ago

I like it much more. Yes, getting an elevator might take longer, but total travel time should be reduced. (Otherwise, the system is programmed wrong.)

nness• 12 years ago

In more than a few buildings I've worked in, these 'destination controlled' elevators shine the moment after a fire-drill and a couple of hundred people attempt to get back upstairs. It must be quicker, how else to justify what I'd imagine to be a far higher cost of operation.

tfinniga• 12 years ago

I'd love to see a version of the game that does this, for comparison.

frevd2• 12 years ago

// works well enough:

{ currentFloor: 0,

    init: function(elevators, floors) {
        var elevator = elevators[0]; // Let's use the first elevator
        elevator.on("idle", function() {
            // The elevator is idle, so let's go to all the floors (or did we forget one?)
            var nextFloor; 
            do nextFloor = Math.round(Math.random() * 2); while (nextFloor == this.currentFloor); 
            elevator.goToFloor(this.currentFloor = nextFloor);
        });
    },
    update: function(dt, elevators, floors) {
        // We normally don't need to do anything here
    }, 
    vendor: 'Sirius Cybernetics Corporation'
}

frevd2• 12 years ago

Okay, didn't read or look (currentFloor is already defined) and this won't work in this context.

Here is another approach that brought me through till challenge #7:

    {   
        init: function(elevators, floors)  // hook up events
        {
            // these are the global wish lists that idle elevators choose from (key are floor numbers, values are number of people): 
            var wishListUp = {}, wishListDown = {}; 

            for (var i = 0, l = elevators.length; i < l; i++)
            {
                var elevator = elevators[i];
                // API: goToFloor(n) [enqueues], stop() [clears queue], currentFloor(), 
                //      goingUpIndicator([set]), goingDownIndicator([set]), loadFactor() [0..1], 
                //      destinationQueue[], checkDestinationQueue() [after manual update]

                elevator.on("idle", function()  // elevator destination queue finished
                {
                    processWishList();
                }); 

                elevator.on("floor_button_pressed", function(floorNum)  // passenger indicates where to go
                {
                    if (this.destinationQueue.filter(function (d) { return d == floorNum; }).length == 0)  // if not already enqueued
                        this.goToFloor(floorNum);  // enqueue
                    // note: passengers coming first need to be delivered first (or at least at all)
                    //       however, the elevator will check by passing, whether one destination
                    //       can be approached before the others since it comes on the way. 
                }); 

                elevator.on("passing_floor", function(floorNum, direction/*"up"/"down"*/)  // if not in destination queue
                {
                    updateIndicators(this);  // indicate next destination from here
                    // we stop here if the queue contains this destination, 
                    // or if a passenger on the global wish list want to go in our direction. 
                    // we can only hope that people check where the elevator is going. 
                    if (this.destinationQueue.filter(function(d) { return d == floorNum; }).length > 0)
                    {
                        this.destinationQueue = this.destinationQueue.filter(function(d) { return d != floorNum; });  // remove from later
                        this.destinationQueue.unshift(floorNum);  // add as immediate next destination
                        this.checkDestinationQueue();  // announce modification
                    }
                    else if (this.loadFactor() < 1.0)  // if there is some space left
                    {
                        switch (getDirection(this))
                        {
                            case 1:  // going up
                                if (wishListUp[floorNum])  // are people waiting to go up from here?
                                {
                                    //if ((1.0 - this.loadFactor()) * 10.0 - wishListUp[floorNum] > 0)  // assume capacity for 10 people with regular weight
                                    //    delete wishListUp[floorNum];  // mark as visited
                                    this.destinationQueue.unshift(floorNum);  // add as immediate next destination
                                    this.checkDestinationQueue();  // announce modification
                                }
                                break;
                            case -1: // going down
                                if (wishListDown[floorNum])  // are people waiting to go down from here?
                                {
                                    //if ((1.0 - this.loadFactor()) * 10.0 - wishListDown[floorNum] > 0)  // assume capacity for 10 people with regular weight
                                    //    delete wishListDown[floorNum];  // mark as visited
                                    this.destinationQueue.unshift(floorNum);  // add as immediate next destination
                                    this.checkDestinationQueue();  // announce modification
                                }
                                break;
                            case 0:  // final destination
                            default: 
                                break; 
                        }
                    }
                }); 

                elevator.on("stopped_at_floor", function(floorNum)  // one destination reached
                {
                    processWishList(); 
                    updateIndicators(this);  // next direction
                });
            }

            for (var i = 0, l = floors.length; i < l; i++)
            {
                var floor = floors[i];
                // API: floorNum()

                floor.on("up_button_pressed", function()  // somebody wants to go up from a certain floor
                {
                    // elevators are choosing their next best destination, 
                    // we just enqueue this into the global wish list queue: 
                    var f = this.floorNum(); 
                    if (wishListUp[f])
                        wishListUp[f]++; 
                    else
                        wishListUp[f] = 1;
                    processWishList(); 
                }); 

                floor.on("down_button_pressed", function()  // somebody wants to go down from a certain floor
                {
                    // elevators are choosing their next best destination, 
                    // we just enqueue this into the global wish list queue: 
                    var f = this.floorNum();
                    if (wishListDown[f])
                        wishListDown[f]++;
                    else
                        wishListDown[f] = 1;
                    processWishList();
                });
            }


            function processWishList()  // give idle elevators a new destination
            {
                for (var i = 0, l = elevators.length; i < l; i++)  // idle
                {
                    var elevator = elevators[i]; 
                    if (elevator.destinationQueue.length == 0)
                    {
                        var next = chooseFloor(elevator.currentFloor(), true);  // find closest wish
                        if (elevator.currentFloor() != next)
                            elevator.goToFloor(next); 
                    }
                }
            }

            function getDirection(elevator)
            {
                if (elevator.destinationQueue.length == 0)
                    return 0;  // nowhere
                else if (elevator.currentFloor() < elevator.destinationQueue[0])
                    return 1;  // up
                else
                    return -1;  // down
            }

            function chooseFloor(currentFloor, dequeue)
            {
                // choose next destination from the global wish lists for up and down, 
                // depending on a) closest distance and b) number of waiting passengers: 
                var wishList = {};  // joined up and down lists with passenger counts
                var floors = [];  // array of distinct floor numbers
                for (var i in wishListUp)
                {
                    wishList[i] = wishListUp[i]; 
                    floors.push(i); 
                }
                for (var i in wishListDown)
                    if (wishList[i])
                        wishList[i] += wishListDown[i];
                    else
                    {
                        wishList[i] = wishListDown[i];
                        floors.push(i); 
                    }
                floors.sort(function(a, b)
                    { 
                        var res = Math.abs(currentFloor - a) - Math.abs(currentFloor - b);  // by closeness asc
                        if (res == 0)
                            res = wishList[b] - wishList[a];  // by passengers waiting desc
                        return res; 
                    }); 
                if (floors.length == 0)
                    return 0;  // nothing to do, go back to base
                var next = floors[0];
                if (dequeue)
                {
                    if (wishListUp[next])
                        delete wishListUp[next]; 
                    if (wishListDown[next])
                        delete wishListDown[next];
                }
                return next; 
            }

            function updateIndicators(elevator)
            {
    return;  // there seems to be a bug if announcing, people do not react ..
                switch (getDirection(elevator))
                {
                    case 1:  // up
                        if (!elevator.goingUpIndicator())
                            elevator.goingUpIndicator(true);
                        if (elevator.goingDownIndicator())
                            elevator.goingDownIndicator(false);
                        break; 

                    case -1:  // down
                        if (elevator.goingUpIndicator())
                            elevator.goingUpIndicator(false);
                        if (!elevator.goingDownIndicator())
                            elevator.goingDownIndicator(true);
                        break; 

                    case 0:  // nowhere
                    default: 
                        if (elevator.goingUpIndicator())
                            elevator.goingUpIndicator(false);
                        if (elevator.goingDownIndicator())
                            elevator.goingDownIndicator(false);
                        break; 
                }
            }
        },

        update: function(time, elevators, floors)  // loop during operation, called each frame
        {
        }, 

        vendor: 'frevd'
    }

benwaffle• 12 years ago

  {init:function(){world.transportedCounter=999999},update:eval}

_lce05• 12 years ago

oh man, both clever and evil. love it!

Daneel_• 12 years ago

For someone like me who knows zero Javascript, this is exactly the sort of puzzle I need to get started. Elevator programming has always interested me. Thanks also to SeoxyS for posting some code - I was struggling a lot to get started without a few examples.

chidevguy• 12 years ago

Here's a fairly simple strategy for beating challenges 1 - 5. Basically drop off people in the elevator according to whoever's floor is closest. Then once the elevator is empty go to the closest floor that has people waiting to be picked up.

https://gist.github.com/cspags/93f18a2fe505bf4f1686

bgun• 12 years ago

Cleverly done! And "Saga" got a chuckle from me.

Aeolun• 12 years ago

This is awesome

q_no2• 12 years ago

Is it just me, or is programming more than one elevator buggy?

I used a for( var i =0;i < elevators.length;++i) statement to apply my code to each elevator, but people only keep using the last one. Could someone give me a hint? ;)

archgoon• 12 years ago

You're probably hitting an issue with the way that closures work in javascript (and many other languages).

    for(var i = 0; i < elevators.length; ++i) {
        elevator[i].on("floor_button_pressed",
             function(floorNum){ elevator[i].goToFloor(floornum)});
    }

Doesn't do what one might expect. When the anonymous function is invoked, it looks up the value of the 'i' identifier, which will have changed it's value to elevators.length by the end of the loop. To get the behavior you want, I've seen people do

    for(var i = 0; i < elevators.length; ++i) {
        (function(i){
            elevator[i].on("floor_button_pressed",
                function(floorNum){ elevator[i].goToFloor(floornum)});
        })(i);
    }

This creates a new scope, which ensures that 'i' has the value that was passed in. I'm afraid I'm a little too tired to look up the parts of the spec that make the semantics clear.

q_no2• 12 years ago

Thank you! Your suggestion makes sense indeed and works fine!

indutny• 12 years ago

Posted a solution: https://github.com/magwo/elevatorsaga/wiki/Solution-by-indut...

Ideka• 12 years ago

A couple of problems with the API.

First, why do you have to call checkDestinationQueue after modifying the queue? It's awfully redundant. I assume this is due to some kind of limitation.

And second, goingUpIndicator and goingDownIndicator are kind of sketchy. Can you activate both at the same time? What effect would that have? There should be a single property, directionIndicator of an enum type with the possible values up, down, and none. I don't think you can make enums in javascript though, but I don't know the language very well. I'm just explaining this in terms that I know; there probably is a suitable javascript equivalent or replacement.

Bdiem• 12 years ago

I'm not a developer of the game but:

DestinationQueue handling: It is not redundant, those are different options. Just to give an valid example: Add something to the queue, sort the queue, make the elevator run the updated and sorted queue.

Having both goingUpIndicator and goingDownIndicator is probabaly necessary to get this abritrary third state (both enabled / both disabled) which essentially indicates that the elevator will go in both directions.

magwo5• 12 years ago

Yeah this is basically correct. There is nothing really preventing an elevator from reporting that it's going both up and down. The up/down indicators are used for two things: 1. To shut off the up/down request indicators correctly on the floor when the elevator arrives. 2. By passengers to decide whether to get on an elevator or not.

avereveard2• 12 years ago

correct, those works as flag with 'accept passenger in these direction' meaning. also note that if you change those values while you are at a floor, you need to go to that floor again for passenger to notice.

tempodox• 12 years ago

WTF???

outsidetheparty• 12 years ago

I stopped writing javascript for work at 10pm and then for fun immediately started writing javascript for imaginary elevators until way too late o'clock

I can't help but feel like there is something deeply wrong with me

NietTim• 12 years ago

Now this is cool. Thanks for sharing, I will be playing this for a bit over the weekend :)

highmastdon• 12 years ago

Added solution: https://github.com/magwo/elevatorsaga/wiki/Solution-by-alber...

Can work for all up to 9, except 5. Can't get it to work. When it has to be done within 'x' moves, change foreach 'e' variable to var `e = <total elevator minus 1>`

Main 'pattern' behind it: the elevators decide everything. Each elevator does the same based on a global array of where passengers are waiting.

joelthelion• 12 years ago

How are the passengers generated? Do they follow a realistic distribution, or are they just completely random?

The game would be a lot more fun with realistic or even real measured workloads.

magwo5• 12 years ago

Dev here. :)

They spawn at a fixed rate, but at random floors, with 50% spawning at the bottom floor.

I agree it would be more interesting if there were patterns, distributions, more popular floors etc. Haven't gotten around to implementing it. There's a small unused bit of code here intended for this: https://github.com/magwo/elevatorsaga/blob/master/challenges...

pepijndevos• 12 years ago

I think it would be a lot easier if idle elevators have idle fire every time someone presses a button.

That way the elevator can evaluate the new situation. Now you have to look up an elevator in the button event, and the API does not specify many properties, only events.

magwo5• 12 years ago

Developer here! Thanks for all the feedback. Appreciate all of it, including bug reports! Pull requests also welcome.

Especially I would appreciate help with adding more challenges, and/or making them all balanced and interesting, for a good and reasonable difficulty curve.

It is very simple to tweak them - they are defined at the bottom of challenges.js: https://github.com/magwo/elevatorsaga/blob/master/challenges...

christiangenco• 12 years ago

What I would've loved to have seen in some of the later levels is a very clear "you now need to use this new API call to accomplish the goal. Here's how that call works."

For example: in level 2, what if people only ever came to the second floor trying to go to the third floor, so you had to look at where buttons were being pushed and where they wanted to go?

avereveard2• 12 years ago

hi, why leaving the elevator at a floor doesn't pick up additional passengers? i.e.

http://pastebin.com/xA4NJbas @ http://play.elevatorsaga.com/#challenge=2

(yes that's only a stub, but has logging as I was trying to understand the event order)

at least elevator.goToFloor(elevator.currentFloor());

doesn't count as a move and unlocks the passenger to onboarding

btw, when you start you get 2 moves per elevator in the moves count

magwo5• 11 years ago

The last one about moves has been fixed.

The additional-people-not-getting-on is kind of an architectural problem with the game, working on it.

joefreeman• 12 years ago

This is cool. I had a similar idea in mind when I started working on my elevator project [1], but got a bit distracted with supporting multiple buildings.

[1] https://rawgit.com/joefreeman/elevator/master/index.html

rahulroy9202• 12 years ago

loved it.

demarq• 12 years ago

Couldn't get past eight, but what a fun idea!!

As an extra challenge I followed these rules:

1) Elevators cannot inspect the state of other elevators

2) No Hacking the games internal apis

3) No timeout callbacks

tasuki• 12 years ago

Markus Mattinen submitted the best solution so far: https://github.com/MarkusMattinen/elevatorsaga-solutions/blo...

And here's my solution, not too bad, had lots of fun: https://github.com/tasuk/elevatorsaga-solver