You don't need a math PhD to play Dwarf Fortress, just to code it

https://the-stack-overflow-podcast.simplecast.com/episodes/you-dont-need-a-math-phd-to-play-dwarf-fortress-just-to-code-it/transcript

by robin_reala • 5 years ago

183 80 5 years ago

the-stack-overflow-podcast.simplecast.com

fridif4• 5 years ago

You don't need a math phd to code it either, you just need skill and motivation.

That might be correlated with having a phd, but it isn't mandatory.

EDIT: I physically cannot comprehend how what I have said is somehow worthy of a negative reaction.

chongli• 5 years ago

To code something like Dwarf Fortress takes an uncommon level of dedication. The project has been going for a decade and a half!

It's only recently that the project has been paying off via community funding/patronage. A great deal of those early years must have been very difficult for them.

_jal• 5 years ago

It's only recently that the project has been paying off via community funding/patronage.

Another way it is like a PhD - a ton of up-front work for an uncertain payoff, largely dependent on the whim of others.

bspammer• 5 years ago

I know it’s silly but for me the most impressive part of the whole project is that he doesn’t use version control. I can’t even comprehend how that’s possible.

hoten• 5 years ago

Certainly one of the most important shared attributes between getting a math PhD and working on the same game for 15 years is the stick-to-it-ness required.

cheesetable• 5 years ago

Headlines often aren't meant to be read literally.

It's just a teaser to read the article.

fridif4• 5 years ago

But why is it bad to react to a headline? It offered something interesting to consider.

MaxikCZ• 5 years ago

Headlines often aren't meant to be read literally.

Why is this normalized?

munk-a2• 5 years ago

I think it's arguable if you even need skill - I believe Toady One has mostly taught himself good project design through having to deal with Toady One's code from three years prior. Changing a fixed 2D legacy game to 3D and completely rewriting fluid dynamics in a shipped title will do that to you.

I agree entirely about motivation though - he's stuck with that project for an immense amount of time. Urist Borushdumat[1] and Boatmurdered[2] are both from 2007 - George W Bush was president then and The Colbert Report had barely gotten started - your nephew in high school was still in diapers. However - over the full run of nineteen years dwarf fortress has been in development[3] he has received pretty tremendous community support - well probably since 2005 or so - I don't know if anyone knew it existed in 2002.

1. http://www.bay12forums.com/smf/index.php?topic=15572.0

2. https://lparchive.org/Dwarf-Fortress-Boatmurdered/Introducti...

3. Wait - wtf - it's older than Firefly! (that's the show that made Nathan Fillion famous before Castle or Dr. Horrible's Sing-a-long-blog FYI) I can now use the line "I'm getting too old for this sh*"

bombcar• 5 years ago

And the number of times save compatibility has been broken is surprisingly small for a long-lived one-man project.

swayvil• 5 years ago

I'd say it just takes motivation. The skill comes through that.

Also, yr talking to a crew of whimsical fairy folk. Don't take the neg personally.

fridif4• 5 years ago

Appreciate this response :) Those who are actually out there building things are a bit too busy to pontificate here anymore

danblick• 5 years ago

I'd recommend thinking a little about the algorithms involved in efficiently assigning a nearby task to each dwarf and then planning a path for each dwarf to its destination.

It gets interesting pretty fast and a PhD would not hurt. :)

e.g. https://arxiv.org/abs/1906.08291

Would you maintain a roadmap telling you how to get from place to place, or just constantly replan? What happens when you change the available paths by building a wall or locking a door?

izend• 5 years ago

That's not even the most complex algorithm Tarn has implemented, I believe the ones he created for fluid dynamics are much more complex.

setr2• 5 years ago

Pathfinding is largely not that bad — hierarchal A* for long distance pathing, flow field for dense agent areas (eg your fort). With sufficient density, it’s worth recalculating the field repeatedly. Partitions can also be used for resource-lookup, threat caching, etc. Brogue’s djikstra maps[0], and Dave Mark’s modular influence maps[1] are very interesting possibilities as well..

Your paper is dealing with a completely different problem — collision avoidance is hard, and you really shouldn’t care about it in a game like DF anyways. Simply treat existing dwarves as a wall, or allow multiple dwarves to be on the same tile momentarily (with a very strong preference to stand on their own tile).

Task assignment is DF/rimworld/etc is also pretty dumb — they’re fairly obviously simple greedy algorithms. you don’t need to be anything close to optimal to be effective. There exists a list of open tasks (place building, move x59 stone, fight baddie. User actions generally corresponds to multiple tasks). When a dwarf is idle, he takes the task-list, merges it with his needs (food, water, self-preservation, etc). Filter this list by permitted activities for the dwarf, prioritize the list (needs first, then by user-defined job priority, then by random roll). Lock any relevant object (eg x59 rocks in a move task) and execute.

As far as I know, there’s no attempt at global coordination in DF beyond simple locks — which I’m not sure are actually that strict. In DF I’m pretty sure two dwarves can go for the same pile of x50 rocks, and it’s simply first one wins. In rimworld it’s quite clear only one entity can hold a claim. DF in that case is much simpler and error-free (don’t need to care about dwarves dying while holding a lock) but rimworld’s would be more consistent and make better progress over time (eg a far away entity doesn’t keep getting screwed trying to grab resources from the base).

Pathfinding is largely a solved problem. Resource allocation doesn’t need to be smart.

I’m fairly positive DF’s biggest hurdles are largely in finding game-sufficient and efficient estimate models for complex processes: planet, fluid, wind (a kind of fluid), plant growth, etc. These models are all fairly well defined (to our gaming needs) by their respective communities, but they’re also far more involved than what we need — we just need to be roughly correct, and ideally have a self-stabilizing sim.

The difficulty of gamedev generally is simplifying the problem to find only what actually matters.

[0] http://www.roguebasin.com/index.php/The_Incredible_Power_of_...

[1] http://www.gameaipro.com/GameAIPro2/GameAIPro2_Chapter30_Mod...

3pt14159• 5 years ago

Regarding your edit, I do not disagree. DF does not require a PhD. It would help, but it is not necessary and the people downvoting you, in my opinion, are misusing the privilege.

That said, talking about downvotes on HN is pretty boring, so I won't be replying to responses to this comment.

Supermancho• 5 years ago

One attribute that people don't often ascribe is luck. This was a labor of love and luck.

We hear about projects all the time that have been developed for longer (Linux, Star Citizen, Temple OS, et al) and those are the successes and failures that people have actually heard about. Lots of other people fail along the way (or succeed in not achieving much) with decades of development. I think DF's development need not be elevated to a quasi-religious tale because someone got good enough life RNG, anymore than being born with the money to brute force it is laudable.

h0l0cube3• 5 years ago

As per the article, you don't need a math PhD to code it either:

TA I think I think the math PhD itself didn't because I'm not in like n dimensional non Euclidean space. It's tricky. But But I think having practiced a lot of math and just solved a lot of problems. And generally being good at math. Like I've taught linear algebra. So that part of games is not hard for me, right? It's like and same thing like I'm calculus comes up sometimes. I've used a partial differential equation once it was for like windspeed firing arrows. I don't remember what it was. It was something like that. But it didn't I didn't really end up needing it. I mean, I used it to inform what I was doing but in the end faster just to use discrete simulation and miss a little bit. It's fine to miss. [Tarn laughs]

moron4hire2• 5 years ago

But you do need a math PhD to code it, because if you were coding it, you'd be Tarn Adams, who has a math PhD. There is no state in which one can be "coding Dwarf Fortress" and "not have a math PhD".

h0l0cube3• 5 years ago

I'd posit that there could exist an alternate universe where someone without a math PhD made exactly Dwarf Fortress

bscphil• 5 years ago

The most reasonable gloss on "You need a math PHD to code Dwarf Fortress" is "Necessarily, if someone codes Dwarf Fortress, they have a math PhD." The modality "necessarily" is widely understood to refer to possible alternative states of affairs, not merely those states of affairs which are actual. In other words, if an alternative state of affairs is possible, in which someone (whether Tarn Adams or someone else) codes Dwarf Fortress without a math PhD, then it is not true that it is necessary to have a math PhD to code Dwarf Fortress.

Most people in this thread believe that since a math PhD did not play a crucial role in Adams's ability to develop Dwarf Fortress, then it is true that such an alternative state of affairs is possible. (The language of "alternative universes" - usually called possible worlds in the literature - is one way of getting at this.)

Phrodo_00• 5 years ago

because I'm not in like n dimensional non Euclidean space

huh. I was sure that DF used taxicab distances

pdpi2• 5 years ago

Taxicab distances are perfectly fine in Euclidean spaces

marktangotango• 5 years ago

Ha I was going to quote this exact passage. The "and miss a little bit. It's fine to miss" was oddly satisfying to read.

posterboy• 5 years ago

didn't need language classes either is it? Not that my commenting is free of errors anyway

itsdrewmiller• 5 years ago

This is an imperfect transcript of (casual) conversation.

Cthulhu_2• 5 years ago

It's a transcript; you don't type like you talk either. I know I uh and ahh a lot more, awkward pauses, etc.

joeman10002• 5 years ago

You need a PhD to run it on a Mac.

ajacksified• 5 years ago

It does not take a PhD to download the Lazy Mac Pack. http://www.bay12forums.com/smf/index.php?topic=158322.0

You can even get it as a Brew cask.

easton• 5 years ago

(brew install dwarf-fortress-lmp)

joeman10002• 5 years ago

I did this months ago, it crashes if I generate too large a world. Even if I generate a small world, it crashes a few minutes into gameplay anyway. :(

inopinatus2• 5 years ago

“Everyone knows that debugging is twice as hard as writing a program in the first place. So if you're as clever as you can be when you write it, how will you ever debug it?”

— Brian Kernighan, The Elements of Programming Style

(fortunately the interview itself is not so trite as the headline)

javajosh• 5 years ago

Here's an example: I was writing some code that needed predicates and assertions and at first I did the functional thing and mapped the list of preds into a list of assertions. It worked and was short and DRY, but it had lots of downside, not the least of which is that it ruined stack traces (this was in JS). It turned out to be better to just do the simple thing and statically define a list of assertions that mirrored the preds. It was far longer and more repetitive, but much easier to read and understand.

6gvONxR4sf7o2• 5 years ago

It’s a real shame languages have such shitty stack traces for functional style code. It’s nothing fundamental about the style, so I’m hoping the situation improves over time.

ummonk• 5 years ago

This sounds like one of the many cases that is just begging for good codegen frameworks.

enriquto3• 5 years ago

“Everyone knows that debugging is twice as hard as writing a program in the first place. So if you're as clever as you can be when you write it, how will you ever debug it?”

By becoming more clever! That's the very principle of learning: to become more clever.

The act of debugging your own code to become more clever is a well-known learning technique called "Kernighan's ladder", precisely due to this inspiring quote.

scollet• 5 years ago

That's fun.

I remember writing a little bit of clever (at the time) code for simplicity and speed. Ended up doing debugging and sanity checks via napkin math to confer with my partner because it was easier than reading through the function.

vegai_2• 5 years ago

The act of debugging your own code to become more clever is a well-known learning technique called "Kernighan's ladder", precisely due to this inspiring quote.

According to Google, you seem to be the first person to use that phrase.

Cthulhu_2• 5 years ago

I guess you have a point, but, you don't only code for yourself; the quote applies to others as well, and in practice, few people code in a vacuum.

Don't write clever code; the problem you're solving with code is difficult enough already.

saeranv• 5 years ago

Exactly. I've never interpreted that quote other than encouragement to continue writing "clever" code in order to get better at coding, despite the fact it's typically used to suggest the opposite.

otikik• 5 years ago

I am not an English native speaker, but I think when you learn you become wiser, not "more clever*.

There are things that can increase your "cleverness" like deliberate practice (of mental calculations, of memorization), meditation or deleting social media to increase your attention, or using drugs. I would not call that "learning".

Learning is similar to "installing new software on existing hardware". Becoming more clever is similar to "installing new hardware".

imtringued• 5 years ago

I guess I misunderstood it and falsely applied it to make my code clearer and more effective. I failed to become "more clever" in the process and now I'm doomed to write unclever code other people understand better.

InternetPerson• 5 years ago

Is it already time to gush about Dwarf Fortress again? Wow, time sure flies!

(I wonder if anyone will have a good story where something ~zany~ happened in their game... Fingers crossed!!)

nomel• 5 years ago

These days, my dwarf fortress entertainment comes from the great Kruggsmash on YouTube! He makes very nice artwork to go along with all of the happenings of the play throughs. His presentation is great.

est• 5 years ago

When will DF be playable on Steam?

me_me_me• 5 years ago

Confirmed source from Valve said 'soon'

short_sells_poo• 5 years ago

Also, every time someone asks, it gets postponed by a year. Good job on the parent commenter for pushing it out again...

You don't need a math PhD to play Dwarf Fortress, just to code it

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