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Wi Flag (2002)

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Re: Wi Flag (2002)

#21

Post by btown »

TheRealPomax wrote: post #2

tl;dr: players get attacked based on monster targeting RNG that's supposed to take an interval [0,num_players], assign players to subintervals that are shorter or longer based on a bunch of factors, and then roll a random number somewhere in that full interval. Whoever's subinterval the number ends in, they get targetted. Instead, the code assigned subintervals and then rolled a number between 0 and 1, instead of 0 a…

My startup integrates with numerous third-party data sources, and they'll send quotes in all shapes and colors, usually providing both a total and a complicated breakdown which we need to parse and reshape/classify into line items in our system. And since it's very easy to introduce a bug that skips over a fee accidentally, part of our code review checklist is to ensure that we always explicitly check that our code summing over our final line items sums to the actual ground-truth total; we have a runtime assertion that logs an error to Sentry and, depending on business requirements, shows a (friendly) error rather than incorrect pricing. It's saved us many a time from silly bugs where we're non-exhaustively handling parts of the breakdown data structure.

To generalize, it's vital to have something like Sentry from day one - a low-cost abstraction that lets you monitor broken assumptions asynchronously. Though of course, these kinds of tools didn't exist in 2002!

Re: Wi Flag (2002)

#22

Post by EarthLaunch »

jefftk wrote: post #19
EarthLaunch wrote: post #10

Why does weighted randomness seem so difficult for games? Are there any libraries that simplify this? I couldn't find any for JS. So I created my own "algorithms" for things like randomly choosing which type of plants spawn in the world. It weighs them by the local frequency of each land-type. Eg if there's more swamp nearby, it's more likely to spawn cattails. It's awful. Not intuitive. Weights have to be passed in…

In Python: random.choices(population=['A', 'B', 'C', 'D'], weights=[3, 2, 5, 7]) https://docs.python.org/3/library/random.html#random.choices

Thank you very much! That led me to a JS clone[0].

Python has amazing math libraries. I use numjs[1] for everything, which is a port of numpy. I frequently wish I had use of Python's libraries.

0: https://github.com/parmentf/random-weighted-choice

1: https://github.com/nicolaspanel/numjs

Re: Wi Flag (2002)

#23

Post by Aeolun »

Hmm, when they told me they were assigning people to a list I kind of knew what the answer was going to be.

What is curious is that it took them a long time to find. I’d think that -as long as you believe there is a bug- this should be fairly straightforward to spot.

Re: Wi Flag (2002)

#24

Post by hashkb »

SamBam wrote: post #11
TheRealPomax wrote: post #2

tl;dr: players get attacked based on monster targeting RNG that's supposed to take an interval [0,num_players], assign players to subintervals that are shorter or longer based on a bunch of factors, and then roll a random number somewhere in that full interval. Whoever's subinterval the number ends in, they get targetted. Instead, the code assigned subintervals and then rolled a number between 0 and 1, instead of 0 a…

> A unit test could have caught this I've always wondered the best way to write tests for "This event should happen x% of the time." Obviously we could re-run the test 100 times and see if it happened close to x%, but not only is that inefficient, how close is "close"? You'll get a bell curve (or similar), and most of the time you'll be close to x but sometimes you'll be legitimately far away from x and your test wil…

You can mock the RNG. You don’t need to test/prove it’s random, you need to test your code which is not random.

Re: Wi Flag (2002)

#25

Post by freitzkriesler2 »

EarthLaunch wrote: post #10

Why does weighted randomness seem so difficult for games? Are there any libraries that simplify this? I couldn't find any for JS. So I created my own "algorithms" for things like randomly choosing which type of plants spawn in the world. It weighs them by the local frequency of each land-type. Eg if there's more swamp nearby, it's more likely to spawn cattails. It's awful. Not intuitive. Weights have to be passed in…

I've been pondering a way to implement a quantum random number generator into a game. Could this be useful at all?

Re: Wi Flag (2002)

#26

Post by Goronmon »

Strange to see this exact topic come up twice in two days (the other on Reddit).

But as a huge fan of the original AC, it's always fun to see it come up still.

Re: Wi Flag (2002)

#27

Post by delecti »

SamBam wrote: post #11
TheRealPomax wrote: post #2

tl;dr: players get attacked based on monster targeting RNG that's supposed to take an interval [0,num_players], assign players to subintervals that are shorter or longer based on a bunch of factors, and then roll a random number somewhere in that full interval. Whoever's subinterval the number ends in, they get targetted. Instead, the code assigned subintervals and then rolled a number between 0 and 1, instead of 0 a…

> A unit test could have caught this I've always wondered the best way to write tests for "This event should happen x% of the time." Obviously we could re-run the test 100 times and see if it happened close to x%, but not only is that inefficient, how close is "close"? You'll get a bell curve (or similar), and most of the time you'll be close to x but sometimes you'll be legitimately far away from x and your test wil…

You would probably not test "happens x% of the time", but rather that for a given set of inputs, passing in 0.1, 0.2, 0.3, etc, let you have the expected outcomes across the distribution. So you're testing that you can achieve each outcome across the spectrum with a pre-selected "random" number.

Re: Wi Flag (2002)

#28

Post by [deleted] »

dylanpyle wrote: post #3

I've seen a similar mistake in a rushed "feature flagging"/phased rollout system. User IDs were random UUIDs. Let's say we want to release a feature to ~33% of users; we take the first 2 characters of the UUID, giving us 256 possible buckets, then say that everyone in the first 1/3 of that range gets the feature. So, 00XXX...-55XXX... IDs get it, and 56-FF do not. This works fine. However, if we then release another…

[deleted]

Re: Wi Flag (2002)

#29

Post by dabeeeenster »

xmonkee wrote: post #4
dylanpyle wrote: post #3

I've seen a similar mistake in a rushed "feature flagging"/phased rollout system. User IDs were random UUIDs. Let's say we want to release a feature to ~33% of users; we take the first 2 characters of the UUID, giving us 256 possible buckets, then say that everyone in the first 1/3 of that range gets the feature. So, 00XXX...-55XXX... IDs get it, and 56-FF do not. This works fine. However, if we then release another…

Huh, thanks for this. Will live in my head from now. Basically, in this situation, use (user_id, feature_name) for hashing, not just the user_id.

Haha funnily enough that is our (Flagmsith's) exact algorithm!

Re: Wi Flag (2002)

#30

Post by rcme »

EarthLaunch wrote: post #10

Why does weighted randomness seem so difficult for games? Are there any libraries that simplify this? I couldn't find any for JS. So I created my own "algorithms" for things like randomly choosing which type of plants spawn in the world. It weighs them by the local frequency of each land-type. Eg if there's more swamp nearby, it's more likely to spawn cattails. It's awful. Not intuitive. Weights have to be passed in…

In your example, the weights need to add up to 100 to work correctly, right? The issue with the code in the article is that the weights did not add up to 1.
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