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A little info on the new RNG system.

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    A little info on the new RNG system.

    With version 1.147.1 we changed how random works. Until now we used PGC random( without any extra tinkering so it was as close to a true random system as possible. In practice this can lead to unwanted game play experiences which statistically are likely to happen but are very annoying to deal with ( bad streaks ).

    In the new system which still uses PGC random we added an extra modifier which in practice acts like a luck factor, for example if your probability of hitting a roll is high( let's say you have 80% crit) and you miss, your luck factor increases , so the next roll you will have a bit of bias towards hitting, the same happens when you hit on a high prob of missing.

    In practice this will remove streaks with low probability(very bad streaks) and also it will distribute hits/misses more uniformly without removing the unpredictability of a true random system(to a high degree).

    To better understand here are some tests using both systems. Each simulation is done with a target chance and 100 rolls where '-' is a miss and 'X' is a hit, we use 100 because it's close to what happens in Ironbound where for example you use an item(weapon) 20-30 times per game so the sample is pretty low.

    Here are two tests with the old system:
    ----X-XX----X-------X-----XX------------X-----------------X-X-X--X---X-XX-XX--X--X-X-XX---X-----X--- (target chance 30%, actual result 24%)
    ---XXXXX--XX-XX--------X--X----XXXX-X-----X---X-X-X-X-----X----X-X--X-------XX-X----XX---X-X--XX--X- (target chance 30%, actual result 35%)
    As you can see we can have big streaks , 5 hits which has a 0.24% chance of happening, or a 15 miss streak with has a 0.47% chance of happening. Also because the test was run for a relatively low number of examples(100) the error is pretty big.

    Here are two tests with the new system:
    -X---X---X-X-X--X---X---X---X--X-X----X--X--X----X-X---X--X-X---X---XX---X----X-X---X--X----X---X-X-(target chance 30%, actual result 30%)
    --X--X--X--X--X--X---X--X---X--X---X-X--X--X----X--XX-----X---X--X--XX----X--X--X-----X--XX-----XXX-(target chance 30% actual result 31%)
    Here we can see that the hits are move evenly distributed, we still have streaks(2,3 hits in a row) but don't have any big, low probability streaks.

    Also this new function works pretty well with varying target chances(for example buffs).

    More tests here:
    old rand :
    new rand :

    I'm curious how people feel about RNG now that you've had this system for two months. Any thoughts?


      Predictable. I've got builds that are viable based on how predictable it is.


        Perhaps it is better as it is now for the critical hits series, but too much predictable for items such as berserker's reinforce: you can trust to have 1 certain extra hit in the row of three but, as well, you can be sure no more than 1 extra .
        Parry: after 1 parry, you can trust you will not have another parry, if chance is about 30%.
        I am not sure this makes better the game.
        let's try for a season.


          Originally posted by David (Producer) View Post
          I'm curious how people feel about RNG now that you've had this system for two months. Any thoughts?
          I think the modification should be dialed back a little. The sweet spot is probably somewhere between the modded PCG generator (current implementation) and the unmodded PCG generator (old implementation). The high level of predictability of the new implementation creates a somewhat stale gaming experience. At the same time, the crazy low probability streaks of the old implementation were somewhat soul crushing, so to speak. Although, if a happy medium can not be reached, or if there is no such thing as a sweet spot, then I would say that a stale game experience is far less desirable than a soul crushing one. I like my tea hot or iced, but never lukewarm.
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