Melee Gun Thrashing

Fragment of a discussion from Talk:Neuromancer
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Yes thats how it works if you take gunTurnRemain() before fire() (worst case is checking against 0) but with 40/distance you have a good value that it happens very rare. You just have to decide whats better for you - shooting one tick earlier (with 40/distance) or shooting more precise with one tick later (zero check). I spend quite a while on this issues and finally decided to go all the way with zero check. You also have to decide what bullet power to use - the one that is used to calculate the angle or the current one. Both have some pros/cons to. Shooting if the last target is not the same as the current target is also something you have to decide.

Hmm its hard to explain for me right now but even with zero check you can end up with not firing. If your gun targeting constantly decides to change the target/area your gun will never (at least less often) be zero as you wish. That mostly happens on loose radars, every time the radar sweeps to the opposite side and finds a better target the gun begins to rotate to this point - the radar sweeps back and decides oh this target is better (consider the movement as well) so the gun has not finished its turn and gets a new target - and so on.

A quite good test to see if your gun has trashing issues related to your movement is putting your bot against 9 Sitting ducks. If he misses some shoots or break the fire frequency to often you have something to change.

If it comes to score, my experience tells me that +-0.3 after 5000 battles translate to no change at all. I see you have a 0.04 difference and this is clearly equal to the last version. In melee it depends on what start battles you get to bring all the pairings up. I have seen jumps of 0.8 score even after 15k battles just because the start battles where to easy.

Maybe it helps: i have a test bed of some sample bots (always the same) and let it run 100 rounds ... i call it 40k/100k+ challenge. 40k = 100 firsts 100k+ = dmg. If your bot loose just one round he has some radar/movement issues. If he gets less than 100k dmg the gun need some changes. To be one of the top bots i guess you have to try 110k+ or more. I use this challenge almost exclusively to decide if i had made progress or not, because it runs fast and has almost every battle state i have to take care of in it. I might be wrong with it but it served me well so far.

Take Care

edit: not sample melee bots just sample bots

Wompi15:41, 3 September 2012

Thank you for the info - I often wonder how other people test their bots =) I know I did a similar technique for 1v1, I test a lot with DoctorBob to get my surfing right, as well as RaikoMicro for my stats systems. It seems to have worked well there =)

However, you have the ways I check for targeting error wrong. The first way (1.9) aims, then checks if the gun is within 40/distance. If so, we fire. The other way (2.0) checks if gunTurnRemaining() is 0, sets gun to fire, THEN aims. So, the second way will fire more than the first way even though it is checking for 0 instead.

Skilgannon17:00, 3 September 2012
 

Uhh mate stop confusing me :) .. i thought i figured it out and would never think about it ever again :)

The way you describe it was how i was understanding it.

1.9: gun heat has to be zero
calculate angle
check angle (if you check here against zero it almost never shoots, but with 40/distance it will shoot)
fire
next turn: bullet is on its way

2.0: gun heat has to be zero
check angle (zero)
fire
calculate angle
next turn: bullet is on its way

So both versions are the same, they shoot one tick after the gun heat is zero. But 1.9 has the advantage of shooting in cases where the gun is almost pointed to the target where 2.0 has to wait one more turn. If both versions are already pointed to the target then there is no difference. Thats how i understand it and therefor it looks to me that the first one shoots more often and the second one is more precise. Am i wrong with this? Man this stuff really confuses me :)

Wompi19:00, 3 September 2012
 

Hopefully I won't confuse this further, but I think the two options are:

  • Style 1:
    • if (gunTurnRemaining() == 0) then fire()
    • re-aim (won't effect angle used in fire())
  • Style 2:
    • re-aim
    • if (gunTurnRemaining() < 40 / distance) then fire()

So the first option just sees if your aim from last tick has completed, fires, and then continues re-aiming for next tick (which won't affect this tick's firing angle). The second option requires that the firing angle remains somewhat stable from last tick to this tick. It's also sort of the case that the first option is aiming 1 tick further into the future, since the second option will hold off firing if the aimed firing angle doesn't line up with the next tick's firing angle. FWIW I used to do Style 2 (Dookious, early Diamond, but with 18 / distance) and now use Style 1 in Diamond.

Voidious19:47, 3 September 2012

Style 1 makes it a lot easier to deal with firing pitfall.

MN19:53, 3 September 2012
 

Sorry, I guess maybe that was clear already. The reason the zero check thrashes less is that it only requires that the last gun turn was <= 20 degrees, while "re-aim and check within threshold" requires that the firing angle somewhat lines up two ticks in a row. (Though 40 / distance is a pretty big threshold, too - I always used 18 / distance.) And while the zero check is more precise, it's also in a sense projecting one tick further in to the future, since the other one is effectively aiming one tick later (by vetoing if the current gun heading isn't close to how we'd aim this tick).

Voidious19:56, 3 September 2012