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GF assumes symmetric movement, which is safe. Also assumes orbital movement, which is not as safe, but still hard to exploit.

GF combined with statistical targeting, also assumes non-adaptable movement, which is not safe at all. Exploited by all surfers.

MN (talk)20:31, 18 December 2013

How does it assume orbital movement? If you're not staying perpendicular to me, my GF gun is going to crush you even harder.

Voidious (talk)20:36, 18 December 2013

In practice, yeah, because the whole point of perpendicularity is to maximize your MEA. But, GF guns are actually assuming that the enemy is orbiting when it visits those GFs. For example, SittingDuck and RamFire both stay at GF0, even though they have very different movements. I'm definitely not saying that this assumption would be easy to exploit, especially with segmentation, but it could be, in theory.

Sheldor (talk)21:22, 18 December 2013

I still disagree that GuessFactors introduce that assumption. A GF is a scalar value representing the whole range of firing angles the enemy could reach. Orbital movement maximizes this range and distributes the values most evenly across it.

How about this: What if I used raw bearing offsets instead of GuessFactors? Do they assume orbital movement?

Voidious (talk)21:30, 18 December 2013

The way I think of it is... besides the clockwise/counterclockwise thing, the other assumption that GuessFactors make is that the movement profile either stretches with BFT (or more directly MEA) or that BFT is rather constant.

Raw bearing offsets are similar except that they don't apply such a stretching, and instead assume that either BFT is rather constant, or... bots are breaking the physics rules... no that doesn't count... they just rigidly assume BFT is rather constant.

The main innovation of GuessFactors over raw bearing offsets is that it generalized what was assumed as to be less rigid, but it still makes some assumptions. Further, things such as segmentation by BFT or MEA tend to mitigate the effect of this specific assumption.

Rednaxela (talk)21:58, 18 December 2013

Basically, I don't think GuessFactors assume anything (besides symmetry) that isn't already true based on the physics of Robocode. Your input to firing a shot at your already chosen bullet power is an absolute angle (modulo your current gun heading). A wave collects what should have been the input to that API call. To me that seems about as close to "making no assumptions" as you can get.

So I'm forced to ask myself: why don't you use GFs in Melee? Doesn't that prove they assume an orbital movement? But I really think it's more that you can assume non-orbital movement in Melee, so it's advantageous to do so (PIF, displacement vectors).

Voidious (talk)01:55, 19 December 2013

I'll give you that it assumes a movement profile that scales with bullet flight time. But that's a very light assumption and not the same as assuming orbital. What types of movement don't scale with BFT? Just fixed patterns?

PS: Mathematically, I think bearing offsets would assume bullet power is constant, not BFT, right? ;)

Voidious (talk)02:04, 19 December 2013

No, because bearing offsets have no relationship to MEA. I think that raw MEA is the source of the orbit assumption in most guns. The raw MEA is assuming that the enemy can reach all those possible future locations by the time the wave hits, which it can't if it isn't orbiting. Precise MEA pretty much solves this.

Sheldor (talk)01:32, 19 December 2013

Why is that an assumption they will ever go there? It's only taking into account that they could. If they never go there, what's the difference? If your bot has a min GF of -0.1 and a max of 0.3, it wouldn't make my gun any more accurate to change my MEA to match.

Voidious (talk)01:41, 19 December 2013
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