Movement

Oculus's movement fails. I can't download any of the movement challenges(All of the links are broken or the site is closed). I don't know how to be sure that it is improved. Are there key bots to test against?

I found a proof that my movement is a failure. Here is a battle result against Raiko.

dsekercioglu.OculusRaikoGun* 2437 (52%) 950 190 1151 147 0 0 19 16 0

jam.mini.Raiko 0.43 2214 (48%) 800 160 1111 143 0 0 16 19 0

You can try to download them from archive.org even when they are broken ;) Hope the links are archived.

Find the bot you think you're notably failing, enable some graphic debugging and watch some matches at different speeds. Go back to your code, wonder what the hell is going on. Repeat. That's how I fixed most of the bugs for my last release. Maybe It will work for you :P

I don't think that it is because of a bug. Every movement I make is really bad. My old bots were built on BasicGFSurfer so no bugs I think.

Hmmm, it's neural, right? Is there any case of success of neural surfing besides Darkcanuck's bots?

As I know Only Pris uses Neural Surfing. Even if this movement is one of the worst in top 100 it is my best movement=). I think that I should tune it more against mid-level guns so it would be better against general.

Looking at your results, I was quite curious about bullet shielders. It's the first time I actually understand this strategy, just watched a game. You get almost zero score against DrussGT, for example. It just sit there and block your bullets. I think I may safely assume those were all head-on shots. One thing I noticed is that DrussGT can't block Roborio, even though it was supposed to shoot head-on for the first shots, while there is no data. Does that mean that I'm not shooting head-on at all, right? That's weird...

One thing that is very important is that a BulletShielder needs to know the EXACT firing angles of your targeting. Even if there is a little deviation, it just don't work. That's why SimpleBot and Roborio should has no problem with shielders.

Yeah, what intrigues me is where this deviation actually come from, since there is a lot going under the hood, and why Oculus doesn't have such "problem". I know it makes perfect sense. It's just too obscure.

First, a BulletShielder would simulate a traditional HOT that is aimed from one tick before, not real fire position, as that position is your position when aiming (onScannedRobot). If it still hits, it would fallback to simulate a state-of-the-art HOT that is fired from real position, which means an advanced firer that predicts its own movement one tick forward on aiming.

However, if you are firing at real position, it is impossible for a BulletShielder to shield without moving. Therefore, for those who fire at real position, a shielder must move a little to be able to shield. And that's where the deviation comes from.

Therefore for a learning gun which fires from real position and is able to learn that tiny move, BulletShielders don't work.

Hmmm, it should be obvious, right? Traditional HOT isn't actually going straight to the enemy's center, so the bullet's intersection has positive length. Anyway, I also thought that the condition for bullets intersecting considered somehow imprecise calculations and that this would be enough to catch traditional HOT bullets, like the use of some epsilon when checking for the intersection. But it seems it's more like the intersection of the segments having positive length or something.

Thanks for clearing it up!

No, the bullet intersection code of robocode is exact, and the deviation of traditional HOT must be calculated exactly as well.

What do you mean by "positive length"? I thought every length should be positive ;p

And I also thought an intersection of two segment (bullets are segments when calculating intersection) is a point ;p It has no length at all.

Sorry for the confusion caused. I just named things the wrong way. When I say segment intersection, I mean the safe area generated by the intersection of those segments, like in bullet shadowing. What I wonder is if, in a perfect universe where computers can compute with perfect precision, two bullets laying on opposite rays would collide or not. Note that the lines actually intersect, so the segments. The safe area, though, degenerates to a single point. So my doubt was like: Robocode actually checks for an intersection of those segments or for a non-degenerate safe area?

Note this degenerated from an actually valuable discussion into a stupid curiosity. :P

Robocode doesn't care about that safe area at all. In segment intersection algorithm, The first thing is to determine whether they are on the same line. If so, robocode just ignores the intersection. This behavior look strange at first, but it is friendly to those who new to robocode. This way they (when trying two stationary robot, etc. sample.Fire) won't confuse — why my robot collides its bullet with another all the time?