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Old discussions from 2006, from 2007.

Virtual Bullets

Are you sure we should have Virtual Bullets redirect here? It is not mandatory for a virtual guns system to use virtual bullets - for example, in an upcoming version of Horizon, I plan on implementing a virtual guns system that treats the success rate of a gun as the rolling average of 1 - (abs(predictedGuessFactor - actualGuessFactor) / 2). Obviously, this system will use waves, not virtual bullets. Furthermore, some early GF-like guns used virtual bullets instead of waves for enemy position logging. There are obvious bot design applications where one system does not overlap with the other. --AaronR 20:57, 29 November 2007 (UTC)

Yeah, I was wondering if they should each have their own pages. I'm definitely open to that. But after some consideration when making the page, I was thinking that they are not really describing different things. I definitely think it's worth discussing...
I also implement my virtual guns with waves instead of tracking the frame by frame location of each bullet, but: a) they are still "virtual bullets", in my mind; b) even if virtual guns doesn't need virtual bullets, that doesn't mean virtual bullets can exist without virtual guns. Wouldn't a virtual bullet always come from a virtual gun? Would you not consider those early GF systems to be an array of virtual guns, each aiming at a fixed GuessFactor?
Still, the history of each idea is unique - like you said, the term "virtual bullets" was used in those early GF guns, while "virtual guns" tends to imply a specific algorithm for each gun. But I think it will be tough to really differentiate the concepts. --Voidious 21:16, 29 November 2007 (UTC)
Oh, another factor in my initial decision is that the respective pages on the old wiki seem pretty clearly to define them as the same thing. The top of the VirtualBullets page includes David Alves first showing a picture of different targeting systems firing virtual bullets in a virtual guns array (including linear and head-on), and then a comment describing the old virtual bullet GF system. Actually, I'd really like to hear his thoughts on this. --Voidious 21:44, 29 November 2007 (UTC)

As a kind of side bar to the above discussion: if we do leave these as one page, we should definitely add the original style of GF guns to this page somewhere - perhaps under "common uses" section. --Voidious 19:37, 30 November 2007 (UTC)

Question! What is a "decay rate"? What else do you need, if you keep track of the number of hits for each gun? I think the results would accurately express which gun is better.. -- Josh S 12:38, 27 April 2010 (UTC)

"Decay rate" means a way of making newer data more relevant than older data. For instance, for a hit percentage, if you just used the last 10 shots instead of all of them. Or if you were storing shots fired vs shots hit, dividing both by 10 every 100 shots. --Voidious 13:53, 27 April 2010 (UTC)

Hmm.. OK, I think I understand... So it's sort of reducing the data size, as it gets larger? -- Josh S 01:41, 28 April 2010 (UTC)

Well, it's more about making new/current data count for more. By dividing shots hit and shots fired by 10, you are basically decreasing its weight of that data from normal to 0.1. One of the most common forms of data decay is Rolling Averages, you should definitely take a look at that. --Voidious 01:53, 28 April 2010 (UTC)

Well, you can choose between 'decaying' the date (better for adaptive movement) or just plain accumulated data (better against random mover and non-adaptive movement). It just like GuessFactor gun with and without Rolling Average. --Nat Pavasant 14:36, 27 April 2010 (UTC)

What do you mean by the "date"? By plain accumulated data I suppose you mean hit rates, and the number of shots fired... -- Josh S 01:41, 28 April 2010 (UTC)

Sorry, it should be 'data'... --Nat Pavasant 06:48, 28 April 2010 (UTC)


Thread titleRepliesLast modified
Multiple bullets per gun713:32, 4 October 2011

Multiple bullets per gun

I take it as a given that we all choose the wrong gun pretty frequently. I use precise intersection and normalize hits by distance and MEA. So a hit percentage of 12% from distance 400 is rated the same as 6% from distance 800, for instance. I think this is all pretty optimal, but we still just don't have much data. There's the option of firing a virtual bullet every tick, but this seems inaccurate.

I got the idea to not just fire a virtual bullet for the best angle produced by each gun, but also for 2nd best, 3rd best, etc, with progressively lower weights into the VG stats. I felt this had a lot of promise and I spent a few days tweaking various configurations, disappointed to find no improvement in my test bed. But I liked the idea enough that I figured I'd give it one shot in the rumble before moving on. I'm not convinced this isn't random fluctuation or a side-effect of the Anti-Surfer gun changes, but 0.1 APS improvement: [1]. Anyway, just thought I'd share. Maybe I'll revert the VG changes in .14 for a direct comparison.

Voidious16:10, 3 October 2011

In my humble opinion the best virtual gun array is no virtual gun array. It add's a great deal of complexity for marginal benefit in most cases. Just try to make the best gun better.

Chase-san17:17, 3 October 2011

In order to hit both DrussGT and RandomMovementBot12345, you're going to make a trade-off somewhere, whether it's by adding a VG or by sacrificing performance against one to hit the other when tuning a single algorithm. I don't consider it that complex. Improving my Anti-Surfer gun is what got me beating Shadow, which is reason enough for me to have one, and more than a "marginal benefit" in my eyes.

Voidious17:43, 3 October 2011

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Anyway, on the topic of "multiple virtual bullets", I have tried something like this before, except I took it to the extreme. What I did in some versions of RougeDC is equivalent to what you suggest except with infinite differently weighted bullets. It integrated the result across the angles.

My experience is that this method was much faster adapting than the conventional single bullet approach. It was very useful against surfers that you need to adapt quickly against (i.e. swapping targeting systems when they've learned one too well). The disadvantage, is that it converges to a less accurate result.

Rednaxela21:51, 3 October 2011

That's interesting to hear. I definitely considered some extreme cases - for instance, for the hit angle, take the normalized score for that angle (eg, kernel density / max kernel density) as the amount of a virtual bullet hit to count it as. Is that something like what you did? Obviously that's biased towards a gun with a pretty flat graph, but even after normalizing I'm not sure if it would favor one of my guns, which have very different looking graphs.

I have a hunch that this type of system should break down (ie, become so noisy that it's counter-productive) very quickly beyond the first few angles - if it helps at all in the first place. But, not being sure on the theoretical level, I definitely felt that on the experimental level, if I couldn't find benefit in using only 2nd/3rd best angles (which also by far carry the most weight), I would not find it by going beyond that.

In any case, I found no improvement in anything I tried, including the variation I'm trying right now that I thought fixed a flaw in 1.6.13's setup. So I'll probably try 1.6.14 with the old VG and see how that goes. I do still think there's potential here.

Voidious23:36, 3 October 2011

I've had a problem with the way we normalise our data - I think it should be normalised so that the area underneath the graph is 1, not the maximum value is 1. This would make this technique more useful, as you could simply integrate each gun over the hit area and use that as its hit ratio. I've also had the idea of dividing all my VG hit ratios by the random hit ratio - so that the gun hit-ratios are measured in a useful metric that adapts across bots. But back to designing my genetic gun-weight tuning algorithm!

Skilgannon07:02, 4 October 2011

Yep, I do normalize against the random hit ratio, in effect, by scaling with distance and precise MEA whenever I log a hit. Regardless, 1.6.14 looks well within the margin of error of 1.6.13, which is in line with all my tests of the multi-bullet VG, so I'm happy to revert a bunch of worthless code. =)

Voidious13:32, 4 October 2011
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