Talk:Main Page

For old discussion, see Archived talk:Main Page 20110903.

I'm trying to modify the robocode game for a University assignment and I'm currently stuck so if anyone could help me that would be greatly appreciated. To modify the game I decided to create a new robot type that freezes other robots for a certain amount of turns when it runs into them. I have created a new interface for the freeze robot and altered some of the other code. When the game starts up it goes through all the robots that the user can choose from and creates a RobotPeer for them. And for each RobotPeer they all have a RobotType. If I debug the game here I can check the FreezeRobot that I made that implements the interface and it shows that it has both type FreezeRobot and AdvancedRobot. Which is what I want because if it doesn't implement AdvancedRobot then it can't use any of AdvancedRobot methods. So up till here everything is fine.

Though when I select the FreezeRobot and start a game with it then debug to check the RobotPeer, it is now only an AdvancedRobot. Can someone explain why this is?

In case you are wondering, what I am trying to do is to make edit the RobotPeer code in the checkForRobotCollision method. After it creates a new HitRobotEvent and sends that to the robot, I want to check if the otherRobot is a FreezeRobot and in this case it will change some variable that makes the robot frozen. I haven't worked that part out yet but I need to be able to see if the otherRobot is a FreezeRobot first so hence this post.

If anyone has any advice/tips/help it would be greatly appreciated. Thanks

Hi mate. Not sure if someone here can help you with this. Maybe you should ask your question (or just link it to this post) at the help section of SourceForge Forums. I guess Flamming can say something that might help you.

I hope you keep us informed how it is working out :)

Take Care

Yeah, on the wiki we more deal with robot development than with actual Robocode development. You might want to check out the robocode-developers Google group as well.

Good luck!

Perhaps it is only declared as AdvancedRobot in RobotPeer, but the instance is a FreezeRobot (and, more specifically, your robot class)? If you were seeing the instantiated type, it would show as your robot class. No matter the declared type, in Java you can do "instanceof" to check whether the actual instantiated object is a certain class (like FreezeRobot, or DrussGT), so maybe give that a shot and see if it works.

But yeah, as these guys said, the robocode-developers group and project forums are better places to get input from people who actually work on Robocode. They don't compulsively check the wiki as often as us Robocode addicted bot authors. ;)

Ok thanks I'll try the developers group.

Also I tried 'instanceof' to check the type but it makes a compile error because RobotPeer cannot be compared to FreezeRobot.

Sorry - I meant where ever you're debugging and seeing an AdvancedRobot when you want to see a FreezeRobot, try instanceof on that variable. It's probably true for "instanceof FreezeRobot", which is one way you could test the type of a robot - though probably not the fastest way, so you might want to figure something else in final implementation.

Hey guys, I'd like some input on this. Sometimes it bugs me that the wiki is so disorganized, so much content out of date or needing refactoring, so much unmigrated content on the old wiki. Other times, it feels very organic and like it servers its function perfectly. I'm not sure if spending tons of time cleaning up and migrating old content is really worth the time, but if it is, I'd gladly pitch in on that.

What do you guys think? What would make the wiki better / more usable / more useful / more fun to browse for you?

Personally, I find myself browsing talk pages a lot - it would be nice to have some saner way to browser old / interesting conversations across the wiki. I'd also like to get lots of old bot pages migrated - maybe a semi-automated way of doing that would help.

I´m quite confortable with the wiki the way it is. The only thing that bothers me a bit is having to search for a keyword twice, once in this wiki and again in the old one. Although Google can be a workaround.

I agree that there are some places that need cleanup and such. For my own part, I just need to be bold and go ahead and touch up things when I see them, and not be so afraid to add things. I personally feel far too outclassed and overshadowed by the giants of Robocode to feel myself knowledgeable enough to speak on lots of things, despite my rather thorough mathematical training at university. That might be fixed somewhat when I can get my bot a bit closer to the top of the rumble. *chuckles*

One things that's interesting to think about is the "ownership" of bot pages. There are a lot of bot pages that feature time-specific information (mostly about the bot's current rating) that's quite old indeed. These are bot pages whose authors seem to have left the community, at least for now. The status of what's considered polite to do there is a conversation worth having, I think.

As far as things the wiki could add.. I've noticed lately that there's a Robocoding-term/bot-component that gets mentioned a lot in talk pages and bot version histories and so on, but that doesn't have a wiki page explaining it whatsoever. I've been fiddling with adding this aspect to my bot, and recently decided to scrap everything I've done with it and start it over as a proper Object so it doesn't make a mess of my already messy movement Object. Can anyone guess what it is?

Flattener?

Reminds me... When I started in late 2005, the whole top 10 was Wave Surfing, but there was basically no centralized info on what all is involved or any of the gory details. Sometimes it takes a fresh pair of eyes to notice these gaping holes in the wiki's coverage of topics. =)

Bingo, flattener.

For migrating things over from the oldwiki, a talk page to help coordinate that project might be useful.. maybe have folks vote on whether or not certain articles should get moved over?

I'll try to be more proactive in helping to tidy up and extend the wiki. The information and conversation here is a big part of why I love Robocode! :)

There, started a little stub for Flattener. That's a start anyway :)

Is there a way merge two pages? Or better what is the best way to merge two pages with all the history and discussion stuff? :)

Hmm... I don't think there is a way to merge pages that preserves history for both. I suspect the best option would be... move the page with the most history/content to the new name (if it's not already the correct name), and add the content and discussion-history from the other page.

One thing that could maybe be done is have the "edit summary" include a link to the history of the other page. That way a link to the other appropriate history is there when people are viewing the page history.

I feel like some parts of the wiki could use a little cleanup to expanding on yeah, though I feel that for the most part it works as it should.

Hmm.. MN's comment about search makes me think that if I find some time, I may look into making a little mediawiki plugin to make the search results also show things for the old wiki.

Yeah, I use Google with site:robowiki.net quite a lot myself. That would be pretty cool if you could do that. If not, maybe a custom Google search box could work.

I would like to see something on the main page that shows that the community is active. Maybe some parts of the recent changes, current discussions, lately visited pages or last updated robots. Because when i started with robocode and came to the robowiki (trough the robocode page) it looked to me very abandoned because i was not familiar with the "recent pages" or "talk pages". I had a lot of questions and had no place where i could ask. I think i hit the first talk page by accident 3 month later and it took me even longer to find the "recent pages" (i know its a shame because it is linked on the main page). But i guess if you are not used to how wiki works behind you didn't notice it is there.

Some informations are hidden quite well if you don't know what you are looking for. Lets say the code size related pages. The informations about code size are spread over 3-5 pages i guess and you really have to know what you are searching for.

After i got used to the wiki i found out that most of the interesting informations are on the talk pages. Maybe it is possible to integrate the discussion threads, if they relate to the content, as links in the wiki page as well (probably -1 for bad style but it would save the time to edit the page after each new discussion).

For editing/making pages i would second Tkiesel and feel outclassed and overshadowed by the robocode veterans, plus i don't think my spelling is appropriate for that. I'm also very afraid of moving/summarize pages or insert relevant links because i can not estimate the damage it would bring.

Lately i was in the moot to make a bot pages for the probably most influencing bots to the robocode community - the sample bots :). Just because i think they deserve it and probably most of the robocoders have struggled against these little buggers. I don't know but i guess it would be nice if the new robocoder can start from these bot pages to discover the wiki basics. For example links to linear targeting on Walls or circular targeting an SpinBot, radar lock on SittingDuck or orbiting movement to show how to circle around SittingDuck and so on. My guess is, it would be some sort of entertaining tutorial, and also leads to the feeling what you need to make a robot. I don't know , maybe i'm wrong on that.

All in all i can say, now that i'm a little more used to the wiki i'm very happy with it and like the way how it bonds the community. I'm keen to help with whatever you need.

Take Care

If you want to make new pages, or edit anything, please just do it. If you want to change the main page to show more prominent links to Recent Changes or some sort of howto for the wiki, go ahead. If we don't like it we'll say. After all, it is easier to get forgiveness than to get permission =) Myself, I hardly ever look at the main page, I just bookmark Recent Changes.

When I first came to robowiki (2005/6 or so, I think), I also didn't see the recent changes page for about a week and was impressed that everybody managed to find my page. Of course, that was on the old wiki, but I think a lot of the same problems are still around.

I agree, what the wiki needs is something to get beginners acquainted with the layout (the talk pages, recent changes) and maybe a glossary of commonly used terms and 1 line explanations of them (VCS, wavesurfing, DC/KNN, flattener, HOT etc) with a link to their page. I'm busy over the next few weeks (off to Mexico for Robocup 2012!!), but feel free to do whatever you feel will make the wiki better. The wiki is a community resource, and as part of the community you are strongly encouraged to do whatever you think will help the most! If you want to update old bot pages, or migrate anything over from the old wiki, just go ahead.

Hi mates. I'm planing to link the wiki pages related to the Robocode terms to the terminology category. I think it would be a good source to browse the robowiki pages. Also can you get a fast look on everything that is interesting i guess. Would that be ok for you?

Is it possible to automate something with wiki commands? I had in mind to make a table on the main page where every new entrant to the paticipant pages is linked. So you can see the latest bots who are updated added and whatnot. Not sure where i should start to bring this to life.

It would be great if some of the native speakers could correct my spelling or rewrite some stuff that sounds weird or not appropriate for the official pages. For me it would be a great opportunity to see where i'm wrong and i would not be offended by that at all.

Anyway Take Care

You can write wiki bots to communicate with MediaWiki via APIs. I do some of this with User:VoidBot, and Nat has also done some. If you start working on any wiki bots, let me know and I can give your bot user the "Bots" permission (if you promise to be careful =)). Darkcanuck's RoboRumble server also has an API you can play with: Darkcanuck/RRServer/Query.

I do some neat auto-tracking of RoboRumble activity (which uses both those APIs), and posts its output to @roborumble on Twitter. I've thought about displaying this somewhere (Main Page or RoboRumble), but I'm not sure how to embed a Twitter feed in the content of a page. It's easy for @robowiki in the sidebar because I can just use regular HTML/CSS/Javascript, but the content of wiki pages is handled differently. I'm sure there's a way, maybe with a custom extension?

Hmm i guess the wiki bots is nothing for me by now. But i could think of using the RoboRumble API or even better would be to embed your twitter feed on the main page to see whats going on in the rumble. A quick goggle search told me there is a widget called "Twitter Search" that can embed Twitter feed in wiki pages. This would need the widget extension for this wiki. Not sure how much trouble it would be to set up these things.

I will have a closer look at the RoboRumble API to and maybe i find something that could make this happen.

Btw. the roborumble twitter is indeed very neat .. well done mate

Hia I've only just started using robocode and I have never coded before doe anyone know any good tutorials out there ? Or could you give me any tips on how to get started. Any advise would be appreciated.

Hi Rigged!

The Tutorials on this wiki are great resources, especially Getting Started, My First Robot and Game Physics.

If you're brand new to programming entirely, I'd suggest that you also immerse yourself in some other avenues to learn programming concepts generally and Java in specific. Greenfoot is a tremendous tool for learning basic programming concepts in a very "object-oriented" way, with some great tutorials available.

There are also several good beginner's tutorials on Java in general.

Hi Rigged, welcome to Robocode. I had about 6 months programming experience at high-school (10th grade) level when I first got involved in Robocode. Although RC is a great way to pick up on programming, I do think it is important to have a tiny bit of knowledge of how the basic concepts etc work before starting. Once you understand what a class is, what a method is, and the basics of mathematics in a Java context (plus a bit of geometry/trig) you should be ready to start. The sample bots are lots of fun to play with, and understanding how they work is a great way to pick up on some of the concepts. Once you get there, just ask us what you should got for next and I'm sure you'll get tons of advice =)

Thanks for the advise :). I've started by building a simple robot and i was wondering how do you change the colour of your robot.

Hi. Lets talk about your questions on your user discussion page :) User_talk:Rigged. I think it would be to much for the main page and you can ask whatever you want there.

take care

Hi

My name is Andrew Kirkland. I am currently writing a dissertation at the university of Abertay in Dundee(Scotland) which involves the use of Genetic algorythms to program robots in Robocode. I came accross Robocode JGAP . I have been testing it out but the webpage does not give me much information. Is their a user manual available for this software. I also need some general information on how it works for example the genome and what each of the 6 numbers represent, the fitness function, etc.

Any help would be much appreciated

Thanks

I don´t think anyone here is using Robocode JGAP. But I know genetic programming algorithms are being used with success in RoboRumble.

Currently, the most successful uses of genetic programming algorithms combine conventional development os robots without it, then using genetic programming algorithms to find optimal constants in statistical methods, like parameters in k-nearest neighbors search, kernel density estimation or histograms.

Hi,

I've read about the differences between a Robot and an 'advanced robot' But there is a basic thing I do not understand : Does an advanced robot has an advantage in the battle field over a similar robot, because it can perform several action in the same tick?

As i understand it, if i call ahead(..) followed by fire(), a regular robot will call ahead (and block until it is done) and then fire, while an advanced robot calling setAhead(..) and setFire() will start moving forward and will fire at the same tick, thus having an advantage over it's fellow regular robot. that sounds weird, though..

Am i wrong?

Thank you very much yoni

No, that's how it works. The only disadvantage I can think of is that Advanced robots can lose energy by hitting the wall. Personally, I find Robots boring and Advanced robots awesome, but maybe there are people who actually liked normal robots. Welcome to the wiki!

Thank you very much for the prompt reply.

So why on earth will someone write a regular robot, if a similar advanced robot will kick his ass? is it just a history thing?

The author of Robocode thought Robot would be an easier starting point for beginners. I'm not really sure it is... And as for fairness, I'm not sure he could foresee how competitive Robocode would eventually become. :-)

As for why still write one? Sometimes people like writing bots under different constraints, even if they're silly. The most popular example would be weight classes based on Code Size (Mini/Micro/NanoBots), which even got their own Rumbles. People have also written Robots, Droids (+20 energy, no radar), and Perceptual Bots (don't store any state, even between ticks). Of course, comparing such bots to DrussGT is unfair =), but that doesn't have to ruin the fun. I recently wrote a Perceptual Bot myself (RetroGirl).

Someone can write a robot just for fun. Why there are races on bicycle, when you could also ride a motorbike. Why we have code-restricted classes. Mind you, the best robot (kawigi.robot.Girl) is not easy to defeat, especially in melee. Most school competitions I know of use Robots, as it probably easier to check and control the code and its behaviour, and to prevent 'lending' code from good bots out here. For me, writing a robot is more difficult than writing an advanced robot, because it is hard to wrap my mind around what to do when and so on.

Hi,

Thanks for he answer. I didn't mean for question to be offensive (as in "why should one bother to write a Robot and not an Advanced one) I just wanted to make sure i understood correctly that the Advanced indeed has more power in the battle field.

Yoni

RoboRumble could have an "extends Robot" category.

Hi mates. Is there an issue with RoboWiki? It is very slow and sometimes it even didn't responds.

Yes, I've also noticed this. I suspect a search engine may have been spidering, or perhaps a database backup was running.

I as looking into this on the server today, and it looks to me like the main thing loading the wiki down is Bing being ridiculously aggressive with it's spidering... :(

I'm not really seeing anything on EverythingRobocode that makes it worth having a prominent link on the front page. I don't want to seem like I have a problem with other sites about Robocode coming into existence, because I think it's great. If at some point it has a ton of original content, by all means we should link to it. But right now, it looks like just a few articles, and this is a pretty elite set of links. Could you just post a link on your user page for now?

I agree, we cannot link every page about robocode on the front page, only the most important/informative of them. Compounded the need to add a description as well, which is a bit needless. I will remove it (the link+desc) for now.

Maybe an External Links page filled links? And then link the Main Page to that page.

Hi everyone, Im new to this group but am hoping you might be able to help me out with a project I am going to be running at my school this term. I am going to be delivering an introduction to programming for some Yr 9 students (13 - 14 year olds) starting out with basic programming ideas and examples and then moving onto a group project where teams of students create their own robots using robocode. They will have regular competition against each other to see what team is making the most progress / come up with the best ideas.

The reason I am telling you all this is that I am looking for some mentors to help out and perhaps give some advice. All this would involve is you perhaps receiving 1 or 2 emails with some code or some questions about how to do something. This kind of interaction is really useful for students as they get to work with real experts and feel like they are being listened to and treated like adults.

The project will run for about 6 weeks and will start mid february, as I said it would only involve a couple of emails or perhaps a Skype session. The classes are all small and the students are really hard working

I would be very grateful if you would consider helping out and if you have any questions please fell free to get in touch with me.

Thanks for your help,

Darren

I'm happy to help. I'll be very busy over the next few months getting my project ready for the international Robocup, but the occasional email should be fine.

I'm ready to help, but i'm afraid, that my english skill can become a problem

Thanks for the quick reply, its great to hear that people are keen to help out! I guess the best way to move forward would be to share some contact details. I will then give these out to the students once we start the robocode part of our project around the middle of february. Perhaps each of you could mentor a couple of teams therefore limiting the number of emails you will be getting.

It would be great if you could perhaps tell some other people about this project and see if they would also like to help our as the more people we have involved the better!

My email address is dsutton@nlcsjeju.kr, please email me from the account you would like students to contact you at so that I can start putting a list together.

Thanks again for your help and I look forward to hearing from you and perhaps some other willing helpers soon.

Darren

I'd also be glad to help. Projects like this are always interesting :)

actually i think that every active robocoder is ready to help. and there are google+ circle for robocode: https://plus.google.com/102023615133629629984/posts?fd=1

Thanks for the great response, I've had quite few replies and am also looking for mentors from other more general programming areas as well. If you think you might like to get involved please contact me and I can tell you all about it.

The students had their first programming lessons this week and are really excited, particularly by the idea of working with robocode and having mentors they will be able to contact and share ideas with.

If you have said you will be involved or would like to be can I ask you to send me a quick Bio about yourself and your experience that I can give to students so they can find out a bit about you. It would also be great if you could supply a picture as well and this could be an avatar if you like, It would be nice if students could put a name to a face!

Thanks again for all your help, if you know of anyone who might be willing and able to help please put them in contact with me.

Darren

Just for the record, the downtime this weekend was my fault. Got the server into a nasty OOM state when trying to optimize performance. It should be working properly now (and still faster).

If anyone is noticing Robowiki being slow, it's because a PHP process is hitting a cpu bottleneck right now.

The logs are showing Bing and Baidu doing some heavy spidering right now so it could be that... but it could be something else, I'm not 100% sure.

Are you using php-fpm or spawn-fcgi? From my test, the former performs better under heavy load (though I am not sure since I tested it with nginx, not lighttpd; tested with apachebench with wordpress installation)

fcgi, however the number of requests per second was fairly modest really, so I doubt that type of overhead was the issue. More likely something on the MediaWiki side was being inefficient on the particular pages being spidered I think.

Yay for speedups! :D

I did some tweaking to the server configuration... according to benchmarks I improved things so that Main_Page went from 5.41 requests/second, all the way up to 80.71 requests/second.

Special:RecentChanges improved less though, going from 2.26 requests/second to 3.44 requests/second.

What's the means of "APS","Survival","ELO Rating","Glicko-2(RD)","Battles","Pairings","PL Score" in the RoboRumble?And how to work out them?

"APS","ELO Rating","Glicko-2(RD)": Darkcanuck/RRServer/Ratings
Premier League: [1]

Survival - it's average percent of rounds where robot survive
Battles - it's count of battles in which robot takes part
Pairings - it's count of another robots with which robot has battles
PL Score - it's count of wins in pairings (score percent > 50) * 2

for example robot A has 2 battles with robot B with score percents (45, 60) and no battles with robot C. In this case APS will be (45 + 60) / 2 = 52.5; battles will be 2; pairings will be 1; PL Score will be 1 * 2 = 2

soga,thank you ^_^

I just switched to a Sandy Bridge computer recently, which I believe has the most aggressive Turbo Boost nowadays (not counting the AMD Bulldozer, which I am not sure). I find that a lot of older robots started to skip turn like crazy (DrussGT is like skip 1 turn every 10 turns). I think the reason is that when Robocode calculate CPU Constant, it concentrates the extreme math to single core, which trigger the boost (to 2.9GHz in my CPU), but when the battle is being run, there are several threads running (plus the CPU temp would be higher due to more calculation being done), so the boost is not triggered, hence the cpu run at base speed (2.0GHz in my case).

Personally I run my Robocode at 1.5x the original CPU Constant. I don't know which CPUs you guys are on, but I think this may be a problem, especially on RoboRumble clients. What do you think? Should I fire a bug report?

I don't have such an issue on my AMD box, but that's a very good point. Hmm... --Rednaxela 16:48, 12 November 2011 (UTC)

I also have an increased CPU constant, approx 1.5 times the original. Just because I still have a single core P4 and sometimes I want to do something without stopping my client. It does not seem to hurt anyway.

I'm new to robocode, and the learning curve is quite steep.

To phrase that another way, at one point my robot was locking on quite nicely to other robots, but subsequent versions (and prior versions) never appear to do anything sensible.

I'm an experienced programmer with lots of C and a bit of Java under my belt, so it's not the programming I'm struggling with.

I can get help with the specific physics questions (how do you get the angle between two headings? for example), so it's not that either.

I really just need someone who I can fire off a question "what does this do?" or "how does this work?" and get a simple response or a link to a wiki page.

I think if some sort of "big brother" mentorship programme were set up, a lot of people who would otherwise be put off by the massive learning curve might be encouraged to join in. More robots = more challenge = more fun. Right? :)

Until such a programme is set up, is there anybody out there who'd like to take a newbie under their wing? Please? :)

I would say just make yourself at home on the wiki and post all the questions you like. You'll probably get better / faster responses giving everyone a chance to answer them. Most of us watch Recent Changes and are happy to help. =) I'd also love to hear what kind of intro / tutorial pages would have been helpful to you, once you get your footing.

Welcome to the RoboWiki!

Yeah, just ask away. If you're not sure where to ask, just ask on your user page. It also helps if you keep some sort of documentation of what you're doing, it doesn't have to be fancy, but more like a changelog - it makes it easier for us to give suggestions. I'd think that the majority of the stuff is already here on the wiki, but knowing what to call it and where it is needs a bit of experience =). Fresh blood is always appreciated! So go wild with the questions.

Ok, I guess the format of the Wiki and the highly-conversational style are throwing me a bit. I wasn't expecting a response so quickly (or at all, for that matter).

I think a brief primer on the physics/maths calculations you'll need for robocode would be useful, eg:

- how to calculate the difference between two headings
- how to calculate the relative velocity of another bot vs your bot (don't know if this is used in any of the 'top' algorithms, but it feels like it could be useful to newbie bot authors)
- how/why to normalise headings to relative angles (I know the Utils class has this, but it would be useful for newbie bot developers to know how to do it themselves and why it's useful)
- how to calculate the distance between two headings (subtle difference between this and the first point)

If this already exists, could someone point me in the right direction?

I'm not sure if this is covered explicitly anywhere - I know for all of the geometry problems I run into I sketch it on paper then solve it traditionally.

That said, the difference between two headings is just (scan1 - scan2). You might want to use normalisation - either relative or absolute - to put it in the range you want.

On this wiki we generally refer to relative velocity in terms of its components - Lateral_Velocity and Advancing_Velocity. The pages for those explain how to calculate them, and yes, they are used in a lot of the more advanced algorithms =)

Relative normalisation is used for determining how far something is to the left or right - for instance, whether you should turn your gun left or right. It puts the angle between -Pi and +Pi (or -180 and +180). Absolute normalisation is usually used to figure out where something is 'relative to North' and gives a value between 0 and 2*Pi (or 0 and 360).

As to your last question, I'm not sure exactly what you're asking. Perhaps you want the absolute value of the heading difference? If so, take the relative normal angle first so you don't get the situation where one is on 355 degrees and the other 5 degrees, and the difference between them is 350 degrees instead of 10.

scan1-scan2 is over-simplified, if you want the -shortest- difference between the two headings, which is more useful, it should be: `360 - Math.max(scan1,scan2) + Math.min(scan1,scan2)` I think. Different when dealing in radians (obviously).

The last question is a little difficult to phrase, but no I'm not talking about the absolute value of the heading difference. I'm talking about calculating the distance between two points on two given headings. Using trigonometry. Eg "where is the bullet the robot I just scanned just fired? if he fired one", I know this specific example is impossible to model exactly, but for modelling best-guesses of enemies' guns I would imagine this kind of equation would come in handy.

Thanks for the links to Lateral and Advancing Velocities, it makes sense that they're used a lot in the more advanced algorithms, but those algorithms are all pretty much magic to me at the moment so I had absolutely no idea what is and isn't used.

I'm also not asking for specific answers to these questions, just asking if it might be wise to set up a wiki page that has some basic physics for the purposes of other newbies who don't have answers to the questions (I do, because my dad teaches A-level physics). But thanks for your answers nonetheless, as they did help clarify one or two points I wasn't sure about. :)

I'd take the difference, then normalise it relatively and take the absolute value.

As for the other one, you probably want to look at projecting a point from an origin location, a certain distance at a certain angle. If you look in the source of Raiko (or pretty much any other open source bot) you'll see the 'project' function. Once you have the new location of the point, you can calculate the distance the normal way, sqrt((x1-x2)^2 + (y1 - y2)^2).

Oh, and if you want to have a starting point for more advanced algorithms, I suggest Pattern_Matching. It's what I started with, and it makes a good introduction =)

I have a virtual gun that fires a virtual bullet, for some reason it's just slightly off when i actually fire.

What's the proper way to align and fire? I think my timing is just off.

I would guess this is the result of the Robocode idiosyncrasy where a bullet is fired before the gun is turned (so if you do setTurnGunRightDegrees(10), setFire(3), execute(), the bullet is fired before the gun is turned right 10 degrees). So your actual aim is probably the aim from the previous turn, while your predicted is from the current turn.

Well... can't really tell without more information what's wrong, but my first guess about what's wrong, is that perhaps you're not accounting for how within a tick, firing happens before gun turning does. The angle you fire at when you call setFire() is the angle resulting from the prior tick's setTurnGun() type call.

Yeah that's correct, the setFire is from the last tick.

What's a typical pattern for robocode as to code placement? I'm currently placing the gun turning code in the while true loop and the firing code in onScannedRobot

and it's wrapped with if (getGunHeat() == 0.0)

Should I change that layout? (also add && getGunTurnRemaining() == 0.0 to the fire wrap?)

Using onScannedRobot or run is totally just a matter of preference - for 1v1 it won't make any difference, really. It could also be an off-by-1 error in the bullet source location - it should be your location on the tick you called setFire. Or your target angle was farther than your gun could move during that tick, in which case the getGunTurnRemaining == 0 check would solve it.

I know if i combined the 2 logics in 1 function, the code would fail (for me at least) Nevermind i figured it out.

(Also Voidious: I'm testing my bot against yours now because it has pretty debugging graphics and I can see my weaknesses :P Also I perform better against your bot (diamond) if i don't fire :P)

Also, am I suppose to, with my virtual guns, determine the fire direction using last tick's information, since gun turns after bullet fires...

Right now this would f with my simulated hit rate, as sometimes a bullet might hit but not a virtual bullet, or vice versa.

Yep, you should, though the impact is probably quite minor.

Hm. Even last turn's angle doesn't match with the actual fired one. Idk what's going on, also I think the virtual bullets also hits better..

Anyway to compensate the gun turn after the bullet fire?

My bullets were not lined up either, until in March this year, I finally solved the problem with GresSuffurd 0.2.28. It turned out that when using the estimated bearing of the next tick (firing tick) position iso the bearing this tick (aiming tick), my real bullets indeed lined up with my (correct) virtual bullets. It gained me 0.2 APS, but I reached spot #11 with slightly misaligned bullets, so it is really not that important. Also keep in mind you have to aim at the opponents next tick position.

Wait i'm not sure if i understand what you mean by the next tick's position. How do I accomplish that?

Here's what I roughly have:

   while (true){
       if (getGunHeat() == 0.0){
           fireVirtualBullet(enemyCurrentAbsoluteBearing); // Just use Head on targeting as an example because it's simple
           fire(2);
       }
   
       turnGunRightRadians(enemyRelativeGunHeading);
   }

I know this would be wrong. I just don't know how to fix it =S

He means something like:

Point2D.Double myNextLocation = project(myLocation,getVelocity(),getHeadingRadians());
Point2D.Double enemyNextLocation = project(enemyLocation,e.getVelocity(),e.getHeadingRadians());
double nextAbsBearing = absoluteBearing(myNextLocation,enemyNextLocation);

I've tried this, and using it to predict the enemy location didn't help me, although it did help for my own location. I think it depends on the way you define wave hits and starting locations in your gun. In DrussGT I wait until my gun-turn remaining at the beginning of the tick is 0, then fire. I put my bullet on the wave from last tick. As long as you make the same assumptions everywhere it should be ok.

Yeah that doesn't help me either, predicting my next location and then aiming via that doesn't make it line up either. I also wait until gun turn is complete.... Still not aligning..

Also, how does bullets collision work? I thought it's a line segment that's between last tick's location and this tick's location (length of the velocity). Whatever the line segment intersect will be collided (other bullet lines or robots)

Maybe try staying still while shooting to see if that is the problem? If it still doesn't line up, it is some sort of gun alignment issue.

Yes, that is how bullet collisions work. Maybe take your last aim and align the bullet to that? What I do is mark my previous wave as having a bullet the moment setFireBullet() returns a non-null result.

Can I save data between rounds in the static variables of other classes other than my main robot class?

Yep. Anything that's static will stick around in any class.

Personally, I model most of my stuff so the main robot class has objects that are static (gun, movement, etc) and then everything else is non-static in those classes, but you can model it however you'd like.

Yes.

How is the while (true) loop actually broken down? Does robocode executes the code there 1 iteration per turn? Or..?

Generally, yes - when you call execute(), the Robocode engine processes one tick, including firing all the events on your bot, and then your run() method continues executing. So most of us have an infinite loop that calls execute() at the end, and each iteration is one tick.

But there's no magic to it - you could have a run method that goes:

public void run() {
  turnRight(20);
  ahead(100);
  fire(3);
}

And that would be perfectly valid. Or you could call execute() every third iteration of your loop. In Dookious, my run method used to have a loop that was while (notWonYet) ..., then a victory dance.

The timing thing for me is very confusing...

For example, if i want to fire at a certain angle, i have to rotate to it.. by the time i do.. i have another angle... which requires more rotation.. etc..

Same thing for turning the robot and going ahead.. I never know how to correctly time them. (Effectively stuck)

For gun aiming, see Robocode/Game_Physics#Firing_Pitfall. This can cause your aim to be a tick behind. I think most robots don't worry about it. But if you do worry about it, what I do is predict robot positions 1 tick into the future and use that for aiming. It's not exact, but works well enough for me.

Just installed LiquidThreads... Hope we all dig it. =)

We might!

Liquid threads are kind of better, but still not ideal. My main concern is that this still requires you to go to different pages, some are difficult to get to (have to know it specifically or get refered). For example, if someone were to ask a question/start a discussion on certain type of targeting etc.

Personally I think a forum works the best, as it can break things down into different categories and list everything out in a manageable fashion.

The Facebook group is good, but it lacks the community involvement, in my opinion.

Google+ seems cool, but I can't sign up for it with my Google Apps account..

... and who uses yahoo? :P

That's what the Special:RecentChanges is for - you can see modifications made anywhere on the wiki. Questions can be asked on the person's homepage and moved later, if necessary.

It will take a while to get used to. But there is no need to diff the discussion pages anymore. Neither convert local times to UCT every time I write something. Nice work.

Just doing 4 tildas (~) will automatically do a UTC timestamp, plus signature.

I have only one complain. LiquidThreads is polluting the Recent Changes page.

Ultimatebuster: With regards to a forum, personally the problem I would have with a traditional one, is that conversations are often with regards to a specific concept that either has or should have it's own wiki page anyway. The tight linkage between pages and talk pages encourages cross-pollination between the two sides, with discussion inspiring wiki pages and wiki pages inspiring discussion. Plus, I feel that the categories that would be created in a normal forum would be too broad for robocode and cronological sorting within such large groups too limiting.

A forum would be much more open for beginners to ask questions though. you shouldn't try to put everything into categories but just leave it to different threads in topics. --Peltco 06:15, 5 September 2011 (UTC)

Maybe it would make sense to have a page using liquidthreads which is specifically for asking questions when a specific page is not known? Perhaps do something like prominently link it from the main page, or even embed it?

Well, although beginners may not know, but I believe with our not-so-large community you can ask questions on almost any talk page, and if it seems inappropriate, someone will move the conversation to the right place. I really think we should have a bot that post welcome message to user, since IIRC it tells that you can ask question on your talk page.

Basically reduce the amount of data from the post that is set in the recent changes area. Lots of it has been wrapping, and that makes it harder to read. If possible half of what it has now. If possible even a "ABC has replied to thread XYZ". ;)

Personally, I think with the LiquidThread installed, every talk from old wiki should be put into the Archived talk namespace, or discussion header. My main reason is that discussion from old wiki would be uing old-style link, and I don't know how to programme a wikibot to edit a LiquidThread (plus my old converting code would work with the discussion header without modification)

I don't like leaving conversations in the discussion header, since it pushes the LiquidThreads stuff way down the page and I don't think that's what he header is for. I think moving to Archived talk is appropriate in most places, and you can just link to it in the header (like I did in Talk:Main Page).

I'm not sure how to deal with current conversations on the new wiki. I don't want them in the header. Archiving them is OK in most places, and maybe we could do it with a bot, but it feels pretty drastic to do it across the whole wiki. I wish I could just convert them to LiquidThreads conversations...