This is about an open world game in java where millions of units (special ships) are going to move from one planet to another.
I want to make any ship customizable by using and compounding it out of basic modules, the problem is I don't know how to represent all that information in an efficient way, but what I think is:
use an array of objects (one obj per ship) - but that doesn't seem to work.
make a few predefined types of ships, and represent the number of ships in a fleet with an int, but that would mean throwing away the whole idea of customizing the ships, uhm.
How could I resolve this?
It might be worth reading up on some design patterns, particularly the Flyweight Pattern. Some quick ideas off the top of my head would be to have one instance of each "base" ship and one instance of each of the parts that can be added. Then you can access these shared instances in each other ship. Things like ammo and health can be unique to each ship as they are simple numbers and won't take up nearly as much memory. It may take some thinking but I feel Flyweight is your best starting point. Good luck!
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I have a challenge that my teacher gave to beat an army of his soldiers on a 18x24 grid, with random obstacles placed on the board. The game is turn based and I have an army of 50 soldiers, each of which needs to either move or attack on their turn.
My problem is I only have access to creating a class of soldiers to fight in this environment. Currently I have a method that evaluates the board position by looking at how many soldiers there are left from each team and does yourTeam - enemyTeam to get the current score, and I have a method that will produce the legal moves for the soldier.
I want to know how I would create a reinforcement learning agent in Java with what I have access to. If you know any ways to do this or any resources that may help that would be great. Thank you for the help!
Java is not a good language for doing math heavy computation (which is what you will need to do for RL). You could attempt to implement the Q-Learning, value-iteration or policy-iteration algorithms but I would avoid doing anything with neural networks/modern deep RL approaches here as your work load will increase dramatically.
With regard to your problem, if you are to implement one of the old-school algorithms. Think about your state and action space. I have serious concerns about the size of your action space, even with a small number of moves for each solider (say 3 - attack, move up, move down) with 50 soldiers the action space will be very large - 50^3, even this many will be difficult to deal with, any more (even 4 or 5) will send you deep into some complex topics in RL.
Other problems are - defining a good reward signal, efficiently running (potentially millions) of simulated games.
The short answer is, this is not something to be taken lightly, it would be challenging and time consuming even for someone who has experience in the field and using Java is a no-no (Python is better). Given you probably don't have long to find a good solution, I would recommend trying a different approach - planning based maybe, or hard coding a reasonable strategy.
If you still want to go ahead and read up on the topic here are some good resources:
Reinforcement Learning an Introduction (Sutton & Barto) - any edition is fine
Selected chapters in Artificial Intelligence: A Modern Approach (Russel & Norvig)
Hope this helps and sorry it may not have been the answer you we hoping for!
I'm trying to store a list of different Enemies. Each Enemy has an origin and can only spawn in its Location of origin. Each enemy also has a difficulty and should be stored with enemies of the same difficulty.
I imagined it as a static 3D array of Enemies like this:
Enemy[mountain][2][5] = new Enemy("troll")
Where the fields are (from left to right) Location, difficulty, index.
Each location the player enters will populate an ArrayList of Enemies from this static array.
Is there a more efficient data structure to use in this scenario?
(This list will be hard-coded and should not be altered during the course of the program)
edit-
I was hoping to optimize the access time. This game will generate a number of locations, each one needing to randomly draw Enemies from the list based on their origin and difficulty.
As per request, I will put some more thought into the use case of this program. Once I have a proper solution I will update. (Thanks)
It is conceptually wise not a good idea.
You really do not worry about performance at this point. You worry about creating a useful, helpful object model that allows you to write elegant, easy-to-read and easy-to-enhance code.
Using a 3D-array achieves none of these goals.
In other words: you step back; and think hard about the "use cases" that need to access your Enemy objects. And coming from there, you decide if you should go with different Maps for example; or different Sets, ... instead of using a 3D as central "storage point".
Edit, given your comment: there are two sides here:
Arrays are very inflexible in Java. You can't change their size dynamically. And beyond that, they are really "ugly" to use: this going through "3 dimensions" might be convenient for a certain "ascess path"; but it could make other things very hard (like when searching for a certain enemy, then you have to do this 3-dim iteration stuff ... as said: ugly)
One should try to make designs that are "open" for changes that have a high rate of "taking place". Example: you have a fixed number of enemies today; but assuming your "game" works out for you; you will sooner or later (rather sooner) want to enhance it; for example by allowing dynamic add/removal of enemies. Then a lot of the code you wrote using the 3-D array ... would become a real obstacle.
Beyond that: yes, in a "game world", there should be one component that is responsible for keeping track of all elements in the game. But: how this component internally organizes things is more of an implementation detail. You should focus on putting "helpful" methods on that GameWorld first; or as I put it before: understand the ways how your code will need to access/iterate/search enemies to perform the game itself. And then you look into data structures that support these "use cases".
Finally: assuming that this is a learning exercise - you can still start with a 3d array. It will teach you a lot; I am merely pointing out: you would not do that in a more "real world" application; and if you go for this option, you will soon be confronted with certain limitations/obstacles; just by the nature of your solution.
What comes to mind for me is a map. The location is the key and the value would be a List of objects that represents the enemy and its location - let's call it an EnemyLocation object that contains an Enemy and its location (or you could change Enemy to contain its location which seems like a good idea, but I don't know your code). So, when a player enters the "mountain" region, you do something like enemies.get("mountain") and you get back a List of Enemy objects (or EnemyLocation objects)
So I'm making a game similar to Age of Empires 2. So far, what I've been doing is using an Applet and making an array of tiles (grid) to contain units and buildings. I feel that in the long run this is going to be inefficient. I'm sure there is a better way to do this, perhaps using GUI, but I'm not a very experienced programmer yet so I've resorted to this more primitive method. Is there a better, more efficient way to have tiles that contain characters and buildings on the map?
Thanks.
This is pretty much how I want it to look like:
An array of tiles should be fine - this is what is usually used to represent the map in a 2D game.
Note that you will probably want to distinguish between:
Map terrain tiles, where each square contains just one tile
Units / buildings / other game objects, where each square might contain multiple objects
For the terrain a single array is fine, with one tile in each position.
For the other objects, you need a way to store multiple objects in each square. An array with an ArrayList in each square can work - though you will probably want to leave nulls in all the squares that don't have any contents to avoid creating a lot of empty ArrayLists.
It's also useful to create a global collection of game objects so that you can iterate over all game objects and/or find a speciifc object quickly without searching the whole map. I typically use something like a HashMap for this, where the integer key is a unique ID for each game object.
It depends on what you consider to be the 'inefficient' part. If most of the array elements are going to be containing data, and you need to be able to look up that data quickly and easily, than arrays are certainly the best way to go. They're easy to understand, and the logic mikera described for storing data is a very good way to get started.
There are data structures that very big tile based games use for storing data. Most of those are optimized for 'sparse' graphs at the like. A sparse graph is one where most of the locations are empty, but a few of them have content. Very big world maps often have this qualit. If you're curious about these scenarios, then you should google "quad tree tiling".
But in general, if you're still learning development, stick to the array. Premature optimization is the root of all evil. :)
I want to implement a reinforcement learning connect four agent.
I am unsure how to do so and how it should look. I am familiar with the theoretical aspects of reinforcement learning but don't know how they should be implemented.
How should it be done?
Should I use TD(lambda) or Q-learning, and how do MinMax trees come in to this?
How does my Q and V functions work (Quality of action and Value of state). How do I score those things? What is my base policy which I improve, and what is my model?
Another thing is how should I save the states or statesXactions (depending on the learning algorithm). Should I use neural networks or not? And if yes, how?
I am using JAVA.
Thanks.
This might be a more difficult problem than you think, and here is why:
The action space for the game is the choice of column to drop a piece into. The state space for the game is an MxN grid. Each column contains up to M pieces distributed among the 2 players.This means there are (2M+1-1)N states. For a standard 6x7 board, this comes out to about 1015. It follows that you cannot apply reinforement learning to the problem directly. The state value function is not smooth, so naíve function approximation would not work.
But not all is lost. For one thing, you could simplify the problem by separating the action space. If you consider the value of each column separately, based on the two columns next to it, you reduce N to 3 and the state space size to 106. Now, this is very manageable. You can create an array to represent this value function and update it using a simple RL algorithm, such as SARSA.
Note, that the payoff for the game is very delayed, so you might want to use eligibility traces to accelerate learning.
I'm very new to Java and am not sure if I'm even allowed to ask questions of this nature here but I'll give it a shot. I want/need practice programming Java so I've decided on a rather large project that should be within my capabilities I've started building it and have created a player object with some properties like level,name,xp,health and items. The items are and array of 5 object objects (bear with me XD) now I'd like to know if I should create the rooms as objects as well or as seperate classes or functions?
The rooms will be only rooms in an abstract sense the game is fully text-based they will need to contain puzzles and objects a user can pick up or examine as well as enemies and such the narrative will also be contained in each one. The player will be able to "pick up" items in the room and add them to their inventory. As well as participate in textual comabt with enemies like : you hit monster for 2 damage, monster hits back for 3 etc.
Remember that this isn't going to be pretty it's for practice and I need to do it within Java.
Thanks in advance.
Your problem is related to the OOP concepts not to being a beginner in java, you should know more about OOP to think correctly before starting coding to put the correct OOP design for your program. since you are building this program in java you can start here.
For what I've understand from you question, you may want to have a Room Class, Containing the Room Properties and Functions.
From a high level, a good idea would be having a "Room" class, this would contain the Room Title, Description and any other room specific information (such as terrain type etc).
You could then create a multidimensional array of Room objects. One dimension being your X coordinate while the other your Y coordinate.
This way to "move" around all you need to do is track your location and either increment/decrement your X or Y based on the direction you moved.
You could extend it further doing something like generating a map of your surroundings as well. Each terrain type could be displayed as a different symbol (# for forest, ~ for water etc). It would be a simple approach to add something like this because all you need to do is get your top right/bottom left coordinate and loop through those coordinates building your map.