COMP1100 Assignment 3, Semester 2 2023

In this assignment, you will develop a software agent or AI bot that plays a board game called Sushi Go. We have implemented the rules of the game for you. Your task is to decide how is best to play.

Sushi Go is a card drafting game where players compete to build collections of sushi-themed cards that score the most points. This delightful game was designed by Phil Walker-Harding and published by Gamewright. For the purposes of this assignment, we have made some modifications to the rules.

This assignment is worth 15% of your final grade.

Deadline: Sunday 29th of October, 2023, at 11:00pm Canberra time sharp

Note: Late submissions will not be marked unless you have an approved extension.

We highly recommend committing your work as you go, and pushing regularly. Do not wait until you are finished to commit and push for the first time, as you run the risk of missing the deadline and having nothing submitted. An unfinished assignment is worth more than no assignment.

Overview of Tasks

This assignment is marked out of 100.

As with assignment 2, code that does not compile will be penalised heavily. This means that both the commands cabal v2-run game (with sensible arguments) and cabal v2-test must run without errors. If either command fails with an error, a significant mark deduction will be applied. If you have a partial solution that you cannot get working, you should comment it out and write an additional comment directing your tutor’s attention to it. You are also welcome to ask questions about error messages in drop-ins or on Ed.

If marks are deducted for warnings, they will only be from warnings in AI.hs and AITests.hs.

To help you ensure your submitted code is compiling, we’ve added a Continuous Integration (CI) script to this assignment. This will check that your code compiles, and mark any commit that fails with a red x on the commit, as shown below. You need to ensure that your latest commit on submission displays a green tick. You will also need to separately check that cabal v2-test succeeds on your own computer, because our CI is only set up to check cabal v2-run game.

Getting Started

1. Fork the assignment repository and create a project for it in VS Code/Codium, following the same steps as in Lab 2. The assignment repository is at

https://gitlab.cecs.anu.edu.au/comp1100/2023s2/studentfiles/asst3-1100_s2_2023.

1. Add our version of the repository as a remote called upstream. This allows us to provide additional fixes in the unlikely case that they are required. You do this by doing the following:

   • Go to the command palette in VSCode (or VSCodium) by pressing Ctrl + Shift + p.

   • Type git remote.

   • Click Git: Add Remote.

   • Enter upstream into the box for the remote name.

   • Put the following URL as the remote url: https://gitlab.cecs.anu.edu.au/comp1100/2023s2/studentfiles/asst3-1100_s2_2023.git.

Overview of the Game

The aim of Sushi Go (and our restricted version) is to collect cards (representing dishes) to make the highest-scoring (most delicious) meal possible. There are two players: Player 1 (Player1) and Player 2 (Player2).

There is a deck of cards which consists of the following:

At the start of the game the cards are shuffled and each player is dealt 20 cards each. (Note: As the original deck has more than 40 cards, the set of cards in play each game differ).

There are four collections of cards, the hand and the cards for each player. Player1’s hand denotes the cards that the player is to chose from. While Player1’s cards are the ones Player1 had already selected. Similarly, Player2’s hand denote what player 2 selects from and their cards are the cards that the player had already selected.

Thus when the game is starting, both players’ cards would be empty, while they would have a selection of 20 cards in their hand.

First player 1 chooses a single card from their hand of cards to keep. After placing the selected card, Player 2 does the same. After Player 2’s turn, both players swap hands and keep going. The game is over when both players’ hands are empty. The winner is the person whose cards are worth the most points, according to the scoring rules below.

The Cards

Nigiri

Nigiri(Nigiri Int) is your basic meal, and is worth the number of points in its argument (between 1 and 3, inclusive). It is more delicious if you add Wasabi.

Wasabi

Wasabi (Wasabi (Maybe Card)) makes Nigiri taste better! The next Nigiri that you take will be worth triple the points (for example Wasabi (Nigiri 2) will be worth $2\times3 =6$ points). If you take a Wasabi but do not later get a Nigiri to put on it, the Wasabi card will have no effect, so pay attention to the order in which you take cards.

Dumplings

Dumplings are delicious! The more you have the more you want! They score depends on how many you have

Eel

Eel (Eel) tastes terrible when you first try it, but you grow to like it after that.

Tofu

Tofu (Tofu) is great initially, but after a point it starts to make you sick!

Tempura

Tempura (Tempura) is amazing! But you have to have it in pairs. Each pair is worth 5 points.

Tea

Tea (Tea) gives your meal that amazing ending that you were craving! At the end of the round each tea card will be worth the maximum number of cards you have of a certain type.

• Note that if you have Wasabi (Nigiri 1) it counts as both a Wasabi and a Nigiri
• If you have more tea cards than other cards, then each tea card will be worth the count of tea cards.
• For example if we have: Nigiri 1, Wasabi Nothing, Wasabi (Nigiri 1), Dumpling, Wasabi (Nigiri 2), Tea, this will count as 3 Wasabi, 2 Nigiri 1, 1 Nigiri 2, 1 Dumpling, 1 Tea. Thus indicating that the tea card will be worth 3 points.

(This is slightly different from the original rules.)

Temaki

With Temaki (Temaki), you wouldn’t want anyone else to have it! At the end of the game, the player with the most temaki will get 4 points, while the player with the least will get (-4) points. If both players have the same amount, neither player will be awarded any points.

Initial set up

As mentioned above, each player will be dealt 20 cards. There will be no cards. (Player1 cards and Player2 cards are empty)

Player1 would be first to make a move.

Overview of the Repository

Most of your code will be written in src/AI.hs, but you will also need to write tests in src/AITests.hs.

Other Files

• src/SushiGo.hs implements the rules of SushiGo. You should read through this file and familiarise yourself with the data declarations and the type signatures of the functions in it, as you will use some of these to analyse the game states. You do not need to understand how the functions in this file work in detail. You do not need to change or implement anything in this file.

• src/SushiGoTests.hs implements some unit tests for the game. You are welcome to read through it.

• src/AITests.hs is an empty file for you to write tests for your agent.

• src/Testing.hs is a simple test framework similar to the one in Assignment 2. However, it has been extended so that you can group related tests together for clarity.

• src/Dragons contains all the other code that makes the framework run. You do not need to read or understand anything in this directory. Here be dragons! (On medieval maps they drew pictures of dragons or sea monsters over uncharted areas.) The code in those files is beyond the areas of Haskell which this course explores.

• Setup.hs tells cabal that this is a normal package with no unusual build steps. Some complex packages (that we will not see in this course) need to put more complex code here. You are not required to understand it.

• comp1100-assignment3.cabal tells the cabal build tool how to build your assignment. We will discuss how to use cabal below.

• .ghcid tells the ghcid tool which command to run, which is what supplies VSCodium with error highlighting that automatically updates when you save a file.

• .gitignore tells git which files it should not put into version control. These are often generated files, so it doesn’t make sense to place them under version control.

Overview of Cabal

As before, we are using the cabal tool to build the assignment code. The commands provided are very similar to last time:

• cabal v2-build: Compile your assignment.

• cabal v2-run game: Build your assignment (if necessary), and run the test program. We discuss the test program in detail below, as there are a number of ways to launch it.

• cabal repl comp1100-assignment3: Run the GHCi interpreter over your project so you can test functions interactively. It’s a good idea to run a cabal v2-clean before you run the above.

• cabal v2-test: Build and run the tests. This assignment is set up to run a unit test suite, and as with Assignment 2 you will be writing tests. The unit tests will abort on the first failure, or the first call to a function that is undefined.

• cabal v2-haddock: Generate documentation in HTML format, which you can read with a web browser. This might be a nice way to read a summary of the game module, but it also documents the Dragons modules which you can safely ignore.

• cabal v2-clean: Cleans up the temporary files and build artifacts stored in the dist-newstyle folder.

You should execute these cabal commands in the top-level directory of your project: comp1100-assignment3 (i.e., the directory you are in when you launch a terminal from VSCodium).

Overview of the Test Program

To run the test program, you need to provide it with command line arguments that tell it who is playing. This command will let you play against the current "default" AI bot. Before you replace this with your own bot, the default will be firstLegalMove :

cabal v2-run game -- --p1 human --p2 ai

using ai to get the default ai is part of how we mark your assignment, so it is vital that you update your default bot to be whatever you want to be marked!

For instance if you want your minimax to be the bot that is marked, you should change your code to look like this

ais :: [(String, AI)]
ais = [ ("firstLegal", NoLookahead firstLegal)
      , ("greedy", NoLookahead greedy)
      , ("default", WithLookahead minimax)
      ]

Note that there should be only one default ai.

To play against your ai, you need to type in the letters next to a card to pick it from your hand.

To play with a differently named AI, say the one you have named "greedy, use:

cabal v2-run game -- --p1 human --p2 ai:greedy

In general, the command to run the game looks like this:

cabal v2-run game -- ARGS

Replace ARGS with a collection of arguments from the following list:

• --seed INT: Sets a seed for how the deck would be shuffled, the INT is to be a positive number. This would allow you to check your performance on a certain game setup.

• --timeout DURATION: Change the amount of time (in decimal seconds) that AI functions are given to think of a move (default = 4.0). You may want to set this to a smaller number when testing your program, so that things run faster.

• --debug-lookahead: When an AI is done thinking, print out how many moves ahead it considered, and the candidate move it came up with at each level of lookahead. The first item in the printed list is the move it came up with at lookahead 1, the second item is the move it came up with at lookahead 2, and so on.

• --ui text: Show the game in the terminal.

• --ui json: Run a non-interactive game (i.e., AI vs. AI, or AI vs network), and output a report of the game in JSON format. You probably won’t have a use for this, but it’s documented here for completeness.

• --host PORT: Listen for a network connection on PORT. You only need this for network play (see below).

• --connect HOST:PORT: Connect to someone else’s game. You only need this for network play (see below).

• --p1 PLAYER: Specify the first player. Required.

• --p2 PLAYER: Specify the second player. Required.

The PLAYER parameters describe who is playing, and can take one of the following forms:

Network Play

Network play is provided in the hope that it will be useful, but we are unable to provide support for this feature, or diagnose problems related to tunnelling network connections between computers.

The assignment framework supports network play, so that you can test agents against each other without sharing code. One machine must host the game, and the other machine must connect to the game. In the example below, machine A hosts a game on port 5000 with the agent crashOverride as player 1, then machine B connects to the game, providing the AI chinook as player 2:

# On Machine A:
cabal v2-run game -- --host 5000 --p1 ai:crashOverride --p2 network

# On Machine B (you'll need Machine A's external IP address somehow):
cabal v2-run game -- --connect 198.51.100.66:5000 --p1 network --p2 ai:chinook

Under the bonnet, the network code makes a single TCP connection, and moves are sent over the network in JSON. You will need to set up your modem/router to forward connections to the machine running your assignment. A service like ngrok may help, but as previously mentioned we are unable to provide any support for this feature.

Main Task: Sushi Go AI (55 Marks)

Implement an AI (of type AI, defined in src/AI.hs). There is a list called ais in that file, and we will mark the AI you call "default" in that list. This list is also where the framework looks when it tries to load an AI by name.

We will test your AI’s performance by comparing it to implementations written by course staff, using a variety of standard approaches. Its performance against these AIs will form a large part of the marks for this task.

It is vital that you indicate one AI as "default", otherwise we will not know which one to mark. To indicate an AI as "default", you must have a (String, AI) pair in the ais list of AIs in src/AI.hs where the String is precisely "default".

Understanding the AI Type

The AI type has two constructors, depending on whether you are implementing a simple AI that looks only at the current state, or a more complicated AI that performs look-ahead.

The NoLookahead constructor takes as its argument a function of type GameState -> Move. That is, the function you provide should look at the current state of the game and return the move to play. This constructor is intended for very simple AIs that do not look ahead in the game tree. As such, this function should never run for more than a moment at a time, but nevertheless, it is also subject to the timeout of 4 seconds.

The WithLookahead constructor takes as its argument a function of type GameState -> Int -> Move. The Int parameter may be used for any purpose, but we anticipate that you will use it to represent how many steps you should try to look ahead in the game tree. The assignment framework will call your function over and over, with look-ahead 1, then 2, then 3, etc., until it runs out of time. The framework will take the result of the most recent successful function call as your AI’s best move. If your AI does not return a move in time, the program will stop with an error.

Getting Started

This is a very open-ended task, and it will probably help if you build up your solution a little at a time. We suggest some approaches below.

Your AI should inspect the Turn within the Game to see whose turn it is. You may call error if the Turn is GameOver - your AI should never be called on a finished game. Your AI can then use the Player value and otherPlayer function to work out how to evaluate the board.

You may also assume that we will only ever call your AI if there is a legal move it can make (when the player’s hand is never empty). In particular, this means that we will not deduct marks for assuming that a list of legal moves is non-empty (e.g., you used the head function). Note that gratuitous use of head and tail is still poor style. Note that, in general, you cannot make this assumption about GameStates you have generated within your AI function.

First Legal Move

The simplest AI you can build is one that makes the first legal move it can. We have provided this for you, so you can see what a simple AI looks like.

Interlude: Heuristics

Heuristic functions are discussed in the lecture on game trees. We expect the quality of your heuristic function—how accurately it scores game states—to have a large impact on how well your AI performs.

Greedy Strategy

“Greedy strategies” are the class of strategies that make moves that provide the greatest immediate advantage. In the context of this game, it means always making the move that will give it the greatest increase in heuristic. Try writing a simple heuristic and a greedy strategy, and see whether it beats your “firstLegalMove” AI. Bear in mind that in a game like this, firstLegalMove will not play terribly, as it still must capture when given the opportunity.

Interlude: Game Trees

To make your AI smarter, it is a good idea for it to look into the future and consider responses to its moves, its responses to those responses, and so on. The lecture on game trees may help you here.

Minimax

Greedy strategies can often miss opportunities that need some planning, and get tricked into silly traps by smarter opponents. The Minimax algorithm was discussed in the lecture on game trees and will likely give better performance than a greedy strategy.

Pruning

Once you have Minimax working, you may find that your AI explores a number of options that cannot possibly influence the result. Cutting off branches of the search space early is called pruning, and one effective method of pruning is called alpha-beta pruning as discussed in lectures. Good pruning may allow your search to explore deeper within the time limit it has to make its move.

Other Hints

• There are four main ways your AI can be made smarter:

  • Look-ahead: If your function runs efficiently, it can see further into the future before it runs out of time. The more moves into the future it looks, the more likely it will find good moves that are not immediately obvious. Example: at 1 level of look-ahead, a move may let you capture a lot of pieces, but at deeper look-ahead you might see that it leaves you open to a large counter-capture.

  • Heuristic: You will not have time to look all the way to the end of every possible game. Your heuristic function guesses how good a Game is for each player. If your heuristic is accurate, it will correctly identify strong and weak states.

  • Search Strategy: This determines how your AI decides which heuristic state to aim for. Greedy strategies look for the best state they can (according to the heuristic) and move towards that state. More sophisticated strategies like Minimax consider the opponent’s moves when planning.

  • Pruning: if you can discard parts of the game tree without considering them in detail, you can process game trees faster and achieve a deeper look-ahead in the allotted running time. Alpha-beta pruning is one example; there are others.

• Choosing a good heuristic function is very important, as it gives your AI a way to value its position that is smarter than just looking at current score. If there is only one copy of Sashimi in the game, you will never get the 3 copies to get 10 points, so the card is worth zero and you probably will not want to pick it. If you can complete the set, each card in the set is effectively worth a pretty-good 3+1/3 points.

• Do not try to do everything at once. This does not work in production code and often does not work in assignment code either. Get something working, then take your improved understanding of the problem to the more complex algorithms.

• As you refine your bots, test them against each other to see whether your changes are actually an improvement.

Unit Tests (10 Marks)

As with Assignment 2, you will be expected to write unit tests to convince yourself that your code is correct. The testing code has been extended from last time—src/Testing.hs now allows you to group tests into a tree structure. As before, you run the tests using cabal v2-test.

Your Task

Add tests to src/AITests.hs to test your AI.

Hints

• Most of the hints from Assignment 2 apply here. Re-read those.

• If a function is giving you an unexpected result, try breaking it into parts and writing tests for each part. This helps you isolate the incorrect parts, and gives you smaller functions to fix.

• If your function has subtle details that need to be correct, think about writing tests to ensure those details do not get missed as you work on your code.

Coding Style (10 Marks)

As you write increasingly complex code, it is increasingly important that the code remains readable. This saves wasted effort understanding messy code, which makes it easier to think about the problem and your solution to it.

If you wish, you know how, and you have a good reason, you may split your code into multiple modules. However this is not a requirement, and you will never be penalised for not doing so.

You MUST NOT edit any of the files in the framework (with the obvious exceptions of AI.hs and AITests.hs. You may also edit SushiGoTests.hs but there should be no reason to.)

Note: We will not regard code that is used by any of your AIs as ‘dead code’, even if it not used by your submitted default AI. But we will only mark your default AI.

Your Task

Ensure that your code is written in good Haskell style.

Technical Report (COMP1100: 25 marks)

You should write a concise technical report explaining your design choices in implementing your program. The maximum word count is 1500. This is a limit, not a quota; concise presentation is a virtue.

Once again: This is not a required word count. They are the maximum number of words that your marker will read. If you can do it in fewer words without compromising the presentation, please do so.

Your report must be in PDF format, located at the root of your assignment repository on GitLab and named Report.pdf. Otherwise, it may not be marked, or will be marked but with a penalty. You should double-check on GitLab that this is typed correctly.

The report must have a title page with the following items:

• Your name;

• Your laboratory time and tutor; and

• Your university ID.

Content and Structure

Your audience is the tutors and lecturers, who are proficient at programming and understand most concepts. Therefore you should not, for example, waste words describing the syntax of Haskell or how recursion works. After reading your technical report, the reader should thoroughly understand:

1. What problem your program is trying to solve;
2. The reasons behind major design choices in it; as well as
3. How it was tested.

Your report should give a broad overview of your program, but focus on the specifics of what you did and why.

Remember that the tutors have access to the above assignment specification, and if your report only contains details from it then you will only receive minimal marks. Below is a potential outline for the structure of your report and some things you might discuss in it.

Introduction

If you wish to do so you can write an introduction. In it, give:

• A brief overview of your program:

  • how it works; and

  • what it is designed to do.

• If you have changed the way the controls work, or added something that may make your program behave unexpectedly, then it would be worth making a note of it here.

This section is particularly relevant to more complicated programs.

Analysis of your Program

The purpose of this section is to describe your program to the reader, both in detail and at a high level.

Talk about what features your program actually has. We know what we asked for (the features in this document!), but what does your program actually let a user do? How does your program work as a whole?

How does it achieve this? Let us know how each individual function works and how they work together to solve particular design goals.

A successful report will demonstrate conceptional understanding of all relevant functions, and depicts a holistic view of program structure through discussion of what it is and hour it works.

Rationale and Reflection

The purpose of this section is to describe the design decisions you made while writing the program, to the reader.

Tell us the reasoning behind the choices you detailed above. Tell us the assumptions you made about user behaviour. Why did you solve the problems the way you did? Why did you write the functions you wrote? Did you make any other assumptions?

For example:

“I implemented the checkFirst helper function after reading this blog post (citing the post as a reference), claiming that users of quadrant based drawing programs virtually always draw their first shape in the top-right quadrant. Deciding to use this as my base assumption for user-behaviour, I decided to save on quadrant-dependent calculation of trigonometric ratios by always assuming the first shape is drawn in this quadrant. This in turn meant I needed a function to check if a shape was the first one drawn.”

This is a critical reflection not a personal one. You’re explaining the justification and reasoning behind the choices you made.

A successful report will give a thorough explanation of the process followed to reach a final design, including relevant reasoning and assumptions / influences.

In this section, you might also reflect on any conceptual or technical issues you encountered, particularly if you were unable to complete your program. Try to include details such as:

• theories as to what caused the problem;
• suggestions of things that might have fixed it; and
• discussion about what you did try, and the results of these attempts.

Testing

• How did you test individual functions?
  • Be specific about this - the tutors know that you have tested your program, but they want to know how.
  • Describe the tests that prove individual functions on their own behave as expected (i.e. testing a function with different inputs and doing a calculation by hand to check that the outputs are correct).
  • How did you test the entire program? What tests did you perform to show that the program behaves as expected in all (even unexpected) cases?
  • How did you test the quality of your AI’s play?

A successful report will demonstrate evidence of a process that checked most, if not all, of the relevant parts of the program through testing. Such a report would combine this with some discussion of why these testing results prove or justify program correctness.

Style

A successful report should have excellent structure, writing style, and formatting. Write professionally, use diagrams where appropriate but not otherwise, ensure your report has correct grammar and spelling.

This is a list of suggestions, not requirements. You should only discuss items from this list if you have something interesting to write.

Things to avoid in a technical report

• Line by line explanations of large portions of code. (If you want to include a specific line of code, be sure to format as described in the “Format” section below).

• Pictures of code, VSCodium or your IDE.

• Content that is not your own, unless cited.

• Grammatical errors or misspellings. Proof-read it before submission.

• Informal language - a technical report is a professional document, and as such should avoid things such as:

  • Unnecessary abbreviations (atm, btw, ps, and so on), emojis, and emoticons; and

  • Stories / recounts of events not relevant to the development of the program.

• Irrelevant diagrams, graphs, and charts. Unnecessary elements will distract from the important content. Keep it succinct and focused.

If you need additional help with report writing, the academic skills writing centre has a peer writing service and writing coaches.

Format

You are not required to follow any specific style guide (such as APA or Harvard). However, here are some tips which will make your report more pleasant to read, and make more sense to someone with a computer science background.

• Colours should be kept minimal. If you need to use colour, make sure it is absolutely necessary.

• If you are using graphics, make sure they are vector graphics (that stay sharp even as the reader zooms in on them).

• Any code, including type/function/module names or file names, that appears in your document should have a monospaced font (such as Consolas, Courier New, Lucida Console, or Monaco).

• Other text should be set in serif fonts (popular choices are Times, Palatino, Sabon, Minion, or Caslon).

• When available, automatic ligatures should be activated.

• Do not use underscore to highlight your text.

• Text should be at least 1.5 spaced.

Communication

Do not post your code publicly, either on Ed or via other forums. Posts on Ed trigger emails to all students, so if by mistake you post your code publicly, others will have access to your code and you may be held responsible for plagiarism.

Once again, and we cannot stress this enough: do not post your code publicly . If you need help with your code, post it privately to the instructors.

When brainstorming with your friends, do not share code. There might be pressure from your friends, but this is for both your and their benefit. Anything that smells of plagiarism will be investigated and there may be serious consequences.

Sharing ideas and sketches is perfectly fine, but sharing should stop before you risk handing in suspiciously similar solutions.

Course staff will not look at assignment code unless it is posted privately on Ed, or shared in a drop-in consultation.

Course staff will typically give assistance by asking questions, directing you to relevant exercises from the labs, or definitions and examples from the lectures.

Before the assignment is due, course staff will not give individual tips on writing functions for the assignment or how your code can be improved. We will help you get unstuck by asking questions and pointing you to relevant lecture and lab material. You will receive feedback on your work when marks are released.

Submission Advice

Start early, and aim to finish the assignment several days before the due date. At least 24 hours before the deadline, you should:

• Re-read the specification one final time, and make sure you’ve covered everything.

  • You have fully read and understand the entire assignment specification. See the “Overview of Tasks” section to check that you have completed all tasks.

• Confirm that the latest version of your code has been pushed to GitLab.

  • You can confirm that the latest version of your code has been pushed to GitLab by using your browser to visit https://gitlab.cecs.anu.edu.au/uXXXXXXX/asst3-1100_s2_2023, where XXXXXXX is your student number.

• Ensure your program compiles and runs, including the cabal v2-test test suite. Make sure you have a green CI tick on your latest commit in Gitlab

• Ensure your submission works on the lab machines. If it does not, it may fail tests used by the instructors.

• Proof-read and spell-check your report.

• Verify that your report is in PDF format, located at the root of your project.

• Verify that your report is in PDF format, located at the root of your project directory (not in src), and named Report.pdf. That capital R is important - Linux uses a case-sensitive file system. Otherwise, it may not be marked.

• Check that all work including your report is submitted by viewing your assignment repo on Gitlab.

We recommend that you do not wait until you are finished to commit and push your work. Commit and push as you work, to reduce the risk of submission errors at the last minute.