Introduction

The Quantum Katas are a series of self-paced tutorials aimed at teaching you elements of quantum computing and Q# programming at the same time.

Each kata is a separate project which includes:

• A sequence of tasks on the topic progressing from trivial to challenging. Each task requires you to fill in some code; the first task might require just one line, and the last one might require a sizable fragment of code.
• A testing framework that sets up, runs and validates your solutions. Each task is covered by a unit test which initially fails; once the test passes, you can move on to the next task!
• Pointers to reference materials you might need to solve the tasks, both on quantum computing and on Q#.
• Reference solutions, for when all else fails.

🆕 The Quantum Katas are now available as Jupyter Notebooks! See index.ipynb for the list of all Kata Notebooks and instructions on running them online.

Table of Contents

• List of Katas
• Running the Katas as Jupyter Notebooks
• Running the Katas Locally
  • Downloading the Quantum Katas
  • Running a kata as a Q# project
  • Running kata tests
  • Running the Katas locally with Docker
• Contributing
• Code of Conduct

List of Katas

Each kata covers one topic. Currently covered topics are:

Quantum computing concepts

• Basic quantum computing gates. This kata focuses on main single-qubit and multi-qubit gates used in quantum computing.
• Superposition. The tasks focus on preparing a certain superposition state on one or multiple qubits.
• Measurements. The tasks focus on distinguishing quantum states using measurements.
• Joint measurements. The tasks focus on using joint (parity) measurements for distinguishing quantum states and performing gates.

Simple algorithms

• Teleportation. This kata walks you through the standard teleportation protocol and several variations.
• Superdense coding. This kata walks you through the superdense coding protocol.
• Deutsch–Jozsa algorithm. This kata starts with writing quantum oracles which implement classical functions, and continues to introduce the Bernstein–Vazirani and Deutsch–Jozsa algorithms.
• Simon's algorithm. This kata introduces Simon's algorithm.

Grover's algorithm

• Grover's algorithm. This kata introduces Grover's search algorithm and writing quantum oracles to be used with it.
• Solving SAT problems using Grover's algorithm. This kata continues the exploration of Grover's search algorithm, using SAT problems as an example. It covers implementing quantum oracles based on the problem description instead of a hard-coded answer and using Grover's algorithm to solve problems with unknown number of solutions.
• Solving graph coloring problems using Grover's algorithm. This kata continues the exploration of Grover's search algorithm, using graph coloring problems as an example.

Entanglement games

• CHSH game.
• GHZ game.
• Mermin-Peres magic square game.

Miscellaneous

• Phase estimation. This kata covers phase estimation algorithms.
• Bit-flip error correcting code. This kata introduces a 3-qubit error correcting code for protecting against bit-flip errors.
• Unitary Patterns*. This unusual kata offers tasks on implementing unitaries with matrices that follow certain patterns of zero and non-zero elements.

Running the Katas as Jupyter Notebooks

The Quantum Katas are now available as Jupyter Notebooks! See index.ipynb for the list of all Kata Notebooks and instructions on running them online.

Running the Katas Locally

To use the Quantum Katas locally, you'll first need to install the Quantum Development Kit, available for Windows 10, macOS, and Linux. Please see the install guide for the Quantum Development Kit if you do not already have the Quantum Development Kit installed.

A quick reference sheet for Q# programming language is available here.

Downloading the Quantum Katas

If you have Git installed, go on and clone the Microsoft/QuantumKatas repository. From your favorite command line:

$ git clone https://github.com/Microsoft/QuantumKatas.git

TIP: Both Visual Studio 2017 and Visual Studio Code make it easy to clone repositories from within your development environment. See the Visual Studio 2017 and Visual Studio Code documentation for details.

Alternatively, if you don't have Git installed, you can manually download a standalone copy of the katas from https://github.com/Microsoft/QuantumKatas/archive/master.zip.

Running a kata as a Q# project

Each individual kata is placed in its own directory as a self-contained Q# solution and project pair. For instance, the BasicGates kata is laid out as below.

QuantumKatas/
  BasicGates/
    README.md                  # Instructions specific to this kata.
    .vscode/                   # Metadata used by Visual Studio Code.
    BasicGates.sln             # Visual Studio 2017 solution file.
    BasicGates.csproj          # Project file used to build both classical and quantum code.

    Tasks.qs                   # Q# source code that you will fill as you solve each task.
    Tests.qs                   # Q# tests that verify your solutions.
    TestSuiteRunner.cs         # C# source code used to run the Q# tests.
    ReferenceImplementation.qs # Q# source code containing solutions to the tasks.

To open the BasicGates kata in Visual Studio 2017, open the QuantumKatas/BasicGates/BasicGates.sln solution file.

To open the BasicGates kata in Visual Studio Code, open the QuantumKatas/BasicGates/ folder. Press Ctrl + Shift + P (or ⌘ + Shift + P on macOS) to open the Command Palette. Type "Open Folder" on Windows 10 or Linux or "Open" on macOS.

TIP: Almost all commands available in Visual Studio Code can be found in the Command Palette. If you ever get stuck, press Ctrl + Shift + P (or ⌘ + Shift + P on macOS) and type some letters to search through all available commands.

TIP: You can also launch Visual Studio Code from the command line if you prefer:

$ code QuantumKatas/BasicGates/

Running kata tests

Once you have a kata open, it's time to run the tests using the instructions below. Initially all tests will fail; do not panic! Open the Tasks.qs file and start filling in the code to complete the tasks. Each task is covered by a unit test; once you fill in the correct code for a task, rebuild the project and re-run the tests, and the corresponding unit test will pass.

Visual Studio 2017

1. Build solution.
2. Open Test Explorer (found in Test > Windows menu) and select "Run All" to run all unit tests at once.
3. Work on the tasks in the Tasks.qs file.
4. To test your code changes for a task, rebuild solution and re-run all unit tests using "Run All" or the unit test which covers that task by right-clicking on that test and selecting "Run Selected Tests".

Visual Studio Code

1. Press Ctrl + ` (or ⌘ + ` on macOS) to open the integrated terminal. The terminal should already start in the kata directory, but if not, use cd to navigate to the folder containing the *.csproj file for the kata.
2. Run dotnet test in the integrated terminal. This should automatically build the kata project and run all unit tests; initially, all unit tests should fail.
3. Work on the tasks in the Tasks.qs file.
4. To test your code changes for a task, run dotnet test again.

For convenience, we also provide a tasks.json configuration for each kata that allows Visual Studio Code to run the build and test steps from the Command Palette. Press Ctrl + Shift + P (or ⌘ + Shift + P on macOS) to open the Palette and type "Run Build Task" or "Run Test Task," then press Enter.

Running the Katas locally with Docker

You can use the included Dockerfile to create a docker image with all the necessary libraries to run the Katas from the command line or Jupyter.

The first step is to install Docker.

To build the docker image and tag it katas:

docker build -t katas .

To run the image in the container named katas-container with interactive command-line and redirect container port 8888 to local port 8888 (needed to run jupyter):

docker run -it --name katas-container -p 8888:8888 katas /bin/bash

From the corresponding container command line, you can run the C# version of the BasicGates kata using:

cd ~/BasicGates/
dotnet test

To start Jupyter Notebook within the image for the BasicGates kata, use:

cd ~/BasicGates/ && jupyter notebook --ip=0.0.0.0 --no-browser 

Once Jupyter has started, you can open in your browser the kata in notebook format (you will need a token generated by Jupyter when it started on the previous step):

http://localhost:8888/notebooks/BasicGates.ipynb

To escape a docker container without killing it (daemon mode):

Ctrl+P, Ctrl+Q

To re-enter the existing katas-container (in daemon mode):

docker attach katas-container

Once you're done, to remove the katas-container:

docker rm --force katas-container

Contributing

This project welcomes contributions and suggestions. For details, see How Can I Contribute?

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.