- lynkos/grovers-algorithm: Python (.py) and Jupyter notebook (.ipynb) implementations of Grover's Algorithm aka Quantum Search Algorithm for n qubits and m targets.

Important

This repository has accompanying blog posts on my blog!

Quantum Search Algorithm: Short, Twitter/X-inspired thread format
Quantum Search Algorithm (Full): Full explanation with additional details

These blog posts are much more readable and user-friendly than this repository by itself and . If you're interested in sharing or reading this repository as a blog post, please feel free to refer to the aforementioned links!

Anaconda OR Miniconda

Tip

If you have trouble deciding between Anaconda and Miniconda, please refer to the table below

Anaconda	Miniconda
New to conda and/or Python	Familiar with conda and/or Python
Not familiar with using terminal and prefer GUI	Comfortable using terminal
Like the convenience of having Python and 1,500+ scientific packages automatically installed at once	Want fast access to Python and the conda commands and plan to sort out the other programs later
Have the time and space (a few minutes and 3 GB)	Don't have the time or space to install 1,500+ packages
Don't want to individually install each package	Don't mind individually installing each package

Typing out entire Conda commands can sometimes be tedious, so I wrote a shell script (conda_shortcuts.sh on Gist) to define shortcuts for commonly used Conda commands.

Example: Delete/remove a conda environment named test_env

Shortcut command
```
rmenv test_env
```

Manually typing out the entire command

conda env remove -n test_env && rm -rf $(conda info --base)/envs/test_env

The shortcut has 80.8% less characters!

Verify that conda is installed
```
conda --version
```
Ensure conda is up to date
```
conda update conda
```
Enter the directory where you want the repository (grovers-algorithm) to be cloned
- POSIX
```
cd ~/path/to/directory
```
- Windows
```
cd C:\Users\user\path\to\directory
```
Clone the repository (grovers-algorithm), then enter (i.e. cd command) grovers-algorithm directory
```
git clone https://.com/lynkos/grovers-algorithm.git && cd grovers-algorithm
```
Create a conda virtual environment from environment.yml
```
conda env create -f environment.yml
```
Activate the virtual environment (grovenv)
```
conda activate grovenv
```
Confirm that the virtual environment (grovenv) is active
- If active, the virtual environment's name should be in parentheses () or brackets [] before your command prompt, e.g.
```
(grovenv) $
```
- If necessary, see which environments are available and/or currently active (active environment denoted with asterisk (*))
```
conda info --envs
```
  OR
```
conda env list
```

Tip

If you're unsure about which subsection(s) to follow, please refer to the table below

Visual Studio Code	Command Line
Beginner/User-friendly	Recommended if familiar with using terminals/shells/CLIs
GUI	CLI
Click a button to run program	Execute a command in terminal/shell/CLI to run program

Note

Although they both perform the same function, there's a discernable difference between grovers_algorithm.py and grovers_algorithm.ipynb. The former is a Python script, the latter is a Jupyter notebook.

Run grovers_algorithm.py

python src/grovers_algorithm.py

Command Line Arguments

Option	Type	Description	Default
`-H, --help`		Show help message and exit
`-T, --title <title>`	`str`	Window title	"Grover's Algorithm"
`-n, --n-qubits <n_qubits>`	`int`	Number of qubits	`5`
`-s, --search <search>`	`int`	Nonnegative integers to search for	`11 9 0 3` (i.e., { 11, 9, 0, 3 })
`-S, --shots <shots>`	`int`	Number of simulations	`1000`
`-f, --font-size <font_size>`	`int`	Histogram's font size	`10`
`-p, --print`	`bool`	Whether or not to print quantum circuit(s)	`False`
`-c, --combine`	`bool`	Whether to combine all non-winning states into 1 bar labeled "Others" or not	`False`

Open grovers_algorithm.py
Run grovers_algorithm.py: Click ▷ (i.e. Play button) in the upper-right corner

Open the Command Palette with the relevant keyboard shortcut
- Mac
```
⌘ + Shift + P
```
- Windows
```
CTRL + Shift + P
```
Search and select Python: Select Interpreter
Select the virtual environment (grovenv)
Open grovers_algorithm.ipynb
Confirm grovenv is the selected kernel
Run grovers_algorithm.ipynb by clicking Run All

Install ipykernel in the virtual environment (grovenv)
```
conda install -n grovenv ipykernel
```
Add the virtual environment (grovenv) as a Jupyter kernel
```
python -m ipykernel install --user --name=grovenv
```
Open grovers_algorithm.ipynb in the currently running notebook server, starting one if necessary
```
jupyter notebook src/grovers_algorithm.ipynb
```
Select the virtual environment (grovenv) as the kernel before running grovers_algorithm.ipynb