Tutorial 10

🐍 Python Virtual Environments

This guide will help you set up a Python Virtual Environment (PVE) on both:

• 💻 Your Mac
• ⚙️ The POWER cluster

By the end, you'll have an isolated and clean Python environment running smoothly on both machines. 🎯

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🍎 PVE on Your Mac

First, open your Terminal and install Homebrew, a package manager that makes software installation easy:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

👀 You'll be prompted to add some lines to your shell's PATH. Follow the on-screen instructions.

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🍺 Install GCC (includes gfortran)

This will be useful later, especially for scientific Python packages:

brew install gcc

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🐍 Install Micromamba

Micromamba is a fast and lightweight package and environment manager. Install it via Homebrew:

brew install micromamba

Once installed, you'll again be prompted to add Micromamba to your shell:

/opt/homebrew/opt/micromamba/bin/micromamba shell init -s zsh -p ~/micromamba

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🧙‍♂️ Make Your Life Easier with an Alias

To simplify usage, alias mamba to micromamba:

1. Open your zprofile file:

   vim ~/.zprofile

2. Add this line to the bottom:

   alias mamba="micromamba"

💡 Now you can use mamba commands on both your Mac and the POWER cluster with the same syntax!

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⚡ PVE on POWER

Let’s configure your virtual environment on the POWER cluster. 💪

🧾 Modify .bashrc

Add this line to the end of your .bashrc file:

module load mamba > /dev/null

Then apply the change:

source ~/.bashrc

✅ You’re now ready to create environments with Mamba on POWER!

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🏗️ Creating a Virtual Python Environment

Run the following command (replace <youraccountname> with your username):

mamba create --prefix /leeburton-data/<youraccountname>/envs/my_env python=3.8

🎯 It’s important to use Python 3.8 — later tools like USPEX depend on it.

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🚀 Activate the Environment

mamba activate /bmd/<youraccountname>/envs/my_env

You'll now see the environment name in your terminal prompt. 🟢

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📦 Install Required Packages

Inside the environment, install these useful Python modules:

mamba install spglib
mamba install ase
mamba install numpy
mamba install scipy

Each module plays a role in atomic simulations and numerical operations.

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📴 Deactivate the Environment

When you're done:

mamba deactivate

🔁 You can reactivate the same environment anytime using the mamba activate command again.

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🎉 All Set!

You now have working Python virtual environments on both your Mac 🍏 and the POWER cluster ⚙️. Enjoy clean and reproducible scientific computing!

➡️ Move on to Tutorial 11 for the next step in your journey! 🚀