Installing OpenQuake with Conda

Warning! This is not officially supported!

I use conda extensively to manage Python environments. While I have my frustrations with it, in particular the slow and brittle dependency solver, it services my needs rather well.

However, no one else at GEM uses it, so it's not supported as an environment host for OpenQuake. Nonetheless, here's what I do in general (though this seems to change slightly every year or so, whenever I make a new environment for whatever reason). Note that this involves installing from source (i.e., GitHub), rather than releases, on Linux or MacOS (or with WSL on Windows), though you could do it from the source code from a given point release if you need a specific version. I assume you already have conda installed.

Step 1: Clone (or download) the engine from GitHub and go into the oq-engine/ directory.

git clone git@github.com:gem/oq-engine.git

Step 2: Go to requirements-py3x-yyyy.txt (for the platform and Python version you're using) and comment out the line with certifi (conda will install a newer version that is uniquely compatible with the exact version of Python it installs).

Step 3: Make a new conda environment with the Python version you want.

conda create -n oq python=3.9

Step 4: Activate the new environment.

conda activate oq

Step 5: Install the requirements with pip.

pip install -r requirements-py3x-yyyy.txt

Step 6: (Optional but highly recommended) Install Numba, which is easiest through conda. This will also install a lot of other libraries for numerical computing, e.g. BLAS and MKL. (Note, numba may already be installed by the requirements.txt file)

conda install numba

Step 7: Install the OpenQuake Engine in development mode.

pip install -e .

And that should work!