ihnorton / pyjulia

python interface to julia

PyJulia

Experimenting with developing a better interface to julia that works with Python 2 & 3.

to run the tests, execute from the toplevel directory

python -m unittest discover

Note You need to explicitly add julia to your PATH, an alias will not work.

pyjulia is tested against Python versions 2.7 and 3.5. Older versions of Python (than 2.7) are not supported.

Installation

You will need to install PyCall in your existing Julia installation

Pkg.add("PyCall")

Your python installation must be able to call Julia. If your installer does not add the Julia binary directory to your PATH, you will have to add it.

Then finally you have to install pyjulia. You may clone it directly to your home directory.

git clone https://github.com/JuliaPy/pyjulia

then inside the pyjulia directory you need to run the python setup file

sudo python setup.py install

pyjulia is known to work with PyCall.jl ≥ v0.7.2.

If you run into problems using pyjulia, first check the version of PyCall.jl you have installed by running Pkg.installed("PyCall").

Usage

To call Julia functions from python, first import the library

import julia

then create a Julia object that makes a bridge to the Julia interpreter (assuming that julia is in your PATH)

j = julia.Julia()

You can then call Julia functions from python, e.g.

j.sind(90)

How it works

PyJulia loads the libjulia library and executes the statements therein. To convert the variables, the PyCall package is used.

Limitations

Not all valid Julia identifiers are valid Python identifiers. Unicode identifiers are invalid in Python 2.7 and so pyjulia cannot call or access Julia methods/variables with names that are not ASCII only. Additionally, it is a common idiom in Julia to append a ! character to methods which mutate their arguments. These method names are invalid Python identifers. pyjulia renames these methods by subsituting ! with _b. For example, the Julia method sum! can be called in pyjulia using sum_b(...).