Git Version

git clone

Prerequisites for running NRPy+

Quick install from the command line (bash shell)

First set up a virtual environment:

python3 -m venv nrpyvirtualenv
source nrpyvirtualenv/bin/activate
pip install -U sympy jupyter matplotlib scipy

Next navigate to the desired parent directory of NRPy+. Then from this directory

git clone
cd nrpytutorial
jupyter notebook

Your web browser should open the NRPy+ folder; click on NRPyPlus_Tutorial.ipynb to get started!

Windows installation instructions

Slides courtesy Brandon Clark

Browse NRPy+ source code online:

No Download Option (Collide black holes from your browser!)

If you want to perform black hole collision simulations right now, no download or installation is necessary! You can run your own black hole collision simulations from within your web browser! Here's how:

  1. Open the Interactive NRPy+ Tutorial (it might take a minute to load), hosted by the mybinder cloud.
  2. Click the "Colliding Black Holes!" module near the bottom (in purple).
  3. Click the "Fast-forward" button at the top, and then "Restart and Run All Cells". NRPy+ will first generate Einstein's equations of general relativity in the form of a highly optimized C code. Then the C code will be compiled into an executable and run on the cloud server. Finally, matplotlib is used within the notebook to visualize the output. The whole process takes about 10 minutes, but the movie near the bottom visualizes what just happened (reproducing what is on the homepage)
  4. If you want to fiddle with the black hole parameters, you can for example change the masses of the black holes by editing the line of code
    const REAL BH1_mass = 0.5,BH2_mass = 0.5;
    to whatever you like, and then returning to Step 3 above. It is most useful if the black holes' masses add up to 1. If you are interested in more details, they are all documented in previous NRPy+ tutorial modules.

While the above provides a playground for black hole simulations run in the cloud, the BlackHoles@Home BOINC client (which will enable you to benefit gravitational wave astronomy with your spare CPU cycles) is under development. Please sign up for the newsletter to stay apprised of the latest progress. We'll need your help when the time comes!

Ancient software:

Old (SENR/NRPy+) software repository.

All codes are licensed under the 2-clause BSD license unless otherwise specified.

Email Z. Etienne if you are interested in joining our development effort!