| Temporary announcement |
|---|
| 1) We will soon add a new branch in this repository which is a rewrite of i-PI master in Python3. |
| 2) New developments should start being based in that branch and we will make sure any updates to master made up to October 31st, 2019, in python2 are translated into that branch in python3. |
| 3) Any pull requests based on the python2 implementation that are not accepted before October 31st will not be accepted afterwards. We will not accept any further pull requests that are not based on the new python3 rewrite. If you have ongoing developments, think about what you want to merge before and what you can transfer to the python3 version. |
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| ==== |
| i-PI: a Universal Force Engine |
A Python interface for ab initio path integral molecular dynamics simulations. i-PI is composed of a Python server (i-pi itself, that does not need to be compiled but only requires a relatively recent version of Python and Numpy) that propagates the (path integral) dynamics of the nuclei, and of an external code that acts as a client and computes the electronic energy and forces.
This is typically a patched version of an electronic structure code, but a simple self-contained Fortran driver that implements Lennard-Jones and Silvera-Goldman potentials is included for test purposes.
To use i-PI with already existing drivers, install using Pip:
$ pip install git+https://github.com/i-pi/i-pi.gitTo develop i-PI or test it with the self-contained driver, follow these instructions. It is assumed that i-PI will be run from a Linux environment, with a recent version of Python, Numpy and gfortran, and that the terminal is initially in the i-pi package directory (the directory containing this file).
Source the environment settings file env.sh as $ source env.sh or $ .
env.sh. It is useful to put this in your .bashrc or other settings file if you always want to have i-PI available.
$ cd drivers
$ make
$ cd ..This will first start the wrapper in the background, redirecting the output to a log file, and then run a couple of instances of the driver code. The progress of the wrapper is followed by monitoring the log file with the tail Linux command.
Optionally, you can make a copy of the directory with the example somewhere else if you want to keep the i-PI directory clean.
$ cd examples/tutorial/tutorial-1/
$ i-pi tutorial-1.xml > log &
$ i-pi-driver -h localhost -p 31415 -m sg -o 15 &
$ i-pi-driver -h localhost -p 31415 -m sg -o 15 &
$ tail -f logThe monitoring can be interrupted with CTRL+C when the run has finished (5000 steps).
The automatic test suite can be run with the Python package pytest from the root directory of the i-PI project.
$ pytest -vi-PI code should be compliant to a minimal subset of PEP-8 recommendations. Before proceeding to a pull request, or to the merging of a large commit, you can use the following script to automatically prettify the code
` i-pi-pepper -p $IPI_ROOT`