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Python package for modeling chemical kinetics with diffusion and drift.

Project description


Build status PyPI version Python version DOI (digital object identifier) for latest release on Zenodo License airspeedvelocity coverage chemreac logotype

chremreac is an open source library which aims to collect tools and utilities for modeling of chemical kinetics problems. It is primarily designed to be useful in the context of aqueous phase with external radiation fields (including advection/diffusion processes).

The (heavy) numerical processing is done in rountines written in C++ which have been wrapped in a Python interface using Cython.



The easiest way to install chemreac (on linux) is to use conda:

$ conda install -c chemreac chemreac pytest

and you’re done! To check if chemreac is installed correctly you may run:

$ pytest --pyargs chemreac

which should run the test suite (all tests should pass or xfail). If you are using a special platform with non-standard math libraries you may need to compile your own pacakges. The “recipes” for the conda packages are kept here.

If you are not using the conda package manager you can still install chemreac from source. You will find the instructions for doing so below.

Building from source

Below you will find instructions for installation by building chemreac from source. You may also look in scripts/ folder for automated install scripts used on the continuous integration servers.


Version numbers of dependencies indicate what has been tested:

  • C++ compiler with C++11 support (e.g. GCC >= 4.8)

  • LAPACK (provided by e.g. OpenBLAS)

  • Sundials 2.6.2

  • Python (2.7 or >=3.4)

In addition to the standard library provided by Python, a number of python packages are required (see, they are found on PyPI and are automatically installed when using pip.

For rendering the documentation you also need:

to run all the tests you also need these tools:

  • valgrind

  • graphviz

  • dot2tex

  • pdflatex

Building and installing

Once non-python prerequisites are in installed, you may procede e.g. as:

$ git clone
$ cd chemreac
$ pip install --user -e .[all]
$ ./scripts/

the above procedure works on Ubuntu 14.04 for example.

To specify an alternative LAPACK lib, set the environment variable LLAPACK, e.g.:

$ LLAPACK=openblas python build_ext --inplace

The following environment variables are also supported by (defaults to “0”, enable by setting them to “1”):

Environament variable





Enable parallell evaluation of rhs and jac.



Use unblocked version of dgetrf instead of LAPACK



Evaluate LU decomposition of blocks in parallel



For debugging purposes only



For debugging purposes only

Enabling the first three is known to provide significant speed up for some scenarios (performance is system dependent, hence recommendations are not possible to give without benchmarking).


If you have py.test installed you may run the test suite on the installed package:

$ py.test --pyargs chemreac

All tests should pass (or xfail). If they do not, please file an issue.


Both the correctness (continuous integration) and the performance (benchmarks) of the code base is monitored continuously.

Continuous integration

In order to minimize the risk of (re)introducing bugs into the code base, it is continuously built on a CI server:

Build status

Performace tracking

Benchmarks for tracking the performance of the library are kept at


The source code is Open Source and is released under the very permissive “simplified (2-clause) BSD license”. See LICENSE.txt for further details. Contributors are welcome to suggest improvements at


Björn Dahlgren, contact:
  • gmail address: bjodah

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