2. Installation

2.1. Dependencies

Like most Python programs, MEASURE relies on a number of Python packages for certain functionality. The following lists the required Python packages that are not part of the Python standard library:

• NumPy. Provides efficient array and matrix operations.
• SciPy. Provides efficient linear algebra functions and special functions.
• Quantities. Provides unit conversions of physical quantities.
• Cython. Compiles certain computationally-intensive modules to C code, often resulting in a dramatic speed increase, mostly due to static typing of variables.

The following lists the optional Python packages that are not part of the Python standard library:

• Cairo. Provides 2D drawing support, used for automatic drawing of potential energy surfaces.

Finally, MEASURE also depends on the Green group’s base library for Python projects, named ChemPy.

2.2. Installing MEASURE

Once you have obtained the required dependencies, MEASURE can be installed by executing the following command from within the root package directory:

$ python setup.py install

This will move all of the necessary files to the appropriate Python installation location on disk. If Cython is installed, this will also compile the appropriate modules prior to installation.

You can also use MEASURE without installing if you prefer. This is done by appending the full path to the package’s root directory to your PYTHONPATH environment variable. To compile the Cython modules in this case, use the command

$ python setup.py build_ext --inplace

You can remove the temporary build files - but not the compiled libraries! - via the command

$ python setup.py clean

If you have the make build automation tool installed, you can also use the provided Makefile, via

$ make install

to install,

$ make

to build in-place, or

$ make clean

to remove all temporary build files and compiled files.