Extend HOOMD-blue with a component implemented in C++ for performance-critical tasks, such as pair potential evaluation. A component provides a number of related functionalities. For example, the :py:mod:`hoomd.hpmc` component enables hard particle Monte Carlo methods with HOOMD-blue.
Components can be compiled and installed as built-in components or as
external components. The build process compiles HOOMD-blue and all built-in
components together, requiring one cmake and make. External components
compile and link against a HOOMD-blue installation with a separate invocation of
cmake and make install. A properly configured component may be compiled
either way. When the end user is compiling HOOMD-blue and components from
source, built-in components compile and install everything at once which
minimizes chances for errors (e.g. building HOOMD-blue against python 3.6, but
the component against python 3.7). External components provide more flexibility
for packaging purposes.
The HOOMD-Blue source provides an example component template in the
example_plugin subdirectory. example_plugin demonstrates how to add a
new update command with both CPU and GPU implementations. Use this as a
template when developing your component.
You can fork HOOMD-blue and add your component directly, or you can create a
separate source repository for your component. Create a symbolic link to the
component in the hoomd source directory to compile it as a built-in
component:
$ cd /path/to/hoomd-blue/hoomd $ ln -s /path/to/your_component/your_component your_component $ cd ../build $ make
Built-in components may be used directly from the build directory or
installed.
To compile an external component, you must first install HOOMD-blue. Then,
configure your component with cmake and make install it into the hoomd
python library. Point CMAKE_PREFIX_PATH at your virtual environment (if
needed) so that cmake can find HOOMD:
$ cd /path/to/your_component $ mkdir build && cd build $ CMAKE_PREFIX_PATH=/path/to/virtual/environment cmake .. $ make install
The component build environment, including the compiler, CUDA, MPI, python, and other libraries, must match exactly with those used to build HOOMD-blue.
External components must be installed before use.