  BondGraphTools is a Python library for scripted modelling of complex
multi-physics systems. In contrast to existing modelling solutions,
BondGraphTools is based upon the well established bond graph methodology,
provides a programming interface for symbolic model composition, and is
intended to be used in conjunction with the existing scientific Python
toolchain. Here we discuss the design, implementation and use of
BondGraphTools, demonstrate how it can be used to accelerate systems modelling
with an example from optomechanics, and comment on current and future
applications in cross-domain modelling, particularly in systems biology.
