Multi-physics simulations using a hierarchical interchangeable software
  interface
  We introduce a general-purpose framework for interconnecting scientific
simulation programs using a homogeneous, unified software interface. Our
framework is intrinsically parallel, and conveniently separates all components
in memory. It performs unit conversion between different modules automatically
and defines common data structures to communicate across different codes. We
use the framework to simulate embedded star clusters. For this purpose we
couple solvers for gravitational dynamics, stellar evolution and hydrodynamics
to self consistently resolve the dynamical evolution simultaneousy with the
internal nuclear evolution of the stars and the hydrodynamic response of the
gas. We find, in contrast to earlier studies, that the survival of a young star
cluster depends only weakly on the efficiency of star formation. The main
reason for this weak dependency is the asymmetric expulsion of the embedding
gas from the cluster.
