Coupling Multicomponent Models with MPH on Distributed Memory Computer Architectures
The international journal of high performance computing applications
A growing trend in developing large and complex applications on today's Teraflop scale computers is to integrate stand-alone and/or semi-independent program components into a comprehensive simulation package. One example is the Community Climate System Model which consists of atmosphere, ocean, land-surface and sea-ice components. Each component is semi-independent and has been developed at a different institution. We study how this multi-component, multi-executable application can run
... ly on distributed memory architectures. For the first time, we clearly identify five effective execution modes and develop the MPH library to support application development utilizing these modes. MPH performs component-name registration, resource allocation and initial component handshaking in a flexible way. Keywords: multi-component, multi-executable, component integration, distributed memory architecture, climate modeling, CCSM, PCM. version 2 was developed for the multi-component single-executable mode (see Sections 2.2 and 4.1) for the PCM model. MPH version 3 was developed for the multi-component multi-executable mode (see Sections 2.4 and 4.3) to provide a unified user interface for MPH1 and MPH2. The multi-instance-executable and the command line argument passing (discussed in Section 4.4) are implemented in MPH version 4 to support climate ensemble simulations to ascertain the uncertainty in climate predictions. Currently, all MPH functionalities work on the IBM SP, SGI Origin, HP AlphaServer SC, and Linux clusters. Source codes and instructions on how to compile and run on all these platforms are publicly available on our MPH web site  . MPH has been adopted in CCSM development  . CCSM is the U.S. flagship coupled climate model system most widely used in long-term climate system modeling in the U.S. MPH has been adopted in NCAR's Weather Research and Forecast (WRF) model . MPH is also used in the Colorado State University's geodesic grid coupled model. A Model Coupling Toolkit  for communication between different component models uses MPH. Edinburgh Parallel Computing Centre (EPCC) at the University of Edinburgh uses MPH for ensemble simulations.