Parallelized Models Development Approach (PMDA) And Its Application

The numerical simulation for complicated problems and advances of computers in recent years made in multi-core and network demand changing traditional developing approach of numerical models that resolve all problems in one single program with serial computing. Based on multi-processing and network, a parallelized models development approach (PMDA) is proposed, specially being applied for the time dependent models, to change the simulation of complicated processes into parallel computing of many simple models and exchanging data with each other. The main work and achievements in the thesis are as follows:1. The analysis of the demands of models and technical trend of computer result in the conclusion that PMDA is one of key issue to simulate complex problems evolved with different dimensions, scales and multi-physic processes under the multi-core hardware environment. Then, the aim, task and technique routing of PMDA are presented.2. A way of PMDA aiming at time dependent models is proposed to simulate a complicated process easily by assembling models with different dimensions and characters from each other work together as one model and parallel computing in time step level. Under the framework architecture with a central controller, data can be indirectly exchanged between involved models only by inserting a probe function into each model source code at main time loop. Network and TCP/IP protocol is basic technique to transmit data between models and central controller. Exchanged data is represented in the form of"quantity-location-time". Assembling information is organized in four level-model, quantity, grid and data transition. A weight and an adder matrix are introduced to change the data from source model into that the target model need. A schedule mode named as"by time, with rhythm", the explicit and half implicit time coupling approach, and spatial and temporal polishing method by average are presented to coordinate the parallel running of models.3. The PMDA is implemented by mixed programming of C++ and Fortran. The correlated software including the middleware and code template used to change a model to model-component, assembling and control platform and client to manage remote models are developed to decrease the difficulty of developing parallel assembling model so that PMAD may be used easily and admitted by extensive researchers.4. Some kinks of assembling cases are studied using PMDA and software built in this paper. What happened when models are assembled is brought to light and preliminarily analyzed. Simple examples indicate extensive application of PMDA in data exchanging and logical controlling between models. The study of Three Gorge Reservoir (TGR) compensative operation according flood at Chenglingji makes clear that TGR has an important effect on the flood from Mid Reach of Yangtze River.5. What should be paid attention to when developing sub-models and PMDA system aspect is listed in the standard of PMDA (outline). It can be the base for the formal standard set in the future.In total, PMDA can be used to make the best of the capability of multi-core computer and network and avoid of developing ultra-complex models. More simple, efficient and reasonable simulation route for complicated problems in the multi-core computing environment is explored out by using PMDA.