IBM 4381-P03型双CPU计算机实现NWP模型的并行计算

本文介绍数值天气预报（NWP）问题，用IBM4381—P03型计算机的两个CPU，实现气象物理模型x-y方向“分解-联合”的自稳定差分格式的并行计算的初步情况:（1）4381-3型的CPU可按通常理解的分开任务方式实现并行计算；（2）MVS大型操作系统控制VS FORTRAN库中的MTF（Multitasking Facility）实行分开任务-并行处理-等待同步，从而实现NWP模型的并行运算，这在我国气象问题计算中还是第一次，今后卫星数据处理的新方案可用4381-3双CPU并行处理，老方案也可逐步变成并行计算；（3）并行加速达到1.3—1.5，尚未达到IBM公司的1.8加速水平，还有潜力可挖。

Implementation of the Parallel Algorithm for the NWP Model with IMB 4381–P03 Dual CPU

This paper presents the parallel algorithm experimental results on numerical weather prediction, which have been carried out by using the dual CPU computer system consisting of three IBM 4381-P03 installed at SMC/SMA, Beijing, According to the x-and y-coordinate directive decomposion (fork)-composion (join), the IBM 4381-P03 dual CPU have executed the calculation of the model difference scheme which is conditionally stable in form but nonconditionally stable in fact. The preliminary experiment results show: (1) IBM 4381-P03 with dual CPU can excite parallel algorithm in a common separate task way. (2) MVS grand operating system controls the Multitasking Facility (MTF) in the VS FORTRAN library to execute the decomposing task—parallel processing—waiting synchronization, to carry out the parallel algorithm. It is the first time to calculate NWP model in parallel way in China. From now on, we may execute step by step the parallel algorithm on the NWP and on the satellite informations processing. (3) In our estimation, a speed-up ratio of the parallel programming for the initial value problem is about 1.3 to 1.5, but not reaches the 1.8 level of the IBM yet. So it is worth to further exploit potentialities of the dual CPU