A Study on Abstract Machines for Concurrent Rewriting

我们设计了一个并发(并行)重写抽象机--并行TRAM，并行TRAM能够合理地控制并行重写，它是由代数规范语言OBJ2提出的求值策略(E-策略)的扩展，可以合理地控制并行重写。我们还在装有128个处理单元的大规模并行计算机Cray Research T3E上，用广泛使用的消息传递库MOI实现了并行TRAM，称为PTRAM/MPI。通过执行一些基准程序，PTRAM/MPI的顺序重写速度大约是抽象机的50倍。这说明了本研究中所用方法的有效性。我们对PTRAM/MPI进行了更详细的描述。…是一种用于顺序排序条件项(图)重写系统的抽象机，可用于为高级代数规格说明语言如OBJ3和CafeOBJ实现高效的处理器。r TRAM有轨电车更多的改写策略是评估策略(E策略)，它允许人们为每一次运营指定本地策略，以便控制改写。E策略可以模拟懒惰评估的一种变体。并行TRAM是TRAM的一种并行变体，它被设计成在共享内存的多处理器上高效执行，其并行计算模型是共享内存模型。并行有轨电车的重写策略是并行E策略的扩展。并行E策略与条件句相结合，可以合理控制并行重写。PTRAM/MPI是并行TRAM的改进版本，它被设计成在大规模并行计算机或工作站机群上高效地执行，其并行计算模型是消息传递模型。PTRAM/MPI已经在Cray Research T3E上实现，它搭载了128个带有MPI的处理单元。由于MPI，可以很容易地在其他大规模并行计算机或工作站机群上移植或实现PTRAM/MPI。较少

We have designed an abstract machine for concurrent (parallel) rewriting called Parallel TRAM.Parallel TRAM can reasonably control parallel rewriting with the parallel E-strategy that is an extension of the evaluation strategy (the E-strategy) initiated by the algebraic specification language OBJ2. We also have implemented Parallel TRAM on the massively parallel computer Cray Research T3E carrying 128processing elements with the widely used message passing library MOI.The implementation is called PTRAM/MPI.PTRAM/MPI has been found to be about 50 times faster than TRAM the abstract machine for sequential rewriting by executing some benchmark programs with both of them. That shows the usefulness of the approach used in this research.We describe PTRAM/MPI in further detail. TRAM is an abstract machine for order-sorted conditional term (graph) rewriting systems, which may be used to implement efficient processors for advanced algebraic specification languages such as OBJ3 and CafeOBJ.The r … More ewriting strategy of TRAM is the evaluation strategy (the E-strategy) that allows one to specify local strategies for each operation so as to control rewriting. The E-strategy can simulate a variant of lazy evaluation. Parallel TRAM is a parallel variant of TRAM.It has been designed to be efficiently executed on a shared memory multiprocessor, and its parallel computational model is the shared memory model. The rewriting strategy of Parallel TRAM is an extension of the E-strategy called the parallel E-strategy. The parallel E-strategy may control parallel rewriting reasonably by combining with conditionals. PTRAM/MPI is an improved version of Parallel TRAM.It has been designed to be efficiently executed on a massively parallel computer or a workstation cluster, and its parallel computational model is the message passing model. PTRAM/MPI has been implemented on Cray Research T3E carrying 128 processing elements with MPI.Thanks to MPI,it may be easy to port or implement PTRAM/MPI on other massively parallel computers or workstation clusters. Less