Cilk-5.1 (Beta 1) Reference Manual

This document describes Cilk-5.1, a language for multithreaded parallel programming based on ANSI C. Cilk is designed for computations with dynamic, highly asynchronous parallelism, which can be difficult to write in data-parallel or messagepassing style. Divide-and-conquer algorithms and tree search are examples of computations that are particularly well suited to Cilk. (For example, our group has developed three world-class chess programs, ?Tech [20], ?Socrates [18], and Cilkchess.) Besides search, we have experimented with numerical algorithms such as matrix factorization [5] and N-body simulations, and we are working on other types of applications. Unlike many other multithreaded programming systems, Cilk is algorithmic, in that the runtime system employs a scheduler that allows the performance of programs to be estimated accurately [6] based on abstract complexity measures. 1.1 What is included in Cilk-5.1