If goto's are harmful... In his influential letter "Go to statement considered harmful" , Edsger Dijkstra asserts that goto's make a program difficult to understand. He argues that arbitrary changes of the program control point are difficult to follow in conjunction with dynamic changes to the state of the program data. The abstract control structures of… (More)
What efforts are needed to produce a parallel system (computer architecture and interconnection network) for fast algebraic manipulation? This paper outlines current steps toward such a system, including work in related areas of parallel symbolic processing languages and general- and special-purpose multiprocessor systems.
Side-effects are forbidden in applicative languages like Prolog , FP , pure Lisp , and SISAL . Algorithms can often be reformulated applicatively with no loss of efficiency. It is not known whether this is always the case. Here are seven problems which have been resistant to efficient reformulation. The reader is invited to produce an efficient… (More)
<bold>Prolog has become a subject of much discussion of late. It has been suggested as the logical language for programming expert systems. A parallel variant is said to be the language of the Japanese 5th Generation Project. In this paper the standard Prolog language is defined and shown to be a restriction of Logic Programming. Several alternative… (More)
We outline recent results relating to the use of parallelism for solving problems in algebraic manipulation. Practical issues are discussed.
The performance ratio between two systems tends to vary across different benchmarks. Here we study this variation as a "signature" or "fingerprint" of the systems under consideration. This "fingerprint" can be used to guess the performance of programs not represented in a benchmark suite, assess the breadth and credibility of the benchmark suite, and infer… (More)
Comparing the speed of computation in algebra systems is a perennial occupation of system designers, algorithm implementors, and, more recently, marketing personnel. At least some people have observed that for many problems, the choice of a system makes much less difference than the approach used to represent the problem. The mapping from mathematics to a… (More)