An implementation of GJ has been written in GJ, and is freely available on the web.

A gzipped MPEG movie of Adaptive Mesh Refinement modelling ripples in a viscous fluid mentioned in the text.

Sather extends the notion of an iterator in a powerful new way. We argue that iteration abstractions belong in class interfaces on an equal footing with routines. Sather iterators were derived from CLU iterators but are much more flexible and better suited for object-oriented programming. We retain the property that iterators are structured, i.e. strictly bound to a controlling structured statement. We motivate and describe the construct along with several simple examples. We compare it with iteration based on CLU iterators, cursors, riders, streams, series, generators, coroutines, blocks, closures, and lambda expressions. Finally, we describe experiences with iterators in the Sather compiler and libraries.

This report addresses typing problems that arise when modelling simple mathematical entities in strongly typed languages such as Sather, which are eliminated by a proper distinction between mutable and immutable abstractions. We discuss the reasons why our intuition leads us astray, and provide a solution using statically type-safe specialization through constrained overloading. We also discuss the type relationships between mutable and immutable classes and the notion of freezing objects.

The integration of zones into the Sather language is described, including an implementation of memory management customized to parameters of the memory system.

Method overloading is a form of statically resolved multi-methods which may be used to express specialization in a type hierarchy. The design of the overloading rule in Sather is constrained by the presence of multiple subtyping and the ability to add supertyping edges to the type graph after the fact. We describe the design of overloading rules which permit method specialization while allowing separate type checking, i.e., existing code cannot be broken by the after the fact addition of supertyping edges.

A major effort then began to redesign the language to correct shortcomings in Sather 0 and to make Sather suitable for general-purpose, large scale programming. In part because each compiler group was building a compiler for a moving design target, the two parallel efforts resulted in two dialects, Sather 1 and Sather K. This report analyzes the essential causes of the differences, which result from differences in each group's goals.

One of the most interesting lessons of the last year has been a major revision of how thread termination is handled. There was a "gate.clear" command that terminated all threads attached to a gate, regardless of their state. We eventually convinced ourselves that there is no way to do this that guarantees correct semantics. Meanwhile, we had been discussing whether it was worth adding disjunctive locks to the language. It turns out that disjunctive locks cleanly handle all the cases in which we were using asynchronous thread termination.

This 1.1 specification significantly polishes and improves the 1.0 language specification with an introduction, index, and examples. New constructs include `out' arguments, less restrictive overloading, and improved external language interfaces.

Sather is an object-oriented language first introduced in 1991. Since then, considerable practical experience has been obtained with the language by the hundreds of users making up the Sather community. Sather offers many safety and convenience features to help programmers avoid common errors and reuse code. Some of these were discussed in a previous Computers in Physics article; they include strong typing, garbage collection, object-oriented dispatch, multiple inheritance and parameterized classes. Here we mention other advantages that have come to maturity since then, including iteration abstraction and parallel and distributed language extensions.

This document is a concise specification of Sather 1.0. Sather is an object oriented language designed to be simple, efficient, safe, flexible and non-proprietary. Sather has parameterized classes, object-oriented dispatch, statically-checked strong (contravariant) typing, separate implementation and type inheritance, multiple inheritance, garbage collection, iteration abstraction, higher-order routines and iters, exception handling, assertions, preconditions, postconditions, and class invariants. The ICSI compiler supported this 1.0 specification from 1994 through much of 1995.

This document describes pSather 1.0, the parallel and distributed extension to Sather 1.0 (see ICSI tech report TR-95-057). pSather adds support for threads, synchronization, communication, and placement of objects and threads. The ICSI compiler supported this 1.0 specification through much of 1995.

The Connectionist Network Supercomputer, or CNS-1, is a multi-year effort to incorporate recent advances in VLSI design and application-specific computer architecture for the realization of a massively parallel machine. Application targets for the CNS-1 include connectionist networks in the areas of speech recognition, language modeling, vision, and hardware simulation for VLSI. This technical report presents the background and motivation for high-level design decisions, along with descriptions of several hardware and software elements. The document represents a "snapshot" of the design, which is expected to be operational in 1995.

Source code mentioned in the text.

The game of go is an ideal problem domain for exploring machine learning; it is easy to define and there exist many skilled human experts, yet existing programs have failed to emulate their level of play to date. Existing techniques used by computers to play go are surveyed. An error function is defined which is used by several classifications techniques and genetic algorithms to automatically derive patterns representative of good moves.