Pthomas: An adaptive information retrieval system on the connection machine

This paper reports the state of development of PThomas, a network based document retrieval system implemented on a massively parallel fine-grained computer, the Connection Machine. The program is written in C*, an enhancement of the C programming language which exploits the parallelism of the Connection Machine. The system is based on Oddy’s original Thomas program, which was highly parallel in concept, and makes use of the Connection Machine’s single instruction multiple data (SIMD) processing capabilities. After an introduction to systems like Thomas, and their relationship to spreading activation and neural network models, the current state of PThomas is described, including details about the network representation and the parallel operations that are executed during a typical PThomas session.