Progress Report

Our project work started in September 1997. The first three months of the project were dedicated to the design of the interpretation mechanism: the lazy narrowing calculus developed by Prof. Ida was extended towards parallelism and constraint solving for which it was corresponingly equipped it with a type system. In September and October, Prof. Buchberger and Mircea Marin from RISC-Linz spent six weeks with the group of Prof. Ida at the University of Tsukuba to elaborate the details in cooperation.

The next tree months of the project (till the end of February 1998) were dedicated to specifying the extended calculus and to implementing the extensions in the functional logic language interpreter.

The resulting language, calculus, and system are documented in detail in Appendix . The system source code, documentation, and electronic tutorial are part of the package distribution.

The implementation work included the development of an interface to external constraint solvers and the introduction of the following processes running external to the interpreter (see Figure ):

• the prototype of a scheduler for distributing the constraints generated by the interpreter to different constraint solving engines;
• a linear constraint solver as a sample for the integration of external solvers with the interpreter.

At that time, the scheduler and the sample solver were implemented as separate Mathematica processes communicating via the MathLink protocol (but still running within one machine in a pseudo-parallel fashion). The scheduler was asynchronously collecting systems of constraints generated during the execution of the interpreter and forwarding them to the constraint solvers. The simplified solutions were collected and transferred back to the interpreter.

From March to September 1998, the following major changes were made to the system:

• Constraint Solvers: constraint solvers for solving linear, polynomial, and differential equations were added to the system. The scheduler classifies the constraints and partitions them into appropriate sets that it forwards to corresponding solvers.
• Parallelization: both the CFLP program and the CFLP goal may contain explicit parallelization annotations,
• the interpreter and scheduler support the concurrent investigation OR- and AND- parallel annotations.
• Process Distribution: constraint solvers may run on different machines in a network environment.
• Calculus Extensions: the underlying calculus of the interpreter was extended with inference rules to cope higher-order functions and with parallelization annotations.

The period from October 1998 to January 1999 was dedicated to system brushup. This work included:

• the documentation of all the source code and of the system itself,
• the development of an "electronic tutorial" that describes the various aspects of the system in terms of application examples that are embedded in Mathematica notebooks.