Nested parallel language preprocessor for converting parallel language programs into sequential code

DETAILED DESCRIPTION The invention comprises a parallel language preprocessor for a nested parallel language.
The preprocessor converts programs written in a nested parallel programming language to sequential programming code and calls to a message passing interface for inter-processor communication.
The parallel language supports nested parallel processing on parallel computers through control and data parallel operations.
The language also supports a collection oriented data type with elements that may be distributed among the processors for data parallel operations.
After the preprocessor has processed the parallel language code, a compiler and linker can be used to provide an executable form of the parallel code for a particular parallel machine.
In particular, the compiler compiles the sequential code into machine executable code.
The linker links the compiled code with run-time libraries supporting functions in the parallel language and the message passing interface.
An implementation of the preprocessor is specifically designed for a nested parallel language that is used to implement irregular divide-and-conquer programs.
The language is based on a nested parallel programming model called the team parallel model.
Significant features of the team parallel model include: 1) recursive subdivision of the processors of a parallel machine into asynchronous processor teams to match the runtime behavior of a recursive divide-and-conquer algorithm, where the number of processors in each team are selected based on computational cost of each recursive function call; 2) switching to efficient serial code (either user supplied or converted from the parallel code by the preprocessor) when the subdivision reaches a single processor; 3) a lazy collection oriented data type that supports data parallel operations within processor teams; and 4) dynamic load balancing of the processing workload among processors.
The preprocessor supports control parallelism by generating code for a split function in the nested parallel language