Abstractions for parallel N-body simulations

Introduces C++ programming abstractions for maintaining load-balanced partitions of irregular and adaptive trees. Such abstractions are useful across a range of applications and MIMD architectures. The use of these abstractions is illustrated for gravitational N-body simulation. The strategy for parallel N-body simulation is based on a technique for implicitly representing a global tree across multiple processors. This substantially reduces the programming complexity and the overhead for distributed memory architectures. The overhead is further reduced by maintaining incremental data structures