Contrary View: Model Accurately
“Communication is the most expensive aspect of parallel computing, structure the computation so it optimizes use of communication”
Structuring a program to optimize comm embeds properties of a given computer into the source code
Parallel machines are very different ==> source must be changed for each machine
Wisdom: Do not try to be too accurate. Think of @-Comm as a small, but nonnegligible (fixed) cost, leave optimization to compilers