Space-for-Time Optimization Aspects A Case for Harmless Aspects with around Advice

The space-for-time trade-off is one of the earliest to be discovered in computer science. Taking program complexity into account, we can safely call it “space and elegance”for-time trade-off. Contemporary algorithms text books often tackle the complexity problem by first presenting algorithms in an elegant, but inefficient form, followed by a few paragraphs informally describing optimizations. We used aspects to improve the presentation of several algorithms like Topological Ordering, Dijkstra’s shortest path, Closest Pair, Stable Marriage, etc. Harmlessness is a key safety requirement for optimization aspects. Existing models for harmless aspects disallow general around advice which is indispensable for expressing optimization aspects. We present a model for harmless aspects with around advice. We also present a domain specific model for space-for-time optimization aspects that rules out several situations when the optimization aspect is not improving the runtime efficiency and enables more informative error messages.