文摘
We present original average-case results on the performance of the Ford–Fulkerson maxflow algorithm on grid graphs (sparse) and random geometric graphs (dense). The analysis technique combines experiments with probability generating functions, stochastic context free grammars and an application of the maximum likelihood principle enabling us to make statements about the performance, where a purely theoretical approach has little chance of success. The methods lends itself to automation allowing us to study more variations of the Ford–Fulkerson maxflow algorithm with different graph search strategies and several elementary operations. A simple depth-first search enhanced with random iterators provides the best performance on grid graphs. For random geometric graphs a simple priority-first search with a maximum-capacity heuristic provides the best performance. Notable is the observation that randomization improves the performance even when the inputs are created from a random process.