Menu
I know that both of them select K randomly, and then choose the best K, as I understand the best K call the others to find the goal, so what is the exact difference between Local beam search and Stochastic beam search ? Please help me and correct to me if I am wrong
770
Stochastic beam search is an alternative to beam search, which, instead of choosing the best k individuals, selects k of the individuals at random; the individuals with a better evaluation are more likely to be chosen. This is done by making the probability of being chosen a function of the evaluation function.
Variants of Beam SearchIn the context of a local search, we call local beam search a specific algorithm that begins selecting β generated states. Then, for each level of the search tree, it always considers β new states among all the possible successors of the current ones until it reaches a goal.
Local Beam Search In this algorithm, it holds k number of states at any given time. At the start, these states are generated randomly. The successors of these k states are computed with the help of objective function. If any of these successors is the maximum value of the objective function, then the algorithm stops.
In fact, the two algorithms are quite different. In a random-restart search, each search process runs independently of the others. In a local beam search, useful information is passed among the parallel search ◀ threads.
Stochastic pretty much means randomized in some way. One of the major issues with beam search is that it tends to get stuck into local optima instead of the global optimum. To avoid that stochastic search gives some(most often small) probability of the solution to choose the step that is not optimal at a given moment. You can think of that as "adding randomness". A bit better approach would be simulated annealing where the chance to take suboptimal choice decreases with time.
Local search on the other hand will always choose the best K neighbours, never allowing to deviate from a local optimum if you happen to hit one.
195
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
