Local Search and Stochastic Algorithms

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Local Search Algorithms
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Presentation transcript:

Local Search and Stochastic Algorithms Tutorial

Hill Climbing Describe the way to use Hill Climbing to solve N-Queens Problem.

Beam Search Describe the way to use Beam Search Algorithm to solve TSP Problem. 2-opt (2-swap)

Genetic Algorithms Consider the following fitness function: fitness (bitstring) = number of 1’s in the bitstring where both adjacent bits are 0’s: (010). For example, fitness (“010110100”) = 2; fitness (“100011011”) = 0; and fitness (“010101010”)= 4. (Notice that 1’s in the first or last position in the string are not counted in the fitness function, even if adjacent to a 0.) Assume the design of our genetic algorithm is: (a) Create an initial population containing 4 random 9-bit strings. (b) Discard the 2 least-fit ones. (c) Do a single-point cross-over using the 2 most fit. The 2 children that result and their parents constitute the next generation. (d) Randomly mutate 1 bit in 1 string in the population. (e) Go to step (b).

Genetic Algorithms Start with the initial population below and show what the next two (2) generations might look like. Explain your reasoning. Generation 0 0 1 1 1 1 0 1 1 0 0 1 1 0 0 1 0 1 1 1 0 1 1 0 1 1 1 0 0 0 0 0 1 0 1 0 1 Generation 1 Explanation Generation 2 Explanation

Genetic Algorithms Describe the way to use Genetic Algorithm to solve TSP Problem. 2-opt (2-swap)