Swarm Intelligence Algorithms

126 Dynamic Virtual Bats Algorithm

If the current solution is not the best solution ever found then the bat

becomes the explorer bat, changes its direction randomly, increases the wave-

length, and decreases the frequency expanding the search scope (step 18, 19,

and 20). These actions help the bat keep exploring the search space without

getting trapped in a local optima and provides a random walk.

If the bat is already on the best found position (x

gbest

) or a better one,

the bat will become the exploiter bat. The wavelength will be minimized

(λ

t+1

i

) = (λ

min

) , the frequency will be maximized (f req

t+1

i

) = (freq

max

),

and the search direction will be