Fig. 4.

Objective function (F(m)) and particle positions at the end of PSO using ${\alpha }_1^{max}={\alpha }_2^{max}=2.75$ and ${\alpha }_1^{min}={\alpha }_2^{min}=0.5$: a calculated F(m) for the best particle (red dots) and the rest of the swarm (black dots) at each PSO iteration; b calculated F(m) as a function of the particle positions (ρ) in the search space, at the first (gray dots) and final (blue dots) iterations; c plain view of b; d final distribution of F(m) for the swarm at last iteration