Dimension in particle swarm optimization algorithm

Question

In particle swarm optimization algorithm, what is the dimension exactly mean. Is it the number of particles (population size) in the search space? or it is the coordinates of each particle?

Answer 1

It is the dimension of your search space. To better understand this check code line:

Update the particle's velocity: v_i,d ← ω v_i,d + φ_p r_p (p_i,d-x_i,d) + φ_g r_g (g_d-x_i,d)

So, velocity of each particle has d components.

EDIT: Look at this excerpt from the article:

It solves a problem by having a population of candidate solutions, here dubbed particles, and moving these particles around in the search-space according to simple mathematical formulae over the particle's position and velocity.

So, dimension of the search-space is the number of components in a particle.