The movement of particles in the ProjPSO search for the D-optimal design for the linear additive mixture model with q = 3 factors.

Each sub-figure displays the ProjPSO-generated mixture design or the global best design ξ^gbest at a particular iteration. After 40 iterations and only 4 seconds of CPU time, ProjPSO converged to the D-optimal design equally supported at the vertices.