Symbol	Description
$\omega$	Inertia weight for velocity update
c	Acceleration constant
r	Random number in $[0,1]$
$P_o$	Guide particle constructed using OED from $P_b$ and $G_b$
$P_b$	Historical best position of the particle
$G_b$	Global best position found by the swarm
$h_1,h_2$	Probabilities for mutation and crossover operations
$X_i^t$	Position of particle i at iteration t
$V_i^t$	Velocity of particle i at iteration t
$F_1,F_2,F_3$	Functions for mutation, OED, and crossover
$L\left[a\right]\left[b\right]$	Element of orthogonal array at row a, column b
M	Number of experimental particles or rows in the array
D	Number of dimensions (equal to number of connection pairs)
u	${log}_{2}M$, used for orthogonal array construction
$k_{ijq}$	0–1 indicator in orthogonal matrix
$S_{jq}$	Score of level q in dimension j
$CN$	Number of intersections in routing
L	Total length of channels
$T_{\mathrm{total}}$	Total conflict time among connection pairs
$\mathrm{Fitness}\left(X_i\right)$	Fitness value of particle i
$it$	Current iteration number
iterators	Maximum number of iterations
${\omega }_{\mathrm{start}},{\omega }_{\mathrm{end}}$	Start/end values of inertia weight
$h_{\mathrm{start}},h_{\mathrm{end}}$	Start/end values of crossover probability