α

filter packing density

β          

adjustable parameter

γ          

learning rate

δi           

training data output values

η          

single fiber efficiency

ηANN           

single fiber efficiency estimated by ANN

ηNumeric           

numerical single fiber efficiency

q

polar coordinate dimensionless

ζi         

network output values

σi         

network input values

ip, xip)         

outputs of the network with the same input

ip, dip)         

the p-th pair pre-assigned input/output