Notes. The parameter b_link,0 is the basic linking length, which corresponds to the distance to nearest visible neighbour at redshift zero. The coefficient α_opt allows for proper scaling of the angular linking length, while the coefficient R_opt does the same for the radial linking length (in the redshift space). The coefficient λ_opt provides the optimized dependence on the scaling of the Malmquist bias correction. S_tot is the median value of the group cost function calculated using all mock catalogues and the optimal coefficients.