The class is libLSS/physics/bias/linear_bias.hpp, class is LibLSS::bias::LinearBias.

This class implements the linear bias model. Its corresponding mathematical model is {$$\rho_g = \bar{n}(1 + b \delta_m),$$} with {$\bar{n}$} a normalization constant, {$b$} the linear bias factor, {$\delta_m$} the matter density fluctuation.