Contains class for implementing a linear-boolean update function, defined as follows.

Gi:L0 = Gi:L1(1 - rate) + Li(parents(Gi:L0)/Gi:L1) * Fi(parents(Gi:L0)/Gi:L1) + ei,

where Li is a linear function of the causal parents of a gene i from previous time steps, F is a Boolean function of the causal parents of gene i from previous time steps returning +1 or -1, ei is an error term chosen from N(0, s.d.), and rate is a constant governing how quickly expression levels return to zero.