pyphi.substrate_generator.mechanisms.sigmoid

pyphi.substrate_generator.mechanisms.sigmoid(element, weights, state, *, floor=0.0, ceiling=1.0, determinism=5.0, threshold=0.0, ising=True, inputs=None, **kwargs)

Logistic activation of the weighted input.

The probability that the unit is ON at the next step is σ(determinism · (Σ_i w_i s_i − threshold)), where the inputs s_i are the unit’s current input states (mapped to ±1 when ising is True) and w_i their weights. determinism is the slope k of the logistic unit in Albantakis et al. (2023, Eq. 60) and Marshall et al. (2023, Eq. 2): larger values make the unit more deterministic. floor and ceiling clip the output.