sigmoid

gaiaunlimited.selectionfunctions.sigmoid(G, G0, invslope, shape)

Generalized sigmoid function.

Note: this function is not robust to numerical issues but works within the range of values we feed it.

Parameters:

• G (nd.array) – where to evaluate the function

• G0 (float) – inflection point

• invslope (float) – steepness of the linear part. Shallower for larger values

• shape (float) – if shape=1, model is the classical logistic function, shape converges to zero, then the model is a Gompertz function.

Returns:

evaluation of the model f(G) = 1 - (0.5 * (np.tanh(delta / invslope) + 1)) ** shape