Standard logistic sigmoid function (k=1, x0=0, L=1)


A logistic function or logistic curve is a common “S” shape (sigmoid curve). Data that follows an increasing logistic curve usually describes constrained growth or a cumulative quantity. For small values of the independent variable, the increasing logistic function behaves very much like an (increasing) exponential function. A sigmoid function is a bounded differentiable real function that is defined for all real input values and has a positive derivative at each point.

Related formulas


Fxlogistic function (dimensionless)
xVariable (in the range of real numbers from −∞ to +∞) (dimensionless)