Sigmoid shape special function which occurs in probability, statistics and partial differential equations
In mathematics, the error function, often denoted by erf, is a function defined as: erf z = 2 π ∫ 0 z e − t 2 d t. {\displaystyle \operatorname {erf} z={\frac {2}{\sqrt {\pi }}}\int _{0}^{z}e^{-t^{2}}\,\mathrm {d} t.} Wikipedia