By John C. Platt (1999) MIT

Main

1. Modified (enhanced) sigmoid function
   $$p_i = \frac{1}{1 + \exp(Ax + b)}$$
2. Scaled cost function
   $$J = -\frac{1}{m}\sum_{i}{(t_i\log{p_i} + (1 - t_i)\log(1 - p_i))}$$
   where $t_i\in\{0, 1\}$ is the class label.