ansaurus

Hey, I am particularly interested in knowing how did you wrote half_brace method. Is the math you do is a common standard stuff? Can you help pointing me out some resources to learn this?

@Vadi - I added a link to sigmoid functions in the first line of the answer. The half_brace function is the sum of two sigmoidals, and I just thought it was easier to do the sum than break this into four parts. Sigmoidals themselves are fairly common, but this depends on your perspective. In physics, for example (but in topics more advanced than basic undergrad), these appear directly as the Fermi-Dirac distribution function.