Feb. 5, 2015
9:35 p.m.
On 04.02.2015 11:45, Daπid wrote:
There are several definitions. Abramowitz and Stegun (http://people.math.sfu.ca/~cbm/aands/page_1020.htm) assign the value 0.5 at x=0.
The NIST handbook uses the value 0 at x=0. Perhaps a Heaviside with an optional argument that defines the value at x=0 would be good. I'd love to see that in NumPy.
Actually, Heaviside function is better seen as a distribution instead of a function, and then there is no problem with the value at 0, as long as it is finite.
Understanding a distribution as the limit of a sequence of functions, the value at x=0 then depended on the choice of function in the sequence, I guess. Using something symmetrical such a Gaussian or a centred box then makes the value of 0.5 plausible. Alex