inverseAbs

[ilhame]

Hi,

I want to ask you about the inverseAbs function. In http://sharpneat.sourceforge.net/network_optimization.html page, it is equal to y = x / (1 + abs(x)). But in InverseAbsoluteSigmoid.cs program, it equals to y = 0.5 + (x / (2*(0.2+abs(x)))). Which one should I take? and did it return a value between 0 and 1?

Thank you

[Colin Green]

Hi,

If you plot the two functions you will see that they are both S
shaped, but that y = x / (1 + abs(x)) has a range of about -1 to 1 on
the y-axis, whereas the 2nd function has a range of about [0,1], which
is the range you will normally see for activation functions. So my
general advice would be to go for the second function (the one in the
code) unless you are working an a problem were you know that you want
an activation function with range [-1,1] (known as a bipolar
function).

Colin