MutatePerturb.performOperation calculation is not correct

[konical]

In org.encog.ml.genetic.mutate.MutatePerturb.performOperation():

As written this line will not work for small values.
value += (perturbAmount - (rnd.nextDouble() * perturbAmount * 2));

It should be changed to:
value += value * (perturbAmount - (rnd.nextDouble() * perturbAmount * 2));

Examples:
using perturbAmount = 0.2
and random perturbation = ( (perturbAmount - (rnd.nextDouble() * perturbAmount * 2)) )
= -0.1424

using encog calculation -
value = 15, perturbation % = -0.842%, new value = 14.87
value = 0.001, perturbation % = -8771%, new value = -0.086713711

VALUE FOR SMALL NUMBER IS PERTURBED BY ~9000% !

using changed code:
value = 15, perturbation % = -14.24%, new value = 12.86
value = 0.001, perturbation % =-14.24%, new value = 0.000857636

Value for small number is perturbed by the requested amount.

[jeffheaton]

Thanks good point. I will add this soon.

[jeffheaton]

Thank you good fix. I have this in the code now.