Calculate damage reduction

Hi, im writing a program to help balance maps but well got a question here.

How does the formula look that gets the % damage reduction from the defence in wc3?

tnx alot.

Taken directly from my armor detection system. Formula from blizzard official site tweaked a little into programming.

Positive Armor: damage*(1-(((armor)*0.06)/(1+0.06*(armor))))
Negative Armor: damage*(2-Pow(0.94,(-armor)))

~Daelin

Tnx alot.

It works good but 1 question is the hero damage reduction calculated in some other way?

normal unit with -2 armor = -11%
hero with -2 armor = -6% (in wc3 atleast)