Can someone explain Sensitivity Analysis to a computer programmer

There are lots of long texts about Sensitivity Analysis but as a programmer I get easily bored or can't understand it.

Can someone briefly explain Sensitivity Analysis to a programmer?

Thanks.

Sensitivity analysis covers a lot of different things. Then, since you are a programmer, let me suppose that you make a call to a function $F(a,b,x)$ which returns to your program the profit $P_0$ of a plant running at operating conditions $a$ and $b$. Now, change your first set point to $(a+\Delta a)$ and $b$ al call $F(a+\Delta a,b,x)$ to get $P_1$. This gives you the sensitivity of the profit to the first set point value. This looks like derivatives, isn't ?

http://en.wikipedia.org/wiki/Sensitivity_analysis is a good and simple view of it and I just quote the beginning of what they write

Sensitivity analysis is the study of how the uncertainty in the output of a mathematical model or system (numerical or otherwise) can be apportioned to different sources of uncertainty in its inputs.

• Thanks. So what Sensitivity analyse brings to us? Does it bring a mathematically easy solution for finding which condition changes profit more? Or it is just a way to explain the purpose of the analysis? I can use computer to see which condition changes output more, but it will take lots of time. – Ramazan Polat Mar 17 '14 at 13:52