Hi, probably a fairly basic question, hopefully someone will be able to help. I have the following equation which I want to fit to a set of data:

$\displaystyle y=a-b e^{-c(x-d)^2}$

If my data points are $\displaystyle (x_1,y_1), (x_2,y_2), ...$ , what would be the best way to go about solving for a,b,c,d?