Origin Version (Select Help-->About Origin): 7.0 Operating System: Windows XP Hi, I want to fit experimental datasets but not using a function but other experimental data (my references). Something like y=A.f(x)+B.g(x), where A and B would be the fitting parameters and f(x) and g(x) the 2 references datasets. I have look through the manual of Origin and this forum and I didn't find anything approaching. So if anybody could help me with a solution or at least a way to put in a fitting script not a function but a dataset I would be very thankful.