I have to fit a non linear model to my data and I am trying to use NonlinearModelFit
.
The problem is that I have systematic errors, so the weights
options is not a simple vector but a matrix.
To be clear: my chi squared is written as:
(diff)T*(weight)^(-1)*(diff)
Where diff
is the difference between my model and the data (T means trasposed).
Does anyone have any idea?
I use Mathematica 8.