Non negative linear regression with root?

How can I do a non negative linear regression with root?
I need to find positive parameters a_i for the model

 y = a_0 + a_1 * x_1 + a_2 * x_2 + ....

For the general solution I can use TLinearFitter, but how can I add a constraint of only positive parameters?

Hi,

We do not have a constrained fitter in ROOT. You might try to use something in R and use it via the ROOT-R interface
root.cern.ch/doc/master/md_bind … Guide.html

Best Regards

Lorenzo