Hello,
I have a problem. I am using the NLME library to fit a non-linear model. There
is a linear component to the model that has a couple parameter values that can
only be positive (the coefficients are embedded in a sqrt). When I try and
fit the model to data the search algorithm tries to see if a negative value
for one of these parameter values will produce an optimal fit. When it does
so, it crashes because the equation can not have a negative value because its
in a sqrt function.
QUESTION: How do I restrict the optimisation algorithm's parameter space so
it does not search negative values when using GNLM? Are there other Libraries
that Fit Non-linear models and allow for one to control the parameter space the
search algorithm is restricted by?
Any help would be appreciated.
Thanks
Dom
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