Re: st: nonlinear regression with restrictions

[Steven Samuels <samplerx@earthlink.net>]

nl (y = {a1=?} + {a2=?}*x + (x{b=?})*{a3=0}*(x-{b})^2)

Where you should plot the data and substitute initial values for a1,  
a2, and b.  See the "nl" documentationn for options and robust  
standard errors.


> Michael Stobernack wrote:
> > Dear all,
> >
> > I would like to run the following nonlinear regression:
> >
> > Y = a1 + a2 * X +a3 * (1 - dk) * (b**2 - 2 * b * x + x**2) + u
> >
> > with dk = 1 if x <= b  and dk = 0 if x > b
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