NLLS estimation

[Chris]

Hello,

I am quite new to EViews and I desire to estimate a model that includes a hyperbolic tangent with NLLS. Equation is of the form Yt= c1+c2*Xt +tanh((Xt+1-Xt)*(c3*Xt-c4*Pt)). A syntax error appears when implemented. What are the proper steps for estimating such parameters? Should I provide some starting values from a restrictive case? Would another method like maximum likelihood be more appropriate?
Your help will be very much appreciated!

Chris

[trubador]

You can enter the following into the equation editor:

Code: Select all

y= c(1) + c(2)*x + (@exp(2*((x(1)-x)*(c(3)*x-c(4)*p))-1)/@exp(2*((x(1)-x)*(c(3)*x-c(4)*p))+1))

And yes, supplying initial values might be helpful in terms of convergence. However, you should be careful in using the tanh(x) function, since it takes values between -1 and +1 and saturates quickly (e.g. |x|>3).

[Chris]

Thanks a lot ! I just have to restrict some parameters and I'm done. Already saw a topic in this concern.

All my best,
Chris