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gmr
2009 Feb 07
1
paraPen in gam [mgcv 1.4-1.1] and centering constraints
...e the same
centering constraint on user-defined penalized coefficient groups like
it is implemented for the spline smoothing terms. The reason is that I
have actually a factor coding different regions, and the penalty matrix
results from the neighborhood structure in a Gaussian Markov Random
Field (GMRF). So I can't choose one region as the reference category,
because then the structure in the other regions would not contain the
same information as before...
Is there a way to constraint a group of coefficients to sum to zero?
Thanks in advance,
Daniel Sabanes