Geraldine,
They really are the same fit, try...
range(fitted(b)-fitted(b1))
[1] -3.333782e-10 4.173699e-10
... for example.
The edf differences are just down to differences in how identifiability
constraints are handled in the two cases. For b1 the smooths of x2 do
not have centring
Dear all,
I'm using the mgcv library by Simon Wood to fit gam models with interactions
and I have been reading (and running) the factor 'by' variable example
given on the gam.models help page (see below, output from the two first models
b, and b1).
The example explains that both b and b1 fits
2 matches
Mail list logo
