From: Dr. Johannes Zellner <johannes@ze...> - 2008-03-09 18:59:17
I just had a look at the thin plate splines code. Apparently, this is
1. Suggestion: I recognized calls like
splines_kernel(sqrt(dx*dx + dy*dy))
where splines_kernel(double h) essentially returns
h * h * log(h).
I'd suggest to rewrite this to
splines_kernel(dx*x + dy*dy)
where splines_kernel(double h) then returns
h * log(h) * 0.5
This saves one sqrt per call and the factor 0.5 could even be moved to outside
2. Are there any other useful (faster) kernels? E.g. a kernel with no
expensive function like log()?
Dr. Johannes Zellner <johannes@...>