Computational Science people:
The title is the question: exactly how does Matlab's "interp2" command (with the "cubic" option) perform bicubic interpolation? I tried the Mathworks documentation online and I couldn't find the answer there. I found a nice Wikipedia article at http://en.wikipedia.org/wiki/Bicubic_interpolation , but it describes an algorithm that requires values of $f$, $f_x$, $f_y$, and $f_{xy}$, while "interp2" requires only function values, not derivatives. Maybe Matlab estimates the partial derivatives somehow, but I don't know.
My apologies if the answer actually is in the Mathworks documentation, but I looked pretty hard and I couldn't find it.
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depends on whether it is implemented in matlab or not. Sometimes matlab calls functions written in other languages, which it does not have the source code from. In those cases, you may or may not find useful information. it is always worth a shot though. $\endgroup$ – Godric Seer Sep 23 '13 at 2:01