Re: [OctDev] Matlab compatiable spline/csape

[Paul Kienzle]

On May 17, 2006, at 4:51 AM, David Bateman wrote:

> However, I have one compatibility issue in the case where y is a 
> matrix or an NDArray. Currently the octave-forge spline function 
> allows  an n-by-d matrix to be passed for y where n is the length of 
> x, and the matrix y is treated column by column, whereas the matlab 
> function allows an NDArray of the form d1-by-d2-by- ... -dk-by-n which 
> is exactly the reverse. I can probably support both in the majority of 
> cases, however ppval and mkpp would need to be modified to store 
> and/or determine which is used. Alternatively, just using the matlab 
> syntax would keep mkpp and ppval pretty much identical to what they 
> currently are (with minor mods for NDArrays). Should I attempt to 
> support both formats for NDArrays, or should I just drop the current 
> octave-forge way of treating Matrixs y?

Drop the current octave-forge way. Don't support both because it is 
ambiguous.

The help for Matlab indicates that the spline interpolation direction 
is the transpose of interp1, so it is a documented misfeature.  Since 
most other functions operate on columns by default I think the interp1 
behaviour is better, however the consensus seems to be that we will put 
up with minor annoyances such as this for the sake of compatibility.

- Paul