How to make spline basis matrix?

I'm trying to find out how to make a basis matrix of natural cubic splines. That is, I have 256 knots, the integers 1:256, and I want a 256x12 matrix of 12 basis splines defined on the frequencies. What I'm looking for is the Matlab equivalent of the "ns" function in R. (<http://stat.ethz.ch/R-manual/R-devel/library/splines/html/ns.html>) Is this possible?

[Servane Lunven]

If you have found the answer, i would be interested !

Answer 1

[Matt J]

Example1D.m in this File Exchange submission shows how to set up a B-spline basis matrix,

https://www.mathworks.com/matlabcentral/fileexchange/26292-regular-control-point-interpolation-matrix-with-boundary-conditions

You can adapt the same example to any other basis function that you wish, although B-splines are particularly stable as compared to other spline types, so I don't know why you wouldn't use them instead.

[Matt J]

See also,

https://www.mathworks.com/matlabcentral/fileexchange/44669-func2mat-convert-linear-function-to-matrix

[Servane Lunven]

Thanks but what is the kernel?