multiple interp1 without loop

Hi,

interp1 handles the following input and output: Vq = interp1(X,V,Xq)

I have X, V and Xq that each have a dimension of 12 rows by 10^5 columns.

I'd like to carry out interp1 10^5 times, treating each column of data in X,V and Xq as unique datasets in interp1, but Matlab requires that input X is a vector. So it is, therefore, not possible to do the following, because X is an array in my case:

Vq(:,1:10^5) = interp1(X,V,Xq)

I could of course do a loop:

Vq = NaN(12,10^5);
for i = 1:size(Vq,2)
    Vq(:,i) =  interp1(X(:,i),V(:,i),Xq(:,i))
end

That works, but it is super slow.

Does anyone know of a way to do this without implementing a loop, in a way that is significantly faster than a loop?

I realise that I may be asking the impossible here.

edit: would sub2ind help me out here?

Thanks,

Bryan

Answer 1

[Stephen23]

Try using a loop with interp1q.

[Stephen23]

sjohuvud's "Answer" moved here:

Thanks for the tip. Unfortunately interp1q is outdated and no longer included in my version of MatLab. As far as I can see it is the same as interp1 with linear interpolation (i.e. the default setting for interp1. It also has the same limitation of input X needing to be a vector. Do you think interp1q would be slightly faster in the loop because it is simpler?