Question

I have two arrays – X points and Y points. X array have some spaces (e. g. [0 1 2 6 7 8]), and Y array contains only values for that Xes. I’ve got that array as a local maxima from wavelet transform. I can plot it with plot(X,Y)

Now I want to get Y’s on linspace – Y must contain values for any X from 0 to 8. I want to have the same plot plot(Y) as the previous plot(X, Y).

How can I do this?

Answer 1

It looks like you want to perform interpolation

xPts = [0 1 2 6 7 8];
yPts = ...

xPlot = 0:1:8;
yPlot = interp1(xPts,yPts,xPlot,'cubic')

plot(xPlot,yPlot)

Check the documentation for interp1 for the different interpolation schemes.

If there are repeated x-values, you can average the corresponding y-values

   xPtsRep = [0 0 1 2 6 7 7 8]
   yPtsRep = ...

   [xPts,~,xIdx] = unique(xPtsRep);
   yPts = accumarray(xIdx,yPtsRep,[],@mean);