MATLAB: How to do interpolation in matlab?

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I have attached an excel file, which contains x, y, z data. I want to interpolate the data. Can you help?? (In the data for a particular x at different y value, the z value is different. )

Best Answer

I am not absolutely certain what you want to do.
The row lengths between unique values in the first column are not the same, so using reshape is not an option to create matrices from the data.
One option, if you want to create a uniformly-sampled matrix, is to use griddata to do the interpolation: 
D = readmatrix('data.xlsx');
[Du,ia] = unique(D(:,1));
rowlen = diff(ia);                                  % Changes In ‘x’
xv = linspace(min(D(:,1)), max(D(:,1)), 50);
yv = linspace(min(D(:,2)), max(D(:,2)), 50);
[X,Y] = ndgrid(xv,yv);
Z = griddata(D(:,1), D(:,2),D(:,3),X,Y);
figure
surf(X, Y, Z)
This also plots the result.
Change the code appropriately to get the result you want.
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