MATLAB: How to interpolate a data set to fill a missing point in a vector using MATLAB

griddataholeinterpolateMATLABmissingpoint

How can I interpolate a data set to fill a missing point in a vector using MATLAB?
If I have values for a function on many of the data points on a grid and want to fill in the values of that function for the missing data points on the grid, what function should I use, and how should I set this up?

Best Answer

The following code evaluates the sample function
 f(x,y,z) = x+2*y+4*z
on most of the integer-valued grid points on the unit cube, and uses those function values to interpolate the function value on an integer-valued grid point for which we do not have the function value.
% Generate data for the unit cube
[xx,yy,zz]=ndgrid(-1:1,-1:1,-1:1);
% Combine the three individual coordinates into a matrix
R=[xx(:) yy(:) zz(:)];
% Remove the entry for (1, -1, 1)
R(23,:)=[];
% Calculate a function on the given points
v = xx.*yy+2*xx.*zz+4*yy.*zz;
% Remove the point corresponding to (1, -1, 1)
v = v(:);
v(23, :) = [];
% Interpolate
% The duplicate entry as the third argument is due to
% a bug in griddatan with respect to row vectors as third
% input arguments
s = griddatan(R, v, [1 -1 1;1 -1 1])
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