MATLAB: Interpolation of complex input

complex data interpolation

I tried to use griddata for interpolation of complex data (The Y vector is complex). But it seems that griddata cannot work with complex input. Is there any alternative? Thank you in advance.

Best Answer

You cannot interpolate the real and imaginary parts separately?

help real
help imag

Then put the result back together.

Related Solutions

MATLAB: Does the INTERP1 function in MATLAB handle complex data with the “cubic” method

This enhancement has been incorporated in Release 2006a (R2006a). For previous product releases, read below for any possible workarounds:

The cubic interpolation algorithm is not intended for complex data and hence does not behave well under certain circumstances when the data is complex. As a workaround, use the spline interpolation instead.

Y_spline = interp1(X,Y,Xi,'spline');
plot(X,abs(Y),'b',Xi,abs(Y_spline),'r')

Alternatively, you can split Y into real and imaginary parts, and then interpolate.

Yr = real(Y);
Yi = imag(Y);
Y_cubic = interp1(X,Yr,Xi,'cubic')+i*interp1(X,Yi,Xi,'cubic');
plot(X,abs(Y),'b',Xi,abs(Y_cubic),'r')

MATLAB: How to perform interpolation on complex data using MATLAB

The GRIDDATA function can be used to interpolate complex Z-data. Consider the following example:

xi = [2;3;-1;-5;1];
yi = [1;2;-4;-1;-2];
zi = [5+2j;1-j;2+4j;-7-3j;-1+6j];
xj = [-1;2;3];
yj = [3;-2;4];
zj = griddata(xi,yi,zi,xj,yj,'nearest')

Here, you can use the nearest neighbor method, using the 'nearest' argument. For more information on GRIDDATA, type

doc griddata

at the MATLAB prompt.

Note that the GRIDDATA function cannot handle complex X and Y-data.

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Related Solutions

MATLAB: Does the INTERP1 function in MATLAB handle complex data with the “cubic” method

MATLAB: How to perform interpolation on complex data using MATLAB

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