Hi, I tried to use interp1 function to extrapolate a dataset consists of 1600 points (read from Excel sheet). The variable extracted the data and can plot it easily. However, the resulted plot of interpolated and extrapolated data is linear!!!!
Here is the code I used for testing:
data=xlsread('DATA.xls','A2:A1601'); x=[1:1:1600]; xi=1:1:1700; z=interp1(x,data,xi,'spline','extrap');plot(x,data,'or',xi,z);
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