When does 'interp1' function give 'The grid vector must contain unique points' error?

When does 'interp1' function give 'The grid vector must contain unique points' error?

Answer 1

[MathWorks Support Team]

This error comes when there are duplicate points in input to 'interp1'.

You can remove duplicates using 'unique' function.

Example:-

>> [x, index] = unique(x); 
>> yi = interp1(x, y(index), xi);