How to retain duplicate while using ScatteredInterpolant

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Aristo
Aristo on 2 Sep 2017
Answered: Francesc Purroy on 12 Nov 2018
I want to retain duplicates when using ScatteredInterpolant because I am getting warning:"Warning: Duplicate data points have been detected and removed - corresponding values have been averaged. "

Accepted Answer

John D'Errico
John D'Errico on 2 Sep 2017
Edited: John D'Errico on 2 Sep 2017
1-d is sufficient to explain here.
x = [1 2 3 3 4 5];
y = [1 2 3 4 5 6];
There is a replicated x, with two distinct values of y. Exactly what do you think "retaining the duplicate" means here? What value of y should be interpolated when x==3?
A property of interpolation is that for any given x, if one of the original data points is interpolated, you should get out exactly the same value as went in. (At least, exact to within floating point trash.)
  2 Comments
Walter Roberson
Walter Roberson on 2 Sep 2017
You have not answered the question about which value of y should be interpolated.

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Francesc Purroy
Francesc Purroy on 12 Nov 2018
In some cases you can have a set of x and y data where the values of x and/or y are repeated as Aristo was showing. A simple way around is to add some noise to your data as with randn then ScatterInterpolant does not consider the values to be equal and it works for me.

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