help for creating a 2D lookup table .

I want to create a table F so that I could searh values ffrom the table by F(x,y). When I am using the scatteredInterpolant , some points i get inf values. Why it happens ??? for the neighboring values around x y , I got the right values. Thank you so much ！！！！！！！！！！！！！！！！！！！

[Cameron B]

We are unable to help unless you post your table and the value(s) you would like to interpolate.

[Walter Roberson]

Suppose that you had two points (realmin, 0) and (3*realmin,10) and you ask to interpolate at 2*realmin. Δy = 10, Δx = 2*realmin. Δy/Δx = 5/realmin. But 1/realmin is the largest non-infinite number, so that is 5 times (almost infinity) which is infinity.

Therefore it is possible with locations very close together for interpolation to generate inf even though none of the data is inf or nan.

Answer 1

[Walter Roberson]

My comment shows how inf can occur for non-infinite values even when examining data inside the region.

However, probably what is happening for you is that you are asking for values at a location outside the maximum triangulation of the scattered data, and you have your interpolation configured to return inf in that case.

More typical is for people to leave interpolation at the default, in which case requesting values outside of the triangulation gets you nan instead of inf.

[vvf vvff]

Thank you so much !!! I guess so. So I could only get the values inside the limits of the scattered data ??

[Walter Roberson]

Look at the options for scatteredInterpolant: you can change the interpolation method.

[vvf vvff]

Thank you ! I haven't noticed that