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Can someone provide me reference regarding the mathematics of the "approx3d" function? Does this function apply "trilinear interpolation"?

David
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  • Is `approx3d` part of some common library like [`Numpy`](https://www.numpy.org/) or [`Scipy`](https://www.scipy.org/scipylib/index.html)? The answer is likely specific to an implementation. – Andrew F Dec 23 '18 at 20:37
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  • @Someprogrammerdude Isn't my question correct? – David Dec 23 '18 at 20:42
  • @AndrewF This function is form "oce". – David Dec 23 '18 at 20:43
  • @David And what is "oce"? – melpomene Dec 23 '18 at 20:52
  • @melpomene It's the corresponding library. – David Dec 23 '18 at 20:58

1 Answers1

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The only approx3d implementation I could find is a library in R, here and indeed it says it uses "trilinear approximation."

The simpler case would be "bilinear interpolation". Given two points on a plane, the interpolated middle-point is just the average of those two given points.

Trilinear interpolation is similar, except that in three dimensions you must average three points (not two) and average their three coordinates. You may notice that if (for example) both points have the same X-coordinate (say x=0), then the problem reduces to bilinear interpolation again.

Andrew F
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  • Thank you for your answer. Indeed I want to understand the mathematics behind this function. But I can't find relevant document. – David Dec 23 '18 at 21:00