- interpolation on data point
- The derivative inside the interval does not change sign (hermit specific), but this constraints are enforced internally
why does not "pchip" requires derivative values as input
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In my understanding, Piecewise Cubic Hermite polynomials requires both values and derivative values at each point.
Matlab "pchip", https://www.mathworks.com/help/matlab/ref/pchip.html, is exactly Piecewise Cubic Hermite polynomials, but does not require derivatives.
So why no derivatives values are needed as inputs for "pchip"
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Answers (1)
Bruno Luong
on 20 Oct 2023
Edited: Bruno Luong
on 20 Oct 2023
Since the derivatives are computed internally as with general polynomial picewise functions.
It satisfies :
If user imposes the derivarive at the break points then it might not be able to satifsfy the second condition.
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Bruno Luong
on 20 Oct 2023
Edited: Bruno Luong
on 20 Oct 2023
"... which is by imposing monotonicity. "
Exactly
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