what cspline() returns and how interp() works? 2 dimensions Mxy and Mz

Forum|Forum|2 years ago
September 18, 2023
2 replies
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Initially posted in this topic

Hi all,

i can understand this for single dimension vx and vy, but what about 2 dimensions Mxy and Mz? Could anyone explain what cspline() returns and how interp() works? Thx in advance!

Lert

Note: i use mathcad 15.

Other

T

terryhendicott

21-Topaz II

Hi,

Here is the Mathcad 15 Quicksheet for cspline(). It illustrates a 2D cubic spline.

Have added a 1D cubic spline example on Right Hand Side.

Cubic spline interpolation passes a curve through a set of points in such away that the first and second derivatives of the curve are continuous across each point. This curve is assembled by taking three adjacent points and constructing a cubic polynomial passing through those points. These cubic polynomials are then strung together to form the completed curve.

Interp() uses the cubic polynomial curve coefficient values returned by cspline() to interpolate the cubic polynomial equations between points defining the cspline.

Cheers

Terry

1_230918-CSpline.zip

L

LertPianapitham

Author

5-Regular Member

Thanks @terryhendicott , but i would like to know, how could i get the polynomial equation(s) as shown in the original post. Could you pls. explain this for bi-cubic spline as well?

W

Werner_E

25-Diamond I

Your question obviously stems from an older thread and was turned into a new thread by a moderator. Unfortunately the links he inserted refer to this thread and not to the older one.

I already notified the mods and asked them to fix this. But maybe in the meantime you can provide the link to the older thread you are referring to when you write "as shown in the original post".