Mathcad Help - Lookup and two way linear interpolation

Forum|Forum|12 years ago
July 19, 2013
1 reply
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Hi all,

I am a new user to Mathcad and I have came up against a very tough problem.

In the attachment (and image below) there is a table that looks up a value of Cy for a given K and M simple. The problem comes when the values for K and M are not a whole numbers for example - K=32 and M=0.23 then the value for Cy is in the range of 1.63 - 2.3. You need to interpolate between the four figures.

Cy will actually equal - 1.7348

I am looking to produce a Mathcad function that would allow me to look up any value of K and M.

You help is much appreciated.

Kind Regards

Chris.

1_DNV-RP-F109---TABLE-3-9.xlsx

Statistics_Analysis

Best answer by Werner_E

This should help:

W

Werner_E

25-Diamond I

This problem often comes up here in the forum and as often was solevd.

The >=140 would need some special treatment but thats not difficult, setting K to 140 for every value gretaer before the interpolation.

You wrote that you are after linear interpolation in the subsject, but you don't specify which version of Mathcad you use. Maybe you attach your Mathcad sheet to show what you have tried so far.

A thread of the near past which might be of interest to you:

http://communities.ptc.com/message/208694#208694 (see the function f_look() in the MC file)