Mathcad Help - Lookup and two way linear interpolation

[cdoherty]

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.

[Werner_E]

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)

[cdoherty]

Hi Werner Exinger,

Thank you so much for your reply. I am using Mathcad 15 and haven't really got anything to show yet.

I will have a look through the thread you suggested to see if I can come up with something before I send it to you.

Thanks again.

Chris.

[Werner_E · Accepted solution]

This should help:

[cdoherty]

Thank you very much for your help.

Take care and best regards

Chris.

[smungar]

Werner Exinger wrote:

This should help:

Hi,

I would like to do the same but than for table 3-2 of the DNV-RP-F109 in mathcad prime 3.0. However, I am having some difficulties adapting the script to mathcad prime 3.0 see picture. Help is appreciated

[MikeArmstrong]

My effort in the attached. I manually typed the tables into Mathcad.

[smungar]

I am unable to open .xmcd extensions

[MikeArmstrong]

Mathcad Prime 3.0 version attached.

Sorry I do not have time to format it.

[smungar]

Thanks Mike

[MikeArmstrong]

No problem at all. It's nice to see a problem related to my industry for a change