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Question

2d linear interpolation

Forum|Forum|8 years ago
March 5, 2018
1 reply
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Dear all,
I'm facing again a problem with linear 2D interpolation.
In this case I tried to see if the results of direct and inverse interpolation coincide.
z=f(x,y) and y=f(x,z).
Unfortunately, they don't.
Could you please help me in finding the solution of this problem?
Attached you see the mathcad file.

Thank-you very much for your support.

Regards.

Enrico

1_Direct-and-inverse-linear-2D-interpolation.zip

Other

25-Diamond I

Sorry, but I see no reason why the two diagrams in your sheet should coincide.

Your first table yields a value for cycles of 35309 if force=16574 and ratio=0.2.

Your second table suggest a cycle value of just 100 for the same values. Obviously different functions.

Author

1-Visitor

Dear Werner,

Thank-you very much for your reply.

You are right. I've sorted out the file. Now it should be clearer.

I still find some difficulties by interpolating the data.

I really appreciate your support!

Regards.

Enrico

1_Direct-and-inverse-linear-2D-interpolation_1.zip

25-Diamond I

Why are there value which do not correspond?

Is that due to the fit function you use to provide the inverse function?

I'm not sure, but it looks like the two data sets don't stem from the same function.

Don't think that the interpolation is responsible for the big differences.

Why are there value which do not correspond?
Is that due to the fit function you use to provide the inverse function?

below you find the function.

"log" means logarithm to base 10 as in Mathcad?

sigma is Force in your sheet, N is Cycles, k is LoadRatio ?

Whats the value of sigma.A?

BTW, If you have a function, why would you need interpolation?