Creating a 3D lookup table from CSV

[antje668]

It works exactly as how I want it. Thanks a lot.

If i would want to interpolate the output value if lets say I give an input which is not in my list (for example x =15e+7, y = 4700, and z = 0.5, here Y is the value which is not included in my inputs. If i then want the output to be an interpolated value, could a solution be to change the threshold block to a interpolate 1D array block? If i give the aforementioned input right now the output is instead rounded to a nearby output value from the CSV file 🙂

[altenbach]

You need to do a trilinear interploation based on your fractional indices. Not trivial.

(See also this idea and its links)

Alternatively, you could fit your 3D data to a reasonable model (if one exists), and then get the value of any point in space based on model and parameters.

[antje668]

Ok I will look into that!

One more maybe way more trivial thing is that my output right now rounds to fewer decimals then I want even though it is a 64 bit double. If I for example want a output value of 41.577854 it rounds to 41.578 even though a 64 bit Double can handle way more than just 3 decimal points

[altenbach]

You can change the format of the display to anything you want (right-click...display format...). The value cannot be more precise that whatever you had in your data file, of course. 😄

(The display is a purely cosmetic. The underlying data is always full precision)

[antje668]

Ok but in my data file I have the value of 41.577854 which LabVIEW  rounds to 41.578 instead.

[altenbach]

[antje668]

Ok I understand! You have been more than helpful to me, thanks a lot! Which post is most convient to mark as a solution? I will of course also both give you and @LLindenbauer kudos! 🙂

[altenbach]

You can mark more than one as solution, I think.

[antje668]

Maybe this solution could be realized by just connecting LabVIEW with Matlab and just the "interp3" function from there? Then Matlab can do the work for me.

[altenbach]

... or you could just use my trilinear interpolation I linked earlier. 😄

(of course you need to calculate the fractional indices by thresholding into the three 1D arrays as already shown)