LabVIEW
how can you perform curve fitting to a 2d array and find the maximum?
Where did you have that example tucked away, altenbach? 
While trying to provide a response I had come across this other example you had, which looks like an early version of this one. However, it, like this one, requires a mathematical model, and my assumption (right or wrong) was that the user didn't have one so I didn't mention it. Instead, I opted to suggest just the raw polynomial curve fit. Still, I should have suggested that example regardless in case the user did have a mathematical model. Thanks for pointing it out.
While trying to provide a response I had come across this other example you had, which looks like an early version of this one. However, it, like this one, requires a mathematical model, and my assumption (right or wrong) was that the user didn't have one so I didn't mention it. Instead, I opted to suggest just the raw polynomial curve fit. Still, I should have suggested that example regardless in case the user did have a mathematical model. Thanks for pointing it out.
smercurio_fc wrote: Where did you have that example tucked away, altenbach?
I submitted it to NI, so it should be available somewhere as part of the NI-week extras. I was just looking at it and found that there is a problem, possibly with the 3D graph activex component and I get a crash under some conditions (under 8.5.1). I want to research this first before posting here again.
If you look at the other link I posted (3DPoly_Newdata.llb), it does a plain 2D polynomial of arbitrary order (See picture).
Message Edited by altenbach on 06-27-2008 10:40 AM
Well, all you need is three 1D DBL arrays of equal lenght (x, y, z) and substitute for the three 1D arrays that come out of the index array connected to the "select x, y, z" controls. The rest should fall into place. (e.g. delete the two "index array", turn CurrentX, CurrentY, CurrentZ into controls. and wire in your array data in some way.
There is currently al lof of extra code to be able to select any of 4 choices for any of the 3 axes. (bug alert: there are even a few wires missing!, e.g. going to the idexing of the axis names).
Anyway, you don't need all that!
As I said, since your x and y form a regular grid, things could be simplified further. All you need is X0, dx, Y0, dy, and a 2D Y array. This would require some reworking though. 😉
The calculations is done in full DBL precision. If you want to see more, right-click the indicators and change the dislpay format to show more digits.
You actually are, look at the arrays. You need to remove the elements that are zeroes and truncate the arrays. Where are the zeroes coming from? Do you have extra empty lines in your datafile perhaps?
jaysmall wrote:
Beyond the domain of the information I'm inputting, it is still calculating best fit. So I'm guessing that it thinks I'm also inputting a value of (x y z) = (0 0 0), which kind of stinks...
Message Edited by altenbach on 06-27-2008 02:45 PM
