Nonlinear Curve Fit LM Formula String in Labview 8

[trinight]

hi, guys. I write a vi which use Nonlinear Curve Fit LM Formula String. When I run it ,the program says "Syntax error of parser." and I don't know what's wrong with it, so help me,Please. By the way ,you can fill the arrays as you wish.

帖子被trinight在02-11-2006 07:51 PM时编辑过了

[altenbach]

You MUST wire initial estimates for the parameters. Attached modification works just fine.

[trinight]

Thank you, altenbach. you seem to know all about Labview 🙂

[neerajp]

Hello,

I am trying to fit the following equation using Nonlinear Curve fit LM: formula string.

a1+a2*x+a3*x*x+a4*c

where a1, a2, a3 and a4 are the parameters to fit while x and c are independent values. x is wired to X in the Nonlinear curve fit.vi. I have a 1 D array of c values for each x. Could you give me some suggestions on how to include these additional 'c' values in the Model description?

Many Thanks

Neeraj

[altenbach]

Use the version with the VI model and use the data variant to give the C to the model. You can also e.g. interlace x and c into a single 1D array of twice the length. Again, make sure the model knows how to retrieve it correctly.

Since this thread is well over 10 years old, maybe should start a new thread, attach your code, and explain exactly what the problem is.

[neerajp]

Thanks a lot!!! I will try your suggestions and start a new thread for this 🙂