erf(x) fitting

[Soran]

Hi,

I should fit my data with an erf function. I tried to use Nonlinear Curve Fit VI but it does not accept erf(x) as a string (it gives an error that the function is not valid). I read National Instrument tutorial in which it is mentioned erf(x) can be used for fitting (see the last page here: http://home.iitj.ac.in/~sy/sy/satfiles/CurveFittingTutorial.pdf).

Can anyone please help me about this?

Thank you,

Soran

[johnsold]

That link does not work for me.

The fitting VI often work better if you use the VI version rather than the formula version. Create a VI from the template linked in the detailed help for the fitting VI. Place the LV erf function in that VI. The LV functions are much faster than the formula evaluation VIs and that can become important in a fitting process where the function needs to be evaluated many times.

Lynn

[altenbach · Accepted solution]

Maybe this thread can give you some ideas.

[altenbach]

---

@johnsold wrote:

That link does not work for me.

---

The link works if remove the ")." at the end.

[Soran]

Thank you guys