I always get error -23001 when I try to use the levenberg marquardt VI ?

[Marc-Andre]

I want to make a fit using Planck equation of blackbody on data taken from a spectrometer. I can't make the fit due to error -23001. How can I solve this error ? And by the way, what is a parser in LabView ?

[altenbach]

The parser interprets your formula.

If there is a parser error, it means that the syntax of your formula (model equation) is incorrect. Can you post your equation here?

[Marc-Andre]

thank, I just solve my problem