Elegant users forum

Hello,

Function sddspfit seems to return incorrect result of fitting in some cases. Works well for polynomial orders 0,1,2 - but gives constant offset when I add orders of 3 and higher.
The example of data file and script attached (SL6 and SL7 were used)

Thank you!
Ksenia, BINP

Ksenia,

The problem is that the independent quantity (H6) has a large average value compared to its range. This causes numerical precision problems. You can fix this by adding the -autoOffset option, but should realize that the meaning of the fit coefficients is then changed.

--Michael