Hi vprimali:
I am going to guess that you made a small syntax error when you defined your equation. Make sure that it is entered like this ( with a "*" between the first "x" and the "(" ):
y=1/x*(1+(P1*x)^P2)^P3
On the Edit Function page of the Nonlinear Curve Fitter, set Form to Y-Script or Equations. Also, you will have to enter some initial parameter guesstimates. If you do these things, I think you'll be all set.
Mike
OriginLab
P.S. Note that my original (unedited) post used brackets "[ ]" when, in fact, I should have used parentheses "( )" -- my mistake. Origin 6/LabTalk doesn't seem to care whether parens or brackets are used but brackets wouldn't fly if defining your fitting function in Origin C. Should use "( )".
Edited by - Mike on 08/09/2005 2:13:05 PM |
Van Genuchten
Posted - 08/09/2005 : 03:48:12 AM
