I was wandering if there was a way to force the fit of a nonlinear curve (such as an exponential decay) to pass through the origin. I really appreciate any help,
You can do this by placing a linear constraint, if applicable to your equation.
Thus for example you are fitting with the ExpDec1 function, which is of the form y=y0+A1*exp(-x/t1) forcing the curve to go thru (0,0) would mean: 0=y0+A1
In the NLSF tool, use the menu Options->Constraints and in the edit box at bottom, enter: A1+y0=0; and then check the "Enabled" check box and continue to fit. This constraint should then force curve to go thru (0,0).
forcing a fit
Posted - 09/30/2006 : 4:49:03 PM
