| T O P I C R E V I E W |
| Zuffy |
Posted - 09/30/2006 : 4:49:03 PM
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,
Thanks |
| 2 L A T E S T R E P L I E S (Newest First) |
| Zuffy |
Posted - 10/03/2006 : 01:22:38 AM
Thanks. Tried your method and it worked great. |
| easwar |
Posted - 10/02/2006 : 3:57:06 PM
Hi Zuffy,
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).
Note that only linear constraints are supported.
Easwar
OriginLab
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