Im working with Origin 6.0.
I have some troubles finding the right initial values to do a fitting with a script. I get the error message: "Error: 28036. Try setting parameter 't1' as fixed". When i simply used the fitting ExpDec1 and iterate i got this error quite frequently. So i tried to initialize the parameter with the more robust simplex method. But even that doesnt always work. The function doesnt seem to be able to find the optimum then and produces huge values for the parameter.
Here is a section of my code.
nlsf.init();
nlsf.func$=ExpDec1;
nlsf.constr$="";
nlsf.v1=0;
nlsf.P1=0.63;
nlsf.v2=1;
nlsf.v3=1;
nlsf.fitdata$=exp_kWerte;
nlsf.funcx$=exp_Conc;
nlsf.dataBegin=1;
nlsf.dataEnd=N+2;
nlsf.simplex(100000);
nlsf.iterate(2000);
nlsf.xMode=2;
nlsf.funccol$=exp_FITFINAL;
nlsf.makecurve(func);
I have no idea how i can come around this. If i copy the data to be fitted into a seperate work sheet and use the plot-> scatter function and then do a manual fitting with the analyze -> fit exponential decay -> first order everything works just fine. Any help would be appreciated.
Thx,
Mathias
