chtan23 Posted July 18, 2006 Report Share Posted July 18, 2006 I have a problem with my non linear curve fitting program I have attached below my program. the equation used has y on both on the left and right hand side of the main equation shown below y = 3.4 - 6E-10*((exp(1.602 177E-19 *(x+(y*a))/(1.380 6505E-23 *(273+25)))-1) -((x+y*a)/b)) the program does not run and the a and b coeefficient could be determine. I want to place IL, T and Isc as variable numbers how to place a input on the front panel to insert the value for Isc and T and IL if this equation is used in the string constant This makes the equation y = Isc- IL*((exp(1.602 177E-19 *(x+(y*a))/(1.380 6505E-23 *(T)))-1) -((x+y*a)/b)) Download File:post-5613-1153226107.vi Quote Link to comment
chtan23 Posted July 19, 2006 Author Report Share Posted July 19, 2006 No one is able to do it ? OR advice me ? I have added in the datas required Quote Link to comment
crelf Posted July 19, 2006 Report Share Posted July 19, 2006 No one is able to do it ? OR advice me ? I have added in the datas required Excited that this thread got a reply? Don't be - read this instead... Quote Link to comment
AnalogKid2DigitalMan Posted July 19, 2006 Report Share Posted July 19, 2006 Related discussion here http://forums.ni.com/ni/board/message?boar...ding&page=1 Quote Link to comment
ahlers01 Posted July 19, 2006 Report Share Posted July 19, 2006 No one is able to do it ? OR advice me ? I have added in the datas required I had a look at your equation. If I read it correctly, you can substitute z:=x+a*y and then bring the equation to the form x=f(z). You could then try to use this for non-linear fitting, treating x as the dependent and z as the independent variable. Also I would recommend you normalize your values in such a way that reasonably sized coefficients occur, not ones which differ by 23 orders of magnitude. That would probably help to avoid numerical errors -Franz Quote Link to comment
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