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gawab
USA
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 Posted - 01/24/2006 : 5:37:06 PM
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Origin Version (Select Help-->About Origin): 7
Operating System: win XP
Mr. Buess, Thanks for your help last time. I have one more question.
As per my previous question, I have x and y values for which I am trying to find a curve. The equation for the curve is y=abs(So*(1-2*exp(-x/T1)))+S1 (user-defined function) where So,T1, and S1 are my 3 parameters. Problem is, I am having problems initializing these parameters. When I use "simulate" I can only type in random numbers for these parameters that don't make a curve that approaches my data. What I want is for the system to vary these parameters simultaneously between the upper and lower limits (say, 0 and 5000) so that I get a good fit. What is a way I can get the system to return these numbers so that they approximate my data? Please be as detailed as possible as I am a new user of this program. Thanks,Li
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minimax
351 Posts |
Posted - 01/25/2006 : 01:38:49 AM
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Hi Li,
Origin provides automatic parameter initialization code for all built-in functions. For user-defined functions, you need to add your own parameter initialization code. To open the parameter initializations dialog, choose Scripts:Parameter:Initialization from the NLSF menu.
You can simply enter "guesstimate" parameter values in the parameters group to start the iterative fitting process. Furthermore, you can use code builder to create your own OriginC code to initialize the parameters.
Max
OriginLab GZoffice |
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Initializing parameters