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Re: curvefit [message #44403 is a reply to message #9041]

Tue, 14 June 2005 09:16

Paolo Grigis
Messages: 171
Registered: December 2003

Senior Member

nolan.smith1@gmail.com wrote:
> I spoke too soon!
> So I have set up my function:
> (the model I am trying to fit is y=a/((1+(x/b))^2) )
>
> FUNCTION myfun,X,P
> RETURN,P(0)/(1+(X/P(1))^2)
> END
>
> and then I try to run
>
> result=MPFITFUN('myfun',x,y,0.5,0.01)
The 4th argument should be an array with the errors on y and the
5th argument an array with the estimates for the parameters,
so try something like:

err=replicate(1,n_elements(x));constant errors in y
par=[0.5,0.01];parameter estimate

result=MPFITFUN('myfun',x,y,err,par)

>
> Where x,y are my x,y coordinates of the data that I am trying to fit,
> 0.5 is the first guess for P(0) and 0.01 is the first guess for P(1).
> As you guessed it is not working. What am I doing wrong?
>
> Thank you,
> Nolan
>

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[Message index]

		Curvefit By: zanotti on Wed, 21 May 1997 00:00
		Re: Curvefit By: thompson on Wed, 21 May 1997 00:00
		Re: curvefit By: David Fanning on Tue, 07 January 2003 20:13
		Re: CURVEFIT By: Craig Markwardt on Wed, 02 June 2004 11:40
		Re: CURVEFIT By: K. Bowman on Wed, 02 June 2004 08:56
		Re: curvefit By: Paolo Grigis on Tue, 14 June 2005 09:16
		Re: curvefit By: nolan.smith1 on Tue, 14 June 2005 08:20
		Re: curvefit By: nolan.smith1 on Mon, 13 June 2005 21:02
		Re: curvefit By: nolan.smith1 on Mon, 13 June 2005 20:07
		Re: curvefit By: Craig Markwardt on Mon, 13 June 2005 15:24
		Re: curvefit By: kashyap on Mon, 13 June 2005 14:50
		Re: curvefit By: nolan.smith1 on Mon, 13 June 2005 12:59
		Re: curvefit By: Benjamin Hornberger on Mon, 13 June 2005 12:46

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