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Minimization: Determine a constant across data sets [message #79843]

Thu, 05 April 2012 19:42

Justin Cantrell
Messages: 5
Registered: May 2010

Junior Member

Hi all!

I have several data sets that follow the form:

data = A* e^(-t/t0)+ y

I suspect EVERY data set to have the same t0, but different A & y values. (ie: (A1,y1),(A2,y2)...)
I can use MPFITFUN to fit A,t0 and y, but the routine determines a least chi-squared such that t0 is different for every data set.

It would seem simple enough to fix t0 in MPFITFUN if I knew what the value was beforehand, but I don't :) Is there a way to minimize t0 across several data sets such that A & y are allowed to vary, but t0 is tied to every data set?

I tried doing this in grids, but it was very computationally time consuming to search an unknown gridspace of t0 in an double for loop.

Thanks!
Justin

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