Subject: Re: [nmr_sparky] some problems about relaxation
From: Thomas Goddard
Date: Apr 20, 2006

Previous: 106

Hi JLee,

Sparky fits a decaying exponential Aexp(-Bt) to the peak heights
using a least squares fit. The sum of the squares of the differences
between experimental peak heights to the exponential curve is
minimized. Perhaps the modelfree curvefit script uses a different
optimization criterion.

You might want to try a test to see if both programs give the same
result when the peaks lie exactly on a decaying exponential. Calculate
3 points on a decaying exponential with a calculator. You can run
Sparky fitting with these values by setting the volumes of 3 peaks
manually using accelerator ot (ornament properties), then asking to
fit peak volumes. I think the peaks will have to be assigned. Then
try the same 3 values in modelfree curvefit.

Tom