Global fit. Easy modifications in the data set, Initial Guesses etc.

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Fri, 02/10/2017 - 02:01 am

Hi all,

I use the Global Fit package. Once you have run the Global fit over a first range of data, it would be very handy to be able to keep the initial guess for the remaining datasets once you add or remove one (or more) dataset. Up to now, if your run the global fit and want to remove or add a data set, you have to re-write all the Initial Guesses in the "Coefficient control" section, which is a real pain...

Also, even if I wrote a procedure to create the InitialGuess wave accordingly, I think this process should be improved.
And using the Global fit in the command line seems really complicated to me (even though I understood there are possibilities, the help requires a proper detailed example, according to me).

This package is very very nice though, thank you for your great support and careful attention,

Tijead
I have to say that Global Fit really isn't intended to be used from the command line. It requires construction of so many supporting data structures that it simply isn't practical. With great effort, you can write your own interface for it, something that other users have done.

Since I'm working on my phone right now I can't look up the details. It is possible to save your coefficient wave and load up the initial guesses from it. This is described in the help- just click the help button in GUI.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com

February 10, 2017 at 09:44 am - Permalink

This is not exactly what you're asking for, but is related. I use a wrapper for FuncFit that's hard-wired to a particular subset of the functionality of Global Analysis package. I often fit a bunch of pseudovoigt peaks to multiple spectra, and I wanted to be able to use the mouse to adjust my initial guesses, in a similar way to the Multi-peak fit procedure. Each peak has 4 parameters that can be adjusted with the GUI:

// For fitting n pseudovoigt peaks to each of N waves.
// Amplitude is unique to each peak, but each set of
// N peaks has constant position, width and shape parameters.

// Command (or control) click to add a peak at x position of mouse cursor.
// Mouse-over peaks and click to select; use mouse to move peak position,
// mousewheel up-down to adjust amplitude, mousewheel left-right to adjust shape,
// shift + mousewheel up-down to adjust width parameter

Maybe this is of use to someone. I'll attach the procedure file here. Please read the comments at the top of the procedure file before using.

tony
MultiWaveFit.ipf

February 14, 2017 at 08:53 am - Permalink