## Can we do simultaneous fitting for two functions with Igor

cheney
Posts: 4
Joined: 2012-02-24
Location: Australia

Hi Everyone,

I am wondering how to do fitting two (or multiple) functions simultaneously with Igor pro. I have been familiar with basic fitting functionalities in Igor pro and I've also read the manual carefully. It seems the manual doesn't address this problem. Hope to get a help here:-)

Put a trival example to make my question clear. Say, we have two waves with same scaling and dimension: wav1 and wav2. Each wave can be fitted using a single variable function, f1 and f2. The two functions share some parameters but have independent parameters as well, f1(a1,a2,a3), and f2(a1,a2,a4). One can certainly fit one wave first and use the resultant parameters for the subsequent fitting of the second wave. However, a better way should be fit them simultaneously so that the two waves can have the same weighting to all parameters.

Thanks
Cheney

[ last edited April 29, 2012 - 05:14 ]
bech
Posts: 54
Joined: 2007-10-20

cheney wrote:
Hi Everyone,

I am wondering how to do fitting two (or multiple) functions simultaneously with Igor pro. I have been familiar with basic fitting functionalities in Igor pro and I've also read the manual carefully. It seems the manual doesn't address this problem. Hope to get a help here:-)

Put a trival example to make my question clear. Say, we have two waves with same scaling and dimension: wav1 and wav2. Each wave can be fitted using a single variable function, f1 and f2. The two functions share some parameters but have independent parameters as well, f1(a1,a2,a3), and f2(a1,a2,a4). One can certainly fit one wave first and use the resultant parameters for the subsequent fitting of the second wave. However, a better way should be fit them simultaneously so that the two waves can have the same weighting to all parameters.

Thanks
Cheney

See Analysis / Packages / Global Fit.

cheney
Posts: 4
Joined: 2012-02-24
Location: Australia

bech wrote:
cheney wrote:
Hi Everyone,

I am wondering how to do fitting two (or multiple) functions simultaneously with Igor pro. I have been familiar with basic fitting functionalities in Igor pro and I've also read the manual carefully. It seems the manual doesn't address this problem. Hope to get a help here:-)

Put a trival example to make my question clear. Say, we have two waves with same scaling and dimension: wav1 and wav2. Each wave can be fitted using a single variable function, f1 and f2. The two functions share some parameters but have independent parameters as well, f1(a1,a2,a3), and f2(a1,a2,a4). One can certainly fit one wave first and use the resultant parameters for the subsequent fitting of the second wave. However, a better way should be fit them simultaneously so that the two waves can have the same weighting to all parameters.

Thanks
Cheney

See Analysis / Packages / Global Fit.

Thank you very much, bech.

Posts: 836
Joined: 2007-06-29
Location: United States

And I'd like to add that there's a demo experiment for Global Fit: File->Examples->Curve Fitting->Global Fit Demo.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com