Constraint in sum of fit functions?

Share icon

How do I apply a constraint for sums of fit functions? For instance, if I am using a routine such as:

FuncFit {{f1,coef1},{f2,coef2},{f3,coef3}}

I want to constrain, say, coef2[2]>0? Is this possible? When using FuncFit for a single function this would be usually specified by the /C parameter and textwave.
You can do it, it's just not convenient :)

The trick is that you use the /C flag and text wave just like you would if the coefficient waves were concatenated into one long coefficient wave. So, let's say you have coefficient waves like this:

coef1 = {1,2,3,4}
coef2 = {-1,-2, 4}
coef3 = {5,6}

and you want coef2[2] > 0. Since there are four coefficients in coef1 and it is first in the list of summed functions, the Kn you would use in the constraint expression would be K5. So your wave would have one row with K5>0.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com

January 24, 2012 at 02:53 pm - Permalink

josh_ld wrote:
Any plans to incorporate a slick front end to this this MPF2?

You mean a slick front end for applying constraints in Multipeak Fit? It's on the list. Lots of projects like this are on hold while we rip Igor apart and rebuild using more modern APIs.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com

January 25, 2012 at 08:48 am - Permalink