[Ifit-users] Fitting a piecewise function

[farhi]

Hello Morten,

You can probably try something like:

>> f1=gauss;
>> f2=lorz;

>> f3 = (f1.*'x>=0') + (f2.*'x<=0')

where we first set the two separate functions, then assemble them with 
a multiplication with a boolean on the 'x' axis values, and add the two 
parts.

then f3 is what you need.

Emmanuel.

Le 2013-06-28 11:35, Sales, Morten a écrit :
> Dear iFit users
>
> I have a dataset that I would like to fit, and I was hoping that I
> might be able to get help from this mailing list.
>
> I would like to fit a piecewise function, so for one x-range, the
> data should be fitted by function 1, for the the next x-range it
> should be function 2, etc.
>
> The functions are 'knotted' together so that the end point of one
> function corresponds to the start point of the next.
>
> Among the fitted parameters I would also like to have the length of
> an x-range where the function is constant.
>
> Is this something I can do with iFit?
> (I run iFit-1.3.1a in MatLab R2012a in Mac OS X 10.7.5)
>
> Best Regards,
> Morten Sales
>
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-- 
FARHI Emmanuel <farhi at ill.fr>
Groupe DS/CS, ILL4/156, Tel (33) 4 76 20 71 35
ILL, Grenoble