Re: Concurrent Curve Fitting...

*To*: mathgroup at smc.vnet.net*Subject*: [mg18577] Re: [mg18562] Concurrent Curve Fitting...*From*: Ken Levasseur <Kenneth_Levasseur at uml.edu>*Date*: Tue, 13 Jul 1999 01:01:19 -0400*Organization*: UMass Lowell Mathematical Sciences*References*: <199907100618.CAA03020@smc.vnet.net.>*Sender*: owner-wri-mathgroup at wolfram.com

Robert: You say the {xm,ym} are specific to the data set, but are they know or are you free to select them? If they are known, then this appears to be a fairly routine "mixed approximation" problem. I did a little bit of research in this area in my disertation (several years before Mathematica) and I think that there may be some known algorithms to solve the problem. You might want to check the Journal of Approximation Theory for references. If the {xm,ym} are not fixed, it seems like an interesting (and more difficult problem) Ken Levasseur Math. Sci. UMass Lowell Robert Carneim wrote: > > Can anyone help me? > > Here's what I want to do: > > I have two sets of data which are related in such a way that, when plotted, > they should have the same shape (or I want to force the curve fits to have > the same shape), but at a different location. > So, for example (and simplicity} suppose I have two sets of data which can > be fit by lines, y=mx+b. I want to fit data set 1 to (y-y1)=m(x-x1)+b, and > data set 2 to (y-y2)=m(x-x2)+b, where m and b are common and xn and yn are > specific to the data set. > This is a fairly easy to do indirectly, even by hand, but is there a way to > get Mathematica to do this directly, i.e., finding the two curve fits > concurrently? Obviously, I'm trying to do this for much more complex models. > > Any input would be appreciated. > > Thanks, > -rdc.

**References**:**Concurrent Curve Fitting...***From:*"Robert Carneim" <rdc120@psu.edu>