Re: Re: Fit with constraints?

*To*: mathgroup at smc.vnet.net*Subject*: [mg23330] Re: [mg23316] Re: Fit with constraints?*From*: "Martin Rommel" <Martin_Rommel at mac.com>*Date*: Tue, 2 May 2000 00:43:12 -0400 (EDT)*References*: <200005012346.SAA27800@southpark.wolfram.com>*Sender*: owner-wri-mathgroup at wolfram.com

With hindsight it's obvious. Thanks for the tip. It should be in the book maybe. I always knew that the Mathematica book is too brief. Martin ----- Original Message ----- From: David Withoff <withoff at wolfram.com> To: mathgroup at smc.vnet.net Subject: [mg23330] Re: [mg23316] Re: Fit with constraints? > Martin Rommel <Martin_Rommel at mac.com> wrote in message > news:8eg5ee$giq at smc.vnet.net... > > It seems the Fit function lacks the option to fix a point (like "set > > intercept" in Excel). > > > > How is that best done? > > > > Martin > > Fixing a point or setting an intercept just means using a model > that always passes through a particular point, as in > > In[1]:= Fit[{{1,2},{3,7},{4,6},{7,9},{11,14}}, x-4, x] > > Out[1]= 1.64706 (-4 + x) > > which fits the data to a straight line that passes through 4 (that is, > it sets the y intercept to 4). If you have an example where you're > not sure how to do this, you could try posting your example, or > contacting technical support. In any case, fixing a point is just > a simple modification of the model in the input to Fit. > > Dave Withoff > Wolfram Research