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Re: naive question

  • To: mathgroup at
  • Subject: [mg92844] Re: [mg92781] naive question
  • From: Francisco Gutierrez <fgutiers2002 at>
  • Date: Tue, 14 Oct 2008 05:01:43 -0400 (EDT)
  • Reply-to: fgutiers2002 at

Many thanks to Bob and Valerie for their fast and ultraeffective responses.

--- On Mon, 10/13/08, Bob Hanlon <hanlonr at> wrote:

From: Bob Hanlon <hanlonr at>
Subject: [mg92844] Re: [mg92781] naive question
To: fgutiers2002 at, mathgroup at
Date: Monday, October 13, 2008, 6:26 AM

expr = Fit[{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}, {1, x1, x2}, {x1, x2}];

Flatten[CoefficientList[expr, {x2, x1}]] // Most


Most is used to drop the coefficient (0) of the (x1*x2) term 

Cases[expr, _?NumericQ, Infinity]


Or using FindFit rather than Fit

{a, b, c} /. 
 FindFit[{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}, 
  a + b*x1 + c*x2, {a, b, c}, {x1, x2}]


Bob Hanlon

---- Francisco Gutierrez <fgutiers2002 at> wrote: 

Dear Friends:
I am using Fit within a function, and I want it to produce only a list of
 coefficients, without the variables.
For example, if I plug into fit the following:
Mathematica produces:
1.55556+0.555556 x1+0.444444 x2
I want to get only the following list:
It seem awfully simple, but I haven't managed.
How can I do it?


Bob Hanlon

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