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Homework Help: Matlab - Normal equation for linear least squares model fitting

  1. Apr 6, 2012 #1
    1. The problem statement, all variables and given/known data

    Im trying to construct a function in matlab that models linear least squares model fitting through the use of normal equations.



    2. Relevant equations

    Normal equation

    (A'*A*c)=(A'*y)

    A= [column vector of all x ; column vector of all 1]
    y= [column vector of all y]
    c = [b;a] where a&b are coefficients of the best fit line

    3. The attempt at a solution


    function c=mregress(x,y)
    A=[x 1]
    B=[y]

    c=(A'*A)\(A'*B);

    Error in ==> mregress at 2
    A=[x 1]


    I am very new to matlab and dont know much about it.
    I think the problem is representing x a column vector and 1 is also a column vector of 1.

    How do I represent this?
     
  2. jcsd
  3. Apr 6, 2012 #2
    A=[x,ones(n,1)] where n is the number of elements in x.
     
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