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MathGroup Archive 2005

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Re: global fit

  • To: mathgroup at smc.vnet.net
  • Subject: [mg57496] Re: global fit
  • From: "Pascal" <Pascal.Plaza at ens.fr>
  • Date: Sun, 29 May 2005 21:00:14 -0400 (EDT)
  • References: <d79dra$l1l$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

I should probably have mentioned the form of that function I wish to
find the minimum of:

g[a_, b_, c_, d_] := (
    A = {Table[f1[n, a, c, d], {n, 1, 60}], Table[f2[n, b, c, d], {n,
1, 60}],
           Table[f3[n, c, d], {n, 1, 60}], Table[f4[n, c, d], {n, 1,
60}],
           Table[1, {n, 1, 60}]};
    invA = PseudoInverse[A];
    X = A.invA;
    residue = B - X.A;
    Norm[Flatten[residue]]
    )

This function is certainly a bit slow but it does work. I could check
with ContourPlot the existence of a minimum along a and b (c and d
being fixed).

I tried FindMinimum just on g[a,b0,c0,d0] with b, c and d fixed and
giving a very good starting point and limits for a but it also failed.


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