MathGroup Archive 2002

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Question on FindMinimum

  • To: mathgroup at
  • Subject: [mg33415] Question on FindMinimum
  • From: "Coleman, Mark" <mark.coleman at>
  • Date: Wed, 20 Mar 2002 01:53:36 -0500 (EST)
  • Sender: owner-wri-mathgroup at


I am using the built-in FindMinimum command to minimize a fairly complex 
function (of two variables, b1 and b2). When I apply FindMinimum, just 
using the default method and without specifying an explicit gradient, 
the command produces approximately the correct result. When I next 
attempt to specify the Method->Newton (or QuasiNewton), I get an error 
message: [contact the author to get the message - moderator]


I took this message to mean that Mathematica could not symbolically compute the 
derivative automatically. I then calculated the gradient function and 
used the Gradient-> option directly. When the Method->Automatic, the 
correct result is returned. When the Method->Newton (or QuasiNewton) the 
same error message appears. Note that both the objective function and 
the gradient do have real values at {b1,b2} = {0.,1.}

Any ideas?



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