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From: "David Doria" <daviddoria@gmail.com>
Newsgroups: comp.soft-sys.matlab
Subject: Line search failing?
Date: Thu, 14 Aug 2008 21:33:02 +0000 (UTC)
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I am using fminunc to try to find the minimum of a function.
 I plotted the function (it is only 2d) and it seems
extremely well behaved - visually it there is without a
doubt a single local min if you start any where near the min
value (the value is at (20, 0) and there looks to be about a
5 unit radius of convergence).

However, when I run fminunc, I get:

Line search cannot find an acceptable point along the
current search direction.

The only thing I could think to check is if the gradient was
somehow 0-ish even though it didn't look like it in the
plot, but when I output the gradient at the iteration it
gives the error it is

Gradient is: 

ans =

   -1.2747
    0.4237

Does anyone know what else to check to see why line search
can't find a good point?

Thanks,

Dave