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Re: multimin question
Fabrice Rossi writes:
> 1) it is not able to find a x>e (e is the machine precision) such
> that f(x)<f(0) 2) it has x such that x>e, f(x)<f(0) but it is not
> able to find a y>x such that f(y)>f(x).
> The second case is quite strange. The first case is very common
> and simply shows that the descent direction does not allow
> decrease. I considered this to be a bug, so I programmed bracketing
> to return GSL_FAILURE. But it should return something else. Then in
> the multimin algorithm, we will react on the result. If the
> bracketing fails for reason 1 and we have used the gradient as
> descent direction, we might decide that the algorithm as converged.
> Comments?
If you need to introduce an extra error code to distinguish various
cases, and it can be done in a natural way, then feel free to do that.
It is part of the library philosophy to give every distinct type of
error its own error code.