[math] Using the hessian in scalar unconstrained optimization

[Ajo Fod]

Hello,

Is'nt there an advantage to being able to compute the Jacobian of the
gradient precisely at a point?

If so, is there a class that uses the Jacobian instead of estimating the
jacobian from the last few iteration as NonLinearConjugateGradientOptimizer
does?

Thanks,
-Ajo