numgradient and numhessian can be used for numeric
differentiation. numgradient returns the derivative of an
vector-valued function with respect to a
vector
in a
matrix. numhessian returns the derivative
of a real-valued function with respect to a
vector in
a
matrix. Both functions are quite accurate. numderivatives.m,
which follows, shows how it can be done.
/home/sh/Dokumenter/octave/octave-forge/main/optim/doc/numderivatives.m
The results are:
/home/sh/Dokumenter/octave/octave-forge/main/optim/doc/numderivative.out