If cds.symjac, then a call to feval(cds.curve_jacobian, x) must
return the
Jacobian matrix evaluated at point
.
If cds.symhess, then a call to feval(cds.curve_hessians, x) must
return a 3-dimensional (
) matrix
such that
.
In the present implementation in most cases cds.symhess, so the ODE-file does not provide second order derivatives, since they are not needed in the algorithms used.