In the ODE-file of the object to be continued, you can provide the derivates that are needed for the continuation algorithm or other computations. The continuer has stored the handle to the derivatives in the variables
cds.curve_jacobian, cds.curve_hessians.If
cds.symjac= 1,
then a call to feval(cds.curve jacobian,
x) must return the (n
−1)
×
n
Jacobian matrix evaluated at point
x.
If cds.symhess= 1,
then a call to feval(cds.curve hessians,
x) must
return a 3-dimensional (n
− 1
×
n
×
n)
matrix H
such that
H(i,
j, k) = [(¶2Fi(x))/(¶xj¶xk)].
In the present implementation in most cases cds.symhess= 0, so the ODE-file does not provide second order derivatives, since they are not needed in the algorithms used.