[Ipopt] nele_hess

Andreas Waechter andreasw at watson.ibm.com
Wed Mar 5 08:44:35 EST 2008

Hi Ned,

> If I use
> 	AddIpoptStrOption( ipopt_problem, "hessian_approximation", "limited-
> memory" );
> do I have to give the number of nonzeros in the Hessian, that is, do
> I have to set nele_hess?
> The function evaluation the Hessian returns false in this case.

If you set this option, you don't need to set the nnz_h_lag variable of 
the TNLP::get_nlp_info method, since this variable will not be looked at 
in this case.  Also, with this option, TNLP::the eval_h method is never 
going to be called.



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