<div><font color="#000099">Dear all,</font></div>
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<div><font color="#000099">I use IPOPT in a PDE constrained optimization problem (distributed parameter identification), i like to use second order information instead of hessian approximation, but direct construction of Hessian is very expensive,
e.g. for 10^5 design variable, we should solve 10^5 additional PDE ! but computation of Hessian vector product is cheap, needs only solution of two additional PDE.</font></div>
<div><font color="#000099"></font> </div>
<div><font color="#000099">I would like to know that how is difficulty of implementation of this issue in IPOPT and what portion of code should be modified?</font></div>
<div><font color="#000099"></font> </div>
<div><font color="#000099">Also, is this issue in plan of developers (i think it considerably increase capability and range of application of IPOPT)?</font></div>
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<div><font color="#000099">Thanks.</font></div>
<div><br><font color="#000099">Best Regards,</font></div>
<div><font color="#000099">RT.</font></div>