Opt.setPrecondMinObjective

Set Minimum Objective with Pre-conditioned Hessian

Refer to http://ab-initio.mit.edu/wiki/index.php/NLopt_Reference#Preconditioning_with_approximate_Hessians for information on preconditioning.

Equivalent in C API: nlopt_set_precond_min_objective

Params:

f = function pointer representing objective, must be extern(C)

pre = function pointer representing preconditioner function, must be 
			 extern(C)

f_data = additional data to pass to function (optional)