[Bonmin] starting point

[Stefan Vigerske]

Hi,

> It depends what you mean by a starting point. The branch-and-cut in 
> Bonmin does not use a starting point (it is an implicit enumeration 
> algorithm) so there is no way to specify one. The only thing which can 
> be used by Bonmin is a good cutoff value to help prune nodes in the tree.
> 
> Now the nonlinear programming solver used by Bonmin to solve continuous 
> relaxations is an interior point method and can use a starting point to 
> improve convergence. You can specify such a starting point in the ampl 
> model when you declare your variables. This starting point will be used 
> to solve the root node relaxation.

I think she would like to have Bonmin consider this point also for a 
first incumbent solution, i.e., if you provide Bonmin with an integer 
and NLP-feasible solution, it should make use of it. Like the mipstart 
option in CPLEX or CbcModel::setBestSolution(), 
http://www.coin-or.org/Doxygen/Cbc/class_cbc_model.html#9192ca20d686cc817dcac8500bf3837c

Stefan

-- 
Stefan Vigerske
Humboldt University Berlin, Numerical Mathematics
http://www.math.hu-berlin.de/~stefan