Hi Charlotte, You'll need to set the maximum parameter to TRUE by doing maximum=TRUE when calling optim() Clarence From: gov2001-l-bounces at lists.fas.harvard.edu [mailto:gov2001-l-bounces at lists.fas.harvard.edu] On Behalf Of charlotte cavaille Sent: Wednesday, February 25, 2009 1:13 AM To: gov2001-l at lists.fas.harvard.edu Subject: Re: [gov2001-l] what is BFGS doing? Thanks Patrick...as you can guess though my question comes from the fact that it seems for me that optim() can just never return the maximum of the objective function whatever starting values I input....i thought that understanding what BFGS was doing might have helped ...unfortunately it didn't ! 2009/2/25 Patrick Lam <plam at fas.harvard.edu<mailto:plam at fas.harvard.edu>> i wouldn't worry too much about the exact details of BFGS or any of the canned optimization methods. BFGS is actually more like the Newton-Rhapson method, in which we only start with one initial guess and then build our way there with gradients. On Wed, Feb 25, 2009 at 1:04 AM, charlotte cavaille <charlotte.cavaille at gmail.com<mailto:charlotte.cavaille at gmail.com>> wrote: it is 1 am so maybe it is just my brain but: how can we have an iteration process with BFGS (equivalent to the bisection one in principle) if we start with one point and not with a surface? thanks! charlotte 2009/2/24 Johnathan Boysielal <boysiel at fas.harvard.edu<mailto:boysiel at fas.harvard.edu>> Dear class, As it turns out, I still need a co-author for the final paper. I am a G3 in the Political Economy & Government program (Kennedy School), broadly interested in international and comparative political economy. If you are still looking for a co-author and are interested in topics along these or similar lines, please send me an email. I have provisionally selected some papers on the very timely topic of political intervention in the financial markets, but of course there is no shortage of interesting papers in the world.. - Johnathan _______________________________________________ gov2001-l mailing list gov2001-l at lists.fas.harvard.edu<mailto:gov2001-l at lists.fas.harvard.edu> http://lists.fas.harvard.edu/mailman/listinfo/gov2001-l _______________________________________________ gov2001-l mailing list gov2001-l at lists.fas.harvard.edu<mailto:gov2001-l at lists.fas.harvard.edu> http://lists.fas.harvard.edu/mailman/listinfo/gov2001-l -- Patrick Lam Department of Government and Institute for Quantitative Social Science, Harvard University http://www.people.fas.harvard.edu/~plam<http://www.people.fas.harvard.ed… _______________________________________________ gov2001-l mailing list gov2001-l at lists.fas.harvard.edu<mailto:gov2001-l at lists.fas.harvard.edu> http://lists.fas.harvard.edu/mailman/listinfo/gov2001-l