Path: news.mathworks.com!not-for-mail From: "lovish " <lovishagarwal@gmail.com> Newsgroups: comp.soft-sys.matlab Subject: Re: Problem regarding Maximizing a function Date: Mon, 30 Mar 2009 01:18:01 +0000 (UTC) Organization: The MathWorks, Inc. Lines: 48 Message-ID: <gqp6k9$q5p$1@fred.mathworks.com> References: <gqp32v$kum$1@fred.mathworks.com> <gqp50a$i4s$1@fred.mathworks.com> Reply-To: "lovish " <lovishagarwal@gmail.com> NNTP-Posting-Host: webapp-05-blr.mathworks.com Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8bit X-Trace: fred.mathworks.com 1238375881 26809 172.30.248.35 (30 Mar 2009 01:18:01 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Mon, 30 Mar 2009 01:18:01 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1189748 Xref: news.mathworks.com comp.soft-sys.matlab:528558 I'm working with optimization toolbox using the 'fmincon' solver . The fmincon solver works to minimze a function. There's no inbuilt function to maximize a function. The problem that I'm encountering is that for instance when I need to maximize f(x)= x1 + x2 s.t x1+x2<=2 where x1 and x2>=0 I ain't able to do that. I'm setting the function as > > function f=objfun(x) > > f= x1+x2; > > f=-z; Instead of getting the values as x1=1 and x2=1 , it it displaying x1=x2=0 and f(x)=0 as it it minimizing the function. How should I modify the function or the conditions in the solver to maximize the function?? I would highly appreciate if someone could help me. Thanks and Regards, Lovish "John D'Errico" <woodchips@rochester.rr.com> wrote in message <gqp50a$i4s$1@fred.mathworks.com>... > "lovish " <lovishagarwal@gmail.com> wrote in message <gqp32v$kum$1@fred.mathworks.com>... > > Hi guys, > > > > I am having problems with maximizing a function using optimization tool. I have to maximize > > > > max f(x)= log (x1) + log (x2) + log (x3) > > > > with the constraints that x1+x2 <=1 ; x1+x3<=1 > > > > I'm solving it using optimization tool box using fmin solver. The function I have created is > > There is no solver called fmin in the optimization > toolbox. So it will be difficult to help you. > > > > > > function f=objfun(x) > > f= log(x1)+log(x2)+ log (x3); > > f=-z; > > > > I have used f=-z in order to maximize the function as fmin minimizes the function f(x) But it isn't working. Please guide me as to how should I use the toolbox in order to maximize the function. > > > > What is not working? What is wrong? What has > failed? In what way did it fail? > > The crystal ball is cloudy. > > John