Path: news.mathworks.com!not-for-mail From: "qi li" <liqi3837671@hotmail.com> Newsgroups: comp.soft-sys.matlab Subject: solving equation of multiple exponent terms summation with variable 'z' Date: Sun, 4 Mar 2012 11:59:15 +0000 (UTC) Organization: The MathWorks, Inc. Lines: 10 Message-ID: <jivlej$sg2$1@newscl01ah.mathworks.com> Reply-To: "qi li" <liqi3837671@hotmail.com> NNTP-Posting-Host: www-04-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: newscl01ah.mathworks.com 1330862355 29186 172.30.248.35 (4 Mar 2012 11:59:15 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Sun, 4 Mar 2012 11:59:15 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1732016 Xref: news.mathworks.com comp.soft-sys.matlab:759786 Hi everyone, I have a problem and I cann't figure it out. the origin is from tempting to plot a 3-d deformation sphere in SVM, it needs solve sigma(K(x,ai))=1 where K is gaussian kernel trick,which means K(x,ai)=exp(||ai-x||^2/(-2)),ai is 3 components vector,when i=1,2,3 a(:,1)=[1;1;1] a(:,2)=[2;2;2] a(:,3)=[3;3;3], x is [1;1;z] vector,z is varable ,so equation becomes for i=1:3 s=s+exp(((1-a(1,i))^2+(1-a(2,i))^2+(z-a(3,i))^2)/(-2)) end then next equation s-1=0 shoulde be figured out with 'z', who has the idea how to solve it? I found using fzero() may works,but if I have no idea about the initial value(I want all possible results of the equation) and in fact there may be hundreds of equations need to be solved(I make some simplications!). can someone help me? thanks advance