Path: news.mathworks.com!not-for-mail From: "salman " <salmanabdullah9@gmail.com> Newsgroups: comp.soft-sys.matlab Subject: Re: Error using times, Matrix dimensions must agree Date: Tue, 17 May 2011 05:39:02 +0000 (UTC) Organization: The MathWorks, Inc. Lines: 50 Message-ID: <iqt1lm$7pi$1@newscl01ah.mathworks.com> References: <iqsrio$kfj$1@newscl01ah.mathworks.com> <iqssvn$ob1$1@newscl01ah.mathworks.com> Reply-To: "salman " <salmanabdullah9@gmail.com> NNTP-Posting-Host: www-00-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: newscl01ah.mathworks.com 1305610742 7986 172.30.248.45 (17 May 2011 05:39:02 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Tue, 17 May 2011 05:39:02 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 2784299 Xref: news.mathworks.com comp.soft-sys.matlab:727176 "Roger Stafford" wrote in message <iqssvn$ob1$1@newscl01ah.mathworks.com>... > "salman " <salmanabdullah9@gmail.com> wrote in message <iqsrio$kfj$1@newscl01ah.mathworks.com>... > > > > Dear friends, > > > > Have a good day, > > > > i am getting this message "Error using times, MD must agree", > > here are my three lines of code; > > > > t=linspace(0,.0000001,200) > > z=linspace(-.0002,.0002,200); > > Initial_value=(exp(-(z.^2)./L.^2).*cos(z))./z; > > E_1=vee_1*(Y(:,3).*t)+initial_value.*(z- vee_1*t);%------this is where the error comes > > > > Y(:,3) is of size 200x1; > > > > > > i dont know why this error comes, as i have checked the syntax and logic, it seems correct to me, yet its giving this error. > > > > your help is greatly appreciated. > > > > thanks alot > - - - - - - - - > The multiplication in "(Y(:,3).*t)" is invalid since Y(:,3) is a column vector and t is a row vector. They must be the same size to use ".*". Also you should make sure that "vee_1" is a scalar or you will have other troubles. > > Roger Stafford Dear Roger, if i change the above equation and replace Y(:,3) by [Y(:,3)]', so now this becomes and row vector. after this however, the previous error is gone, but now i want to create the mesh from t and z and then get surface plot for E(z,t). but it says Warning: Matrix dimensions must agree, not rendering mesh. i used this one; E_1=vee_1*((Y(:,3))'.*t)+Initial_value.*(z- t); meshgrid(t,z); surf(t,z,E_1) where; size(z)=1 200 size(t)=1 200 size(Y(:,3)')=1 200 size(Initial_value)=1 200, i will be grateful for help. thanks