How to generate random matrix with constraints?
in [Matlab]
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From: Arkadiusz Gola on 6 Jul 2010 04:35 Hello, I want to generate random [0-1] m x n matrix where for example 70% are "1" fields and 30% are "0" fields. Do you think is it possible? What function should I use? Thank you in advance. Arek :-)
From: Peter Riddersholm on 6 Jul 2010 04:49 "Arkadiusz Gola" <a.gola(a)pollub.pl> wrote in message <i0uprs$5rr$1(a)fred.mathworks.com>... > Hello, > > I want to generate random [0-1] m x n matrix where for example 70% are "1" fields and 30% are "0" fields. Do you think is it possible? What function should I use? > Thank you in advance. > > Arek :-) This is not a very subtle way to do it, but it works: A = zeros(4,8); for i = 1:4 for j = 1:8 A(i,j) = rand; if A(i,j) > 0.3; A(i,j) = 1; else A(i,j) = 0; end end end
From: Oleg Komarov on 6 Jul 2010 06:06 "Arkadiusz Gola" <a.gola(a)pollub.pl> wrote in message <i0uprs$5rr$1(a)fred.mathworks.com>... > Hello, > > I want to generate random [0-1] m x n matrix where for example 70% are "1" fields and 30% are "0" fields. Do you think is it possible? What function should I use? > Thank you in advance. > > Arek :-) % Create the number of ones and zeros to respect the percentages A = [ones(70,1); zeros(30,1)]; % Generate a random index idx = randperm(100); % Select randomly and reshape A = reshape(A(idx),[10,10]); You can also use seqorg to retrieve a truly random idx sequence: idx = seqorg([1,100]); % on FEX You can find seqorg on: http://www.mathworks.com/matlabcentral/fileexchange/27942 You need an internet connection to use it. Oleg
From: Matt J on 6 Jul 2010 07:31 "Arkadiusz Gola" <a.gola(a)pollub.pl> wrote in message <i0uprs$5rr$1(a)fred.mathworks.com>... > Hello, > > I want to generate random [0-1] m x n matrix where for example 70% are "1" fields and 30% are "0" fields. Do you think is it possible? What function should I use? > Thank you in advance. ========== Do you mean that there should be a 70% probability of a matrix element being 1? If so, do rand(m,n)>0.3
From: Steven Lord on 6 Jul 2010 09:34
"Matt J " <mattjacREMOVE(a)THISieee.spam> wrote in message news:i0v47a$oe8$1(a)fred.mathworks.com... > "Arkadiusz Gola" <a.gola(a)pollub.pl> wrote in message > <i0uprs$5rr$1(a)fred.mathworks.com>... >> Hello, >> >> I want to generate random [0-1] m x n matrix where for example 70% are >> "1" fields and 30% are "0" fields. Do you think is it possible? What >> function should I use? >> Thank you in advance. > ========== > > Do you mean that there should be a 70% probability of a matrix element > being 1? If so, do > rand(m,n)>0.3 Or do you want 70% of the elements to be 1 and 30% to be 0? % Assuming m*n is a multiple of 100 here % You will need to tweak this code if this assumption is not valid m = 20; n = 20; v = [ones(1, 70*m*n/100), zeros(1, 30*m*n/100)]; M = reshape(v(randperm(m*n)), m, n) -- Steve Lord slord(a)mathworks.com comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ To contact Technical Support use the Contact Us link on http://www.mathworks.com |