random sampling of rows
in [Matlab]
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From: ravi on 22 Jun 2010 20:00 Hi guys, I have the following matrix: X = [ 1 2 3; 4 5 6; 7 8 9] In matlab it looks like this: >> X = [ 1 2 3; 4 5 6; 7 8 9] X = 1 2 3 4 5 6 7 8 9 However, if I want to get X to output with randomly sampled rows for example,: X = 4 5 6 1 2 3 7 8 9 OR X = 7 8 9 4 5 6 1 2 3 and so forth for all different possible combinations , what can i do? Thanks Ravi
From: Wayne King on 22 Jun 2010 20:20 "ravi " <ravi_071(a)hotmail.com> wrote in message <hvriqn$h5g$1(a)fred.mathworks.com>... > Hi guys, > > > I have the following matrix: > > X = [ 1 2 3; 4 5 6; 7 8 9] > > In matlab it looks like this: > >> X = [ 1 2 3; 4 5 6; 7 8 9] > > X = > > 1 2 3 > 4 5 6 > 7 8 9 > > However, if I want to get X to output with randomly sampled rows for example,: > > X = > > 4 5 6 > 1 2 3 > 7 8 9 > > OR > > X = > > 7 8 9 > 4 5 6 > 1 2 3 > > and so forth for all different possible combinations , what can i do? > > > Thanks > Ravi > Hi Ravi, Do you just want randomly-selected permuations? or are you really looking for all possibilities? I wasn't sure from your post. If you want to get random permutations: X = [ 1 2 3; 4 5 6; 7 8 9]; Indices = randperm(size(X,1)); X(Indices,:) Wayne
From: Matt Fig on 22 Jun 2010 20:21 x(randperm(size(x,1)),:)
From: ravi on 22 Jun 2010 20:29 hi wayne, i'm looking for all possibilities. thanks for your help ravi
From: Matt Fig on 22 Jun 2010 21:28
% Sample data x = reshape(randperm(8),4,2); % One of many approaches to the problem: Store result in a cell array. D = size(x,1); D = mat2cell(perms(1:D),ones(prod(1:D),1),D); D = cellfun(@(t) x(t,:),D,'Un',0) |