"plus/minus" sign operator

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frwmetric
frwmetric on 17 May 2013
Hi
I have a row matrix which is like n=[x,y,z] I need to consider plus and minus signs at the same time and get a permutations of them. In conclusion I need that solutions
n=[x,y,z]
n=[-x,y,z]
n=[x,-y,z]
n=[x,y,-z]
n=[-x,-y,z]
n=[-x,y,-z]
n=[x,-y,-z]
n=[-x,-y,-z]

Accepted Answer

Iain
Iain on 17 May 2013
It depends what you want to do with it.
M = [1 1 1; 1 1 -1; 1 -1 1; 1 -1 -1; -1 1 1; -1 1 -1; -1 -1 1; -1 -1 -1];
Out = (M * Row')' ;
Each row of Out is what you want.
You might want to programatically generate M if you have more columns on your row.
  2 Comments
Iman Ansari
Iman Ansari on 17 May 2013
[a b c]=meshgrid([-1 1]);
M=[a(:) b(:) c(:)];
frwmetric
frwmetric on 17 May 2013
thank you...

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More Answers (1)

C.J. Harris
C.J. Harris on 17 May 2013
Not exactly elegant, but it works:
A = [1 2 3];
B = (dec2bin(0:2^length(A)-1) - '0');
C = sum(B .* repmat(A, 2^length(A), 1), length(A)) + sum(~B .* repmat(-A, 2^length(A), 1), length(A));

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