generating a matrix with all possibilities in matlab

Question

is there a simple command to do this:

i found this http://www.mathworks.co.kr/matlabcentral/fileexchange/7147-combn--4-3- but this isn't yet a thing in matlab

tried M = combn([0 1],3) bo i got Undefined function 'combn' for input arguments of type 'double'. in return

score 2 · Answer 1 · answered Apr 29 '14 at 20:42

You're looking for matlab's perms() function.

v0=[0 0 0]; 
v1=[1 0 0];
v2=[1 1 0];
v3=[1 1 1]; 
p1=perms(v1);
p2=perms(v2);
combs = cat(1,v0,p1,p2,v3);

This of course gives all permutations meaning that order matters (even for the zeros) so to get only the unique combinations you could then use:

combs=unique(combs,'rows');

Which gives:

combs =
     0     0     0
     0     0     1
     0     1     0
     0     1     1
     1     0     0
     1     0     1
     1     1     0
     1     1     1

As a side note if you downloaded the file from the file exchange make sure it is on your matlab path, or in your current directory and this will avoid the unknown function error. You can read about how matlab's path works here

Why was this downvoted? Please comment on how I can improve the answer. — Raab70, Apr 30 '14 at 13:53

score 2 · Accepted Answer · edited May 23 '17 at 11:46

2

An easy approach is to generate all numbers from 0 to 2^n-1, where n is the number of rows, and convert them into binary:

n = 3;
result = dec2bin(0:2^n-1)-'0';

Or particularize this Q&A to your case.

edited May 23 '17 at 11:46

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answered Apr 29 '14 at 22:20

Luis Mendo

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how would i remove the eye(I) vectores(one 1 in a line) and store the rest? – jabk Apr 30 '14 at 12:00
@user2202368 Sorry, I don't understand your question – Luis Mendo Apr 30 '14 at 12:19
@LuisMendo from the matrix of all combination i would like the remove lines(1 0 0 0; 0 1 0 0; 0 0 1 0; 0 0 0 1) and save what is left – jabk Apr 30 '14 at 12:27
@user2202368 Oh I see. Use `result2 = result(sum(result,2)~=1,:);` (this keeps only rows whose sum is different than 1) – Luis Mendo Apr 30 '14 at 12:34

generating a matrix with all possibilities in matlab

2 Answers2