How can I create a random matrix without repeating any value between column

I get two columns with the same value when I generate the matrix. For example,
1 1 3 2 4
4 4 1 4 3
2 2 2 3 1
3 3 4 1 2
I want to get something like the 10 combinations from the 24 combinations(4 factorial).
1 1 3 2 4 1 2 4 3 2
2 4 1 4 3 3 3 1 2 1
3 2 2 3 1 4 1 3 4 3
4 3 4 1 2 2 4 2 1 4
I need the matrix to form the chromosomes for GA.

3 个评论

It is not at all clear to me how you obtained the second of those matrices from the first. Some of the columns (like columns 2, 3, 4, and 5) are copies of columns from the first matrix, but some (like columns 1 and 6) are not. What rules specifically do you need to follow in generating that second matrix from the first?
As Steven mentions, it's not clear what is the pattern you are following to obtain the output.
From a cursory glance, it can be observed from the output that the 1st column is sorted and the 6th column corresponds to the indices of the sorted values of the 1st column. But the it's not clear what's the logic behind the columns 7-10.
Sorry for not making my question clear. There are no special rules to follow. So long as the matrix generates non-repeated combinations from the 24 combinations, then it is good enough. It does not need to be exactly like the second matrix. The second matrix is just an example.

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 采纳的回答

Hello Wan,
all columns contain 1 through 4, and all columns are different
a = perms(1:4) % all 24 permutations of 1:4
ind = randperm(24);
ind = ind(1:10) % an index of 10 random integers from 1 to 24, no repeats
b = a(ind,:)' % 10 random choices from the rows of a,
% then transpose to get 4x10 matrix

1 个评论

Wow, it works very well. Thanks a lot, David. I really appreciate it and there are explanations.

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更多回答(1 个)

You can use reshape(), randperm(), numel(), size() fcns to create ramdom swaps of the already existing matrix elements:
A1 = [1 1 3 2 4;
4 4 1 4 3;
2 2 2 3 1;
3 3 4 1 2];
A_new = [reshape(A1(randperm(numel(A1))), size(A1)), reshape(A1(randperm(numel(A1))), size(A1))]
A_new = 4×10
3 4 4 3 2 2 2 3 4 2 1 3 4 2 1 1 1 2 1 4 3 4 4 1 2 1 4 4 3 3 1 3 2 1 2 3 3 4 1 2

2 个评论

@Sulaymon Eshkabilov, every column must contain all the numbers [1 2 3 4]. The output from your code does not.
Ya, I need every column to contain 1,2,3,4 like what @Dyuman Joshi mentions.

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