I want to implement all possible 2*2 or 3*3 or n*n matrices by using 0 or/and 1 as their elements.
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I want to implement all possible 2*2 or 3*3 or n*n matrices by using 0 or/and 1 as their elements.
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Jan
on 25 Feb 2022
Edited: Jan
on 26 Feb 2022
n = 3;
M = rem(uint8(floor((0:2^(n*n)-1) .* pow2(0:-1:1-n^2).')), 2);
M = reshape(M, n, n, []);
M(:, :, 1)
M(:, :, 2)
M(:, :, 512)
This is growing extremely fast. After n=7 2^(n*n) leave the range of accurate integer values. For n=6 you need 550 GB RAM. Unfortunately I do not find a way to create this array directly as UINT8 in pure Matlab. Otherwise 69 GB RAM would be sufficient for n=6.
For standard computers, the function is bearable for n=1 to 5 only. It does not seem to be worth to write a C-Mex function for this job.
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Jan
on 25 Feb 2022
% s = char(ones(numel(d),numBits)*48);
Intermediately a double array is created before it is converted to char. What a pity.
Worth to send an enhancement request to MathWorks.
Did you take a look into the code to extract the bits of the uint64 values in dec2bin?
It would be smart, if we can use bitget with implicit expanding and replying uint8 instead of doubles:
bitget((0:2^(n*n)-1).', 1:n, 'uint8') % Not working!!!
Bruno Luong
on 25 Feb 2022
No I did not look at the code dec2bin.
After taking a look fromm your attention, yeah the implementation seems not particularly cheap in term of memory and speed.
More Answers (1)
Benjamin Thompson
on 25 Feb 2022
Looks like 16 combinations of 4 values for the 2x2, and 2^9 combinations of 9 values for the 3x3. Try using dec2bin and reshape in a for loop, and post code and specific questions if you run into problems.
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