All possible subsets of a given set MATLAB答案

【问题标题】：All possible subsets of a given set MATLABAll possible subsets of a given set MATLAB
【发布时间】：2022-12-01 22:27:30
【问题描述】：

Hello I am trying to write a function in Matlab that takes a whole set and outputs all possible subsets of a given set.

For example: If I have a set

A = {1,2}

All possible subsets are

B = { {}, {1}, {2}, {1,2} }

I have tried nchoosek

Any ideas? Kinda lost on how I should implement this?

【问题讨论】：

Why do you need all possible sets? Obtaining all those is either trivial or impossible. Trivial in case of a few elements, like you have, impossible for more than (roughly) 12 elements, given it grows factorially. You cannot possibly process all of those, let alone store in your RAM.

标签： matlab

【解决方案1】：

Given set S with n elements, there are 2^n subsets, including the empty set {}. The function nchoosek is the appropriate way to perform this operation. You can try the script below. It does not display the empty set.

set = [1,2,3,4,5]

for i=1:length(set):
    disp(nchosek(set, i))

【讨论】：

OP already mentions nchoosek. Plus, as I said in my comment and you mention here: this will create a ridiculously large number of sets very quickly, thus it's infeasible for all but the trivially small sets.
It is computationally possible, although your judgment ridicules the effort. I find it very unpleasing.
It's computationally possible for n very small (the docs suggest up to n=10). As soon as n=30 you'll need more computational power than available in the biggest clusters.
Great. It seems a great application for generators of low cardinality.