From a matrix, Pick one element from each row and not from same column for all possibilities. Only for non zero elements.
1 次查看(过去 30 天)
显示 更早的评论
Hi, From a matrix, I would like to pick one element from each row and not from same column for all possibilities.
Only for non zero elements.
Example, from A = [1 2 0; 1 2 0; 0 0 3], I want to obtain (1 2 3 and 2 1 3).
Thank you
0 个评论
采纳的回答
Puru Kathuria
2020-7-22
Hi,
Your requirements are answered in a similar question mentioned in this link. Also, selecting set of elements from a matrix such that each element comes from distinct row and column can also be modeled as a Matching problem. (graph theory)
更多回答(1 个)
Bruno Luong
2020-7-23
编辑:Bruno Luong
2020-7-23
A dynamic programming for fun
function p = nzperm(A,c)
if nargin < 2
c = 1;
end
r = find(A(:,c));
if isempty(r)
p = [];
elseif c==size(A,2)
p = A(r,c); % p = r(:);
else
p = [];
for i=r.'
Ai = A;
Ai(i,:) = 0;
q = nzperm(Ai,c+1);
a = A(i,c); % a = i
q = [a+zeros(size(q,1),1) q];
p = [p; q]; %#ok
end
end
Result
>> A=rand(5); A = A.*(rand(size(A))>0.6)
A =
0 0.6468 0.7881 0.5598 0.8008
0.5607 0 0 0 0.8961
0 0 0 0.9394 0.5975
0 0.4756 0.1335 0 0
0 0.3625 0.0216 0 0.9437
>> nzperm(A)
ans =
0.5607 0.6468 0.1335 0.9394 0.9437
0.5607 0.4756 0.7881 0.9394 0.9437
0.5607 0.4756 0.0216 0.5598 0.5975
0.5607 0.4756 0.0216 0.9394 0.8008
0.5607 0.3625 0.1335 0.5598 0.5975
0.5607 0.3625 0.1335 0.9394 0.8008
Note: this code will be slow on large array, since MATLAB make copies of matrix at every step. This algorithm could be implemented without copy using C mex.
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Characters and Strings 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!