what is the single command?????????
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I want to create matrix size is 100*12. Each row contain only 5 zeros other elements are 1. for ex
A=[1 1 1 0 0 1 1 0 0 0 1 1 ;
0 0 1 1 0 0 1 1 0 1 1 1;]
Note: Nobody row is repeated
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Stephen23
le 17 Août 2018
Modifié(e) : Stephen23
le 17 Août 2018
R = 100; % rows
C = 12; % columns
N = 5; % number of 1's.
cmb = nchoosek(1:C,N); % all unique column combinations.
idx = randperm(size(cmb,1)); % indices to randomize combinations.
idc = cmb(idx(1:R),:); % (col index) pick first 100 random combinations.
idr = ndgrid(1:R,1:N); % (row index).
mat = ones(R,C); % preallocate output matrix.
mat(sub2ind([R,C],idr,idc)) = 0
Check:
>> all(sum(mat,2)==7) % all rows sum to seven.
ans = 1
>> all(ismember(mat(:),0:1)) % only 0's and 1's.
ans = 1
>> size(unique(mat,'rows')) % all rows are unique.
ans =
100 12
4 commentaires
Stephen23
le 17 Août 2018
@VIJAY: I hope that it helps. Remember to accept the answer. Accepting my answer is the easiest way to thank me.
Plus de réponses (1)
Rik
le 17 Août 2018
First generate all combinations, and then select 100 from them:
total_row_length=12;
number_of_zeros=5;
selected_number_of_rows=100;
v=1:total_row_length;
col_positions = nchoosek(v,number_of_zeros);
row_positions=repmat((1:size(col_positions,1))',1,size(col_positions,2));
out=ones(size(col_positions,1),total_row_length);
inds=sub2ind(size(out),row_positions,col_positions);
out(inds)=0;
%select a random sample from all possible rows
selected_rows=randperm(size(out,1),selected_number_of_rows);
result=out(selected_rows,:);
2 commentaires
Stephen23
le 17 Août 2018
Modifié(e) : Stephen23
le 17 Août 2018
@Star Strider: can you please give explanations for your votes, rather than just disappearing without comment. I am interested to know what you found in Rik Wisselink's answer, that you felt was missing in mine (they are almost identical). Many thanks!
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