MATLAB: Rotate vector in row

2-optdepotsrotate

Hi, i have an array
n= [1,19,15,18,21,10,16,2,7,3,17,6,1;
1,14,20,8,4,13,9,5,1,0,0,0,0;
1,11,12,1,0,0,0,0,0,0,0,0,0];
What i need to do is to randomly choose 2 elements of each row (but not the ones and the zeros) and rotate the vector in between them .
For example new_n= [ 1,19,15,17,3,7,2,16,10,21,18,6,1;
1,14,13,4,8,20,9,5,1,0,0,0,0;
1,12,11,1,0,0,0,0,0,0,0,0,0]
If it is possible i would like to be able to do it for any array i might have. (the thing is that 1-etc-1 in each row are non equal paths that start at depot 1 and end at it after they go through the other nodes, so i want the rearrangement to happen between the depots)

Best Answer

This may solve your problem:
rng(42)
n=   [1,19,15,18,21,10,16,2,7,3,17,6,1;
        1,14,20,8,4,13,9,5,1,0,0,0,0;
        1,11,12,1,0,0,0,0,0,0,0,0,0];
nrev = n;
for idx=1:size(n,1)
    
    % Get the position of the initial 0
    Ncolums = find(n(idx,:)==0);
    if isempty(Ncolums)
        Ncolums = size(n,2);
    else
        Ncolums = Ncolums(1)-1;
    end
    Ncolums = Ncolums-2; % Remove first and last 1
    % Get a random index permutation between valid index
    Index = randperm(Ncolums)+1; % Add offset so it starts by two
    Index = sort(Index(1:2));
    
    % Invert row
    nrev(idx,Index(1):Index(2)) = n(idx,Index(2):-1:Index(1));
 
end
nrev
nrev =
     1    19    15    18    21    10    16     6    17     3     7     2     1
     1    14    20     8    13     4     9     5     1     0     0     0     0
     1    12    11     1     0     0     0     0     0     0     0     0     0
Related Question