matlab sorting rows by one column
>> A = [1,1,1;0,0,0;2,2,2]
A =
     1     1     1
     0     0     0
     2     2     2
>> [~,idx] = sort(A(:,1))
idx =
     2
     1
     3
>> A = A(idx,:)
A =
     0     0     0
     1     1     1
     2     2     2
>>