MATLAB: RANDOM FLIPPING FROM 1 TO -1

random flipping from 1 to -1

Hi to all the users, I have tried a code in which numbers are changed from 1 to -1 turn by turn. But I need some condition.
  1. All elements are 1
  2. A random element of matrix is selected and changed from 1 to -1.
  3. The process goes till all the elements are changed from 1 to -1 randomly.
  4. Once the change happens it should be fixed. ie once 1 is changed to -1 it should remain fixed.
Hope i have cleared my idea…..
Regards
clc
clear all
format compact
nrows = 3
A = ones(nrows)
E_A = sum(sum(A))
n = numel(A);
for k=1:n
  A(k) = -1
  E_B = sum(sum(A))    
end

Best Answer

Make this change:
    :
  p = randperm(n);  % <-- Add this line just before for-loop
  for k=1:n
  A(p(k)) = -1;  % <-- change the index from k to p(k)
    :
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