RANDOM FLIPPING FROM 1 TO -1

Question

Offroad Jeep 2016-5-24

编辑： Walter Roberson 2016-5-25

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.

All elements are 1
A random element of matrix is selected and changed from 1 to -1.
The process goes till all the elements are changed from 1 to -1 randomly.
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

Answer 1

James Tursa 2016-5-24

编辑：James Tursa 2016-5-24

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)
    :

Offroad Jeep 2016-5-24

Thanks..........