how create matrix 8*8

Hi, can someone help me with this code

I want to create a 8*8 matrix using equation

No value should be repeated within the array

That is, each value in the array appears one time only.

clear all;clc;
r=0.2;x(1,1)=0.8;
for i=2:64
x(i)=r+(1-x(i-1))^2;
end
A=reshape(x,8,[]);
for i=1:8
    for j=1:8
      allma(i,j)=A(i,j);
  end
end
ssA= [];b=[]
   for i=1: 8
       for j=1:8
           ZZZZ=A(i,j);
       ssA(i,j)=round(mod(ZZZZ*10^5,256));
            end
   end
   
ssA =
   128   151   252   249    49   224   191   178
   192    60    40    63   172   217   235   242
   192   145    73   180    21   213   187   176
   114    69   136   100   187   223   237   243
    43    11   190   126   255   204   183   175
     2    16   212   130   200   228   239   244
    86   225    80    83   238   197   180   173
   220   174    15   154   209   232   241   245

[Jan]

allma is not used anywhere, so you can omit the corresponding two loops.

A faster version for the final loops:

ssA = round(mod(A*1e5, 256));

So you do not need loops for this.

[Jan]

@sarah: Please do not remove important parts of the question, because this let the answers become useless for other readers. The nature of this forum is that voluntary other users helps you to solve your problem, but this is not a cheap debugging service, but thought for sharing solutions ith the community. Then deleteing parts of the question is a missusage of the work of the persons, who help you.

[Jan]

@sarah: You have removed the code again in this and several other of your questions. If you have a good reasons to delete it, contact one of the editors or the admins of the forum and explain the problem.

With participating in this forum, you agree with the Guidelines .

For the readers: Here is the code which was part of the question initially:

clear all;clc;
r=0.2;x(1,1)=0.8;
for i=2:64
x(i)=r+(1-x(i-1))^2;
end
A=reshape(x,8,[]);
for i=1:8
    for j=1:8
      allma(i,j)=A(i,j);
  end
end
ssA= [];b=[]
   for i=1: 8
       for j=1:8
           ZZZZ=A(i,j);
       ssA(i,j)=round(mod(ZZZZ*10^5,256));
            end
   end
   
ssA =
   128   151   252   249    49   224   191   178
   192    60    40    63   172   217   235   242
   192   145    73   180    21   213   187   176
   114    69   136   100   187   223   237   243
    43    11   190   126   255   204   183   175
     2    16   212   130   200   228   239   244
    86   225    80    83   238   197   180   173
   220   174    15   154   209   232   241   245

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Jan]

Your code does not produce unique values. To obtain uniqueness the 8*8 elements must contain the values from 0 to 63:

v   = 0:63;
ssA = reshape(v(randperm(numel(v))), 8, 8)

Or with more possible values:

v   = 0:255;
ssA = reshape(v(randperm(numel(v), 64)), 8, 8)

This solution is working, but does not use your equation x(i)=r+(1-x(i-1))^2 . If using this is required, collect the needed 64 unique elements at first:

x     = zeros(8, 8);
r     = 0.2;
xi    = 0.8;
x(1)  = round(mod(xi*1e5, 256));
k     = 2;
limit = 1e7;                 % Avoid infinite loop
count = 0;
while k < 64 && count < limit
    xi = r + (1 - xi)^2;
    xr = round(mod(xi * 1e5, 256));
    if ~any(x(1:k-1) == xr)  % Check if value is new
        x(k) = xr;           % Store new value
        k    = k + 1;        % Proceed to next element
    end
    count = count + 1;       % Advance security counter
end

if count > limit
    error('Cannot find 64 different values in %d iterations.', limit)
end

[sarah]

thank you so much

[Image Analyst]

I've accepted Jan's answer since sarah forgot to.