a = 34441;
t = 11254417; % mod value
b = 4752782;  %increment
n = 3703 %no of samples
r = zeros(1, n);
x = zeros(1, n)
x(1) = 13

for i = 2:n
    x(i + 1) = mod((x(i) * a + b), t);
   r(i) = x(i + 1) / t; %normalize to 0 to 1
end

figure;
histogram(r, 50);

% Chi square
------------------------------------------------------
a = 34441;
t = 11254417; % mod value
b = 4752782;  %increment
n = 37000 %no of samples
r = zeros(1, n);
x = zeros(1, n)
x(1) = 13

for i = 2:n
    x(i + 1) = mod((x(i) * a + b), t);
   r(i) = x(i + 1) / t; %normalize to 0 to 1
end

%figure;
%histogram(r, 50);

bins = 10;
edges = linspace(0, 1, bins + 1);
obs = histcounts(r, edges);
exp = n / bins;

sum = 0;
for i = 1:bins
    sum = sum + (obs(i) - exp)^2 / exp;
end;

alpha = 0.05;
df = bins - 1;

chicritical = chi2inv(1 - alpha, df);

if sum < chicritical
    fprintf("ACCEPTED, UNIFORM");
else
    fprintf("REJECTED, NOT UNIFORM");
end


nor = zeros(1, n);
me = mean(r);
sd = std(r);
for i = 1:n
    nor(i) = (r(i) - me) / sd;
end
autocorr(nor);