Function that produce an uniform random numbers for loop error

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Hi i'm having an issue in my for loop
i',m trying to make a function that produce an uniform random numbers but no matter what i adjust i keep getting the same error
clear
clc
%N=input('sequence_length')
N=5000
N = 5000
MinSec = fix(clock);
seed = 100*MinSec(5) + MinSec(6);
Urand = myrandi(seed,N);
la = 65539
P = 2.1475e+09
Index exceeds the number of array elements. Index must not exceed 1.

Error in solution>myrandi (line 33)
Urand(i)= mod(la*seed(i-1),P);
%b
%Y=ones(size(Urand));
subplot(2,1,1)
hist(Urand)
%% Task 1: : the Linear Congruential Generator (LCG)
v = rand(1,N);
%u=u./max(u);
subplot(3,2,2);
hist(v,100);
title(subplot(2,1,2),'Uniform random: rand()');
%Function that produce an uniform random numbers
%Using the technic of LCG r(k) = [lambda*r(k-1)]modulo(P)
function Urand = myrandi(seed,sequence_length)
la=65539
N=sequence_length;
P=2^31
%change N accordingly
%part a
Urand=zeros(1,N);
Urand(1)=seed;
for i=2:N
Urand(i)= mod(la*seed(i-1),P);
end
Urand=Urand/65539;
%printing genetrated vector, after dividing by 6655
if N<=50 %will print numbers only
if N<=50
disp(['for N = ',num2str(N)])
disp(Urand)
end
end
end%function myrand

Accepted Answer

KSSV
KSSV on 14 Oct 2022
This line:
Urand(i)= mod(la*seed(i-1),P);
Your seed is a scalar, it has sinlge value. You are trying to extract more number by indexing it and treating it as a vector. This is the error.
Do you mean to use:
Urand(i)= mod(la*seed*(i-1),P);
  3 Comments
Faisal Al-Wazir
Faisal Al-Wazir on 14 Oct 2022
yes now it works
clear
clc
%N=input('sequence_length')
N=5000
N = 5000
MinSec = fix(clock);
seed = 100*MinSec(5) + MinSec(6);
Urand = myrandi(seed,N);
la = 65539
P = 2.1475e+09
Urand = 1×5000
0 0.0929 0.1859 0.2788 0.3717 0.4647 0.5576 0.6505 0.7434 0.8364 0.9293 0.0222 0.1152 0.2081 0.3010 0.3940 0.4869 0.5798 0.6727 0.7657 0.8586 0.9515 0.0445 0.1374 0.2303 0.3233 0.4162 0.5091 0.6020 0.6950
%b
%Y=ones(size(Urand));
subplot(3,2,1)
hist(Urand)
%% Task 1: : the Linear Congruential Generator (LCG)
v = rand(1,N);
%u=u./max(u);
subplot(3,2,2);
hist(v,100);
title(subplot(3,2,2),'Uniform random: rand()');
%Function that produce an uniform random numbers
%Using the technic of LCG r(k) = [lambda*r(k-1)]modulo(P)
function Urand = myrandi(seed,sequence_length)
la=65539
N=sequence_length;
P=2^31
%change N accordingly
%part a
Urand=zeros(1,N);
seed(1)=seed;
for i=2:N
Urand(i)= mod((la*seed*(i-1)),P);
end
Urand = Urand./(P-1)
end%function myrand

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