Why does entity generation stay at 0 after using randn function?

I am using this code to try to generate random entities with the a mean of 100 and a std dev. of 10. Each time I try to run the simulation I get 0 entities generated and m=100 in the system dialog. How do I change the code to generate random entities?

persistent rngInit;
if isempty(rngInit)
    seed = 12345;
    rng(seed);
    rngInit = true;
end

% Pattern: Gaussian (normal) distribution
% m: Mean, d: Standard deviation
m = 100, d = 10;
dt = m + d * randn;

[David Goodmanson]

HI Sebastian, It might be worth looking at trying 'exist randn' (see 'help exist' at some opportune places in the code. If the answer is 5, it's hard to see how what you got could not work, but if it's ~=5 then something is not right.

Answer 1

[Walter Roberson]

If your dt is coming out empty, then at some point you assigned [] to randn

[Sebastian Stankiewicz]

Can this happen at any point? For right now this is the only code that I have in the script. If I had previously assigned [] to randn, would it have it saved?

[Jan]

You can check the value of randn:

which randn -all

If you have defined

randn = []

anywhere and use scripts, the original function is "shadowed". Either remove the definition as a variable:

clear randn

or use functions, which have the great benefit compared to scripts, that they do niot import any typo from the command window and all other scripts.

Answer 2

[John BG]

Chema Sebastian

this is John BG <mailto:[e-mail] [e-mail]>

1. tried randn in MATLAB online

    N=12;
    mu = 100*ones(N,1);
    sigma = 10*ones(N,1);
    z = mu+ randn(N,1).*sigma

    z =
      121.1303
       96.8988
       96.5285
       86.7920
      102.1630
      105.4597
      113.7002
      108.0667
      106.5743
      102.7673
      112.2676
      104.2776

2.

checked rng status

scurr=rng
scurr = 

    struct with fields:

       Type: 'twister'
       Seed: 12345
      State: [625×1 uint32]

3.

provided randn is told to generate N different random values.

Otherwise, when not passing arguments to randn

N=12;
mu = 100*ones(N,1);
sigma = 10*ones(N,1);
z = mu+ randn*sigma
z =

     88.4374
     88.4374
     88.4374
     88.4374
     88.4374
     88.4374
     88.4374
     88.4374
     88.4374
     88.4374
     88.4374
     88.4374

randn only spins the roulette once.

4.

In any case the result is not empty.

When you say 'empty' do you really mean 'not random'?

if you find this answer useful would you please be so kind to consider marking my answer as Accepted Answer?

To any other reader, if you find this answer useful please consider clicking on the thumbs-up vote link

thanks in advance

John BG

<mailto:[e-mail] [e-mail]>