Using a MATLAB function-block in Simulink to generate random numbers

Question

Niklas 2014-6-25

1
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/137534-using-a-matlab-function-block-in-simulink-to-generate-random-numbers

评论： A Jenkins 2014-6-25

Hello!

I've tried to both google this question and search among the questions and answers here, but I've found no definitve answer to my question so I'm making a new one. Hopefully it won't be too much trouble!

I'm creating a simulation in Simulink where I have a "MATLAB function"-block that is supposed to take input from another source (we can consider this source a "Constant"-block) and then apply a random number that is generated from the MATLAB function-block on the input.

My problem is that I get the exact same randomized numbers every single time I run the Simulink simulation. And I was wondering if someone could help me solve my problem?

Here is the code (not all of it, but all of it that matters):

    % function MC_output = randomizer(Stat_input)
%#codegen
    minrand = 0.1;
    maxrand = 1.9;
    points = 10;
    rand_numbers = Stat_input*minrand + rand(1, points).*(maxrand-minrand);
    MC_output = mean(rand_numbers);
end

I've read about this solution, but it doesn't work for me

    coder.extrinsic('rng');
    rng('shuffle');

In different ways but with no success. Some help would be greatly appriciated! Oh, and btw, I'm using MATLAB R2012a.

Thanks in advance, Niklas

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Answer 1

A Jenkins 2014-6-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/137534-using-a-matlab-function-block-in-simulink-to-generate-random-numbers#answer_142420

在 MATLAB Online 中打开

Add also:

coder.extrinsic('rand')

to the beginning of your code.

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Niklas 2014-6-25

在 MATLAB Online 中打开

After adding that MATLAB tells me that the line:

rand_numbers = Stat_input*minrand + rand(1).*(maxrand-minrand);

Gets the following error:

Expected either a logical, char, int, fi, single, or double. Found an mxArray. MxArrays are returned from calls to the MATLAB interpreter and are not supported inside expressions. They may only be used on the right-hand side of assignments and as arguments to extrinsic functions.

Any idea why?

A Jenkins 2014-6-25

在 MATLAB Online 中打开

function MC_output = fcn(Stat_input)
coder.extrinsic('rng');
coder.extrinsic('rand')
rng('shuffle');
minrand = 0.1;
maxrand = 1.9;
points = 10;
z=zeros(1, points);
z=rand(1, points);
rand_numbers = Stat_input*minrand + z.*(maxrand-minrand);
MC_output = mean(rand_numbers);
end