Generate values with constrains

Hello,

I am new to matlab and I would like to generate several temperatures (V)s to cover a time duration (Tmax). Vmin <= V <= Vmax. The initial temperature in the room V(t=0)=V0=0; The temperature (V) can be found using thde function:

V(i)=V(i-1)+A*(t(i)-t(i-1));

"A " is picked randomly from A, but with no direct repetition. For example:

A1, A1, A0 , A2 not acceptable since A1 is followed by A1

A1,A2,A0,A1,A2,A2 not accepted since A2 is followed by A2

A1,A2,A0,A1.A0 accpeted

A1,A0,A1,A0,A1 accepted

The number of schedules =10;

Can someone help me please with writting the code. Here is my model.

%% This code is to generate set of temperatures between vmin and Vmax to cover a given time
%
%-------------------------------------------------------------------------%
clear variables; 
close all;ddd
clc;
%------------------------------------------------------------------------%

%% Defining Units
%------------------------------------------------------------------------%
A=[-4 4/3 2];  
v0=0;          % Initial temperature
t0=0;          % Initial time
Tmax=7;        % Total time   
Vmax=5;        % Maximum temperature
Vmin=-1;       % Minimum temperature
n=10;          % Number of itterations (schedules)
n1=nan;

%-------------------------------------------------------------------------%
for i = 1:n 
    while t<=Tmax
    V(i)=V(i-1)+(randi(A)*(rand-t(i-1)));
    if V(i)>Vmax || V<Vmin
            V(i)=A*(rand-t);
    else 
    % Do Nothing
    end
    % To avoid selecting the same A
    n2 = ind(A);
    while n1 == n2
        n2 = randi(A);
    end
    V(i)= [V, n2];
    n1 = n2;
    end
end

[Walter Roberson]

Your random selection can be improved. Generate a random index with

NA - length(A);

i1 = randi(NA);
n1 = A(i1);

After that, you can get a different random entry without direct repetitions by using

i2 = randi(NA-1);
i2 = i2 + (i2 >= i1);
n2 = A(i2);

[Hamzah Faraj]

Hello Walter, Thanks for your tips. Can I ask you to add this to the code. As I said earlier I’m new to coding area and can’t get it immediately. Thanks again

Answer 1

[Hamzah Faraj]

idxr = randi(length(a),1,10); %// create the first batch of numbers
idx = diff(idxr)==0; %// logical array, where 1s denote repetitions for first batch
while nnz(idx)~=0
    idx = diff(idxr)==0; %// logical array, where 1s denote repetitions for
                      %// subsequent batches
    rN = randi(length(a),1,nnz(idx)); %// new set of random integers to be placed
                             %// at the positions where repetitions have occured
    idxr(find(idx)+1) = rN; %// place ramdom integers at their respective positions
end
modes=a(idxr);

Answer 2

[Walter Roberson]

A=[-4 4/3 2];
n = 10;

NA = length(A);

randA = zeros(1,n);

i1 = randi(NA);
randA(1) = A(i1);

for K = 2 : n
    i2 = randi(NA-1);
    i2 = i2 + (i2 >= i1);
    randA(K) = A(i2);
    i1 = i2;
end

Answer 3

[Devineni Aslesha]

To select a random value from A and to obtain different consecutive A's for every schedule can be done using randperm as well.

for i = 1:2:10
n1 = randperm(length(A));
flag = 0;
if i>1
    if n1(1) == n2
        n1(1) = n1(2);
        flag = 1;
    end
end
A1(i) = n1(1);
if flag == 1
    n2 = n1(3);
else
    n2 = n1(2);
end
A1(i+1) = n2;
end

Here, A1 is the desired output.

[Walter Roberson]

You never use n1(4) or later so there is no point in using randperm(length(A)): you might as well use randperm(length(A),3)