why validateFcns is not working in my nlmpc Code?

For your convinence i have attached the requird files that will save the copy paste time

% Parameters of SIRC model

n1=nlmpc(4,4,1);

Zero weights are applied to one or more OVs because there are fewer MVs than OVs.

n1.PredictionHorizon=100;
n1.ControlHorizon=10;
n1.Ts=1;
n1.Model.StateFcn="sircstatefcn";
n1.Model.OutputFcn="sircoutput";
S0      = 0.1;    % Initial susceptible population
I0      = 0.3;    % Initial infected population 
R0      = 0.5;        % Initial recovered population 
C0      = 0.1;   
x0      = [S0, I0, R0, C0]; % Initial conditions
u0=0.2;
validateFcns(n1,x0,u0)

Error using nlmpc/validateFcns
Function sircstatefcn does not exist.

function dx = sircstatefcn(x,u,p)
p.mu    = 0.015;       
p.alpha = 100;      
p.delta = 0.625;      
p.gamma	= 0.30;
p.sigma= 0.1;
p.beta0	= 0.5; 
fx=zeros(4,1);
fx(1)=p.mu*(1-x(1)) + p.gamma*x(4);
fx(2)= -(p.mu + p.alpha)*x(2);
fx(3)=p.alpha*x(2) - (p.mu + p.delta)*x(3);
fx(4)=p.delta*x(3) - (p.mu + p.gamma)*x(4);
gx=zeros(4,1);
gx(1)=-x(2)*x(1);
gx(2)=x(2)*x(1) + p.sigma*x(4)*x(2);
gx(3)=(1-p.sigma)*x(2)*x(4);
gx(4)=-x(4)*x(2);
dx=fx+gx*u;
%original state space model
% dx = [ p.mu*(1-x(1)) - u(1)*x(2)*x(1) + p.gamma*x(4);
%        u(1)*x(2)*x(1) + p.sigma*u(1)*x(4)*x(2) - (p.mu + p.alpha)*x(2);
%        (1-p.sigma)*u(1)*x(2)*x(4) + p.alpha*x(2) - (p.mu + p.delta)*x(3);
%        p.delta*x(3) - u(1)*x(4)*x(2) - (p.mu + p.gamma)*x(4)];
    
    dx=dx';
end

function y= sircoutput(x,u)
y(1)=x(1);
y(2)=x(2);
y(3)=x(3);
y(4)=x(4);
y=y';
end

Please copy both function and make seperate code files for them and then make seperate file for nlmpc evaluation and then execute the code.You will see the required error i was gettin which is ---------------------------------------------------

Error using nlmpc/validateFcns

Expecting 2 input arguments but "Model.StateFcn" appears to take 3 inputs.

Error in nmpcseir (line 15)

validateFcns(n1,x0,u0)

Answer 1

[Walter Roberson]

The problem is that when you specify a character vector for the function, then the function cannot be a local function (must have it's own .m file)

But you have another problem:

% Parameters of SIRC model

n1=nlmpc(4,4,1);

Zero weights are applied to one or more OVs because there are fewer MVs than OVs.

n1.PredictionHorizon=100;
n1.ControlHorizon=10;
n1.Ts=1;
n1.Model.StateFcn=@sircstatefcn;
n1.Model.OutputFcn=@sircoutput;
S0      = 0.1;    % Initial susceptible population
I0      = 0.3;    % Initial infected population 
R0      = 0.5;        % Initial recovered population 
C0      = 0.1;   
x0      = [S0, I0, R0, C0]; % Initial conditions
u0=0.2;
validateFcns(n1,x0,u0)

Error using nlmpc/validateFcns
Expecting 2 input arguments but "Model.StateFcn" appears to take 3 inputs.

function dx = sircstatefcn(x,u,p)
p.mu    = 0.015;       
p.alpha = 100;      
p.delta = 0.625;      
p.gamma	= 0.30;
p.sigma= 0.1;
p.beta0	= 0.5; 
fx=zeros(4,1);
fx(1)=p.mu*(1-x(1)) + p.gamma*x(4);
fx(2)= -(p.mu + p.alpha)*x(2);
fx(3)=p.alpha*x(2) - (p.mu + p.delta)*x(3);
fx(4)=p.delta*x(3) - (p.mu + p.gamma)*x(4);
gx=zeros(4,1);
gx(1)=-x(2)*x(1);
gx(2)=x(2)*x(1) + p.sigma*x(4)*x(2);
gx(3)=(1-p.sigma)*x(2)*x(4);
gx(4)=-x(4)*x(2);
dx=fx+gx*u;
%original state space model
% dx = [ p.mu*(1-x(1)) - u(1)*x(2)*x(1) + p.gamma*x(4);
%        u(1)*x(2)*x(1) + p.sigma*u(1)*x(4)*x(2) - (p.mu + p.alpha)*x(2);
%        (1-p.sigma)*u(1)*x(2)*x(4) + p.alpha*x(2) - (p.mu + p.delta)*x(3);
%        p.delta*x(3) - u(1)*x(4)*x(2) - (p.mu + p.gamma)*x(4)];
    
    dx=dx';
end

function y= sircoutput(x,u)
y(1)=x(1);
y(2)=x(2);
y(3)=x(3);
y(4)=x(4);
y=y';
end

[AMAN]

i had shared the m files of all functions i am using please take a look at those

[Walter Roberson]

When I download the files, I get the same issue

Expecting 2 input arguments but "Model.StateFcn" appears to take 3 inputs.

You declare p as being in input parameter but you never use any property of p that you do not assign to. I suggest that you remove p as being an input parameter,

function dx = sircstatefcn(x,u)

[AMAN]

yes not declaingring p in function works thank you