model is infeasible and unbounded in Matlab

Good afternoon,

Currently I wanna run the programming like:
min{ x*Mx+mx}
s.t. A0*x=b0;
A1*x<b1.
and my code about Gurobi parts as follows:

%Gurobi Define
for i=1:8*N
model.varnames{i} = sprintf('x[%d]',i);
end
model.Q = sparse(M);
model.A = sparse([A0;A1]);
model.obj = m;
model.sense = [repmat('=',6*N,1);repmat('<',12*N,1)];

mmmm=[mbat,msc];
for i=1:10
b0(1:6)=-Adc*[(X(:,i)-[0;0;PP1]);Xf(:,i)];
model.rhs = [b0;b1];
results = gurobi(model);
%I=quadprog(MM,m,A1,b1,A0,b0);
u(:,i)=results.x(1:2);
uu(:,i)=I(1:2);
X(:,i+1)=Ad*X(:,i)+Bd*u(:,i)-Gd*(Cf*Xf(:,i)-PP1);
[ttttt,xxxxx]=ode45(@(ttttt,xxxxx) odefunction(ttttt,xxxxx,u(:,i),P1(i),mmmm),[0 1],X(:,i));
X(:,i+1)=xxxxx(end,:);
Xf(:,i+1)=Adf*Xf(:,i)+K*(-P1(i)+PP1-Cf*Xf(:,i));

end

then it will give me like: Model is infeasible or unbounded
Reference to non-existent field 'x'.

Error in QP (line 155)
u(:,i)=results.x(1:2);

But when I run the same code with 'quadprog', it will feasible to solve. Is that possible I cannot make A0 and A1 together to get a combined matrix? I can't figure out which part I might be wrong, Appreciate!!

Official comment

Simranjit Kaur

Gurobi Staff

June 23, 2025 02:59 Edited

This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum. Or why not try our AI Gurobot?.

Jaromił Najman

February 25, 2021 08:24

Hi,

There are a few ways to find out what is going on here. First, you could use the gurobi_write to write an LP file and analyze whether your problem looks as you expect it to be. This could help you detecting missing constraints in the case that your problem is unbounded. If your problem is infeasible, please have a look at the Knowledge Base article How do I determine why my model is infeasible?

Best regards,
Jaromił

model is infeasible and unbounded in Matlab

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