Problems with Constraints

[Kaho Suzuki]

Hello,I have encountered very simple problem but I am not sure what's wrong.

The constraints of my model as follows:

C = [0.4<=soc(25)<=1.0,-0.02<=soc(1)-soc(25)<=0.02,];

for i=1:24

    C = [C,0.4<=soc(i)<=1.0,];

    C = [C,300.0<=Pc(i)<=1000.0,300.0<=Pt(i)<=1000.0,];

    C = [C,Uc(i)+Ut(i)<=1,];

end

I don't think there is anything wrong. But error occurred:

Error using constraint/horzcat (line 11)

One of the constraints evaluates to a FALSE LOGICAL variable. Your model is infeasible

Error in main1 (line 78)

C = [0.4<=soc(25)<=1.0,-0.02<=soc(1)-soc(25)<=0.02,];

Where soc is a 1*24 sdpvar and soc(1)&&soc(25) were initialized to 0.4. 

Then I changed it to the following shape:

C = [0.4<=soc(25)<=1.0,-0.02<=soc(1)-soc(25),soc(1)-soc(25)<=0.02,];

The program could be run. However, the number of constraints is 97, which should be 99 if current. 

Obviously the constraints -0.02<=soc(1)-soc(25),soc(1)-soc(25)<=0.02 was ignored.

I had thought about everything I could but didn't work. I really need your help. 

[Johan Löfberg]

You are working with constant data, not sdpvars, so according to matlab -0.02<=soc(1)-soc(25)<=0.02 evaluates to (-0.02<=soc(1)-soc(25)) <=0.02 which evaluates to (1) <= 0.02, which is trivially a false statement

You either skip adding constraints on constant data, or you fix variables by equality instead of assignment

[Johan Löfberg]

and yes, the trivial statements  [-0.02<=soc(1)-soc(25),soc(1)-soc(25)<=0.02] which evaluate to [-0.02 <= 0, 0 <= 0.02] which evaluates to [true, true] are simply removed from the model.

[Kaho Suzuki]

I know, thanks a lot !