What is wrong with my codes?

1

I am a new CVX learner.I don’t know what is wrong with my code to solve a QP problem

H=[1,0,-1,0;0,1,0,-1;-1,0,1,0;0,-1,0,1];
A=[-1,0,0,0;0,-1,0,0;1,2,0,0;0,0,0,-1;0,0,-1,-1;0,0,1,2];
b=[0,0,2,-2,-3,6];
cvx_begin
variable x(4);
minimize(x'*H*x);
subject to
A*x <= b;
cvx_end

It reports errors:

Error using cvxprob/newcnstr (line 87)
Matrix dimensions must agree.

Error in cvx/le (line 21)
b = newcnstr( evalin( ‘caller’, ‘cvx_problem’, ‘[]’ ), x, y, ‘<=’ );

2

your code must be as follow:
H=[1,0,-1,0;0,1,0,-1;-1,0,1,0;0,-1,0,1];
A=[-1,0,0,0;0,-1,0,0;1,2,0,0;0,0,0,-1;0,0,-1,-1;0,0,1,2];
b=[0,0,2,-2,-3,6];
cvx_begin
variable x(4,1);
minimize(x.‘Hx);
subject to
A*x <= b.’;
cvx_end

3

variable x(4) is the same as variable x(4,1), so the only change really needed is the b’ . That is really just a matter of getting dimensions correct in MATLAB, and not really a CVX-specific matter.