I get an error for this code

and I use slack variable

please help me

```
cvx_begin
variable Q_new(N,2)
gama0 = P * db2pow(row0) / sigma2;
expression R(K,1);
for i = 1 :1: K
for n = 1:1: N
r = r + a(n,i) * ( (-gama0 * log2(exp(1)))/(H^2 + sum_square_abs(Q(n)-X(i,:)))/...
(H^2 + sum_square_abs(Q(n)-X(i,:)) + gama0) *...
( sum_square_abs(Q_new(n)-X(i,:))- sum_square_abs(Q(n)-X(i,:)) )...
+ log2(1 + gama0/(H^2+ sum_square_abs(Q(n)-X(i,:)))) );
end
R(i) = r;
end
expression eta_lb
maximize eta_lb
subject to
for i = 1:K
eta <= R (i);
R (i) >= eta
end
norms(Q_new(2:N)-Q(1:N-1),2,2) <= Smax^2 ;
Q_new(1) == Q_new(N);
cvx_end
```

error is

```
Error using cvxprob/newcnstr (line 192)
Disciplined convex programming error:
Invalid constraint: {constant} <= {convex}
Error in <= (line 21)
b = newcnstr( evalin( 'caller', 'cvx_problem', '[]' ), x, y, '<=' );
Error in main (line 133)
eta <= R (i);
```