I am encountering this error in my simulation, I wrote the left part of the fourth constraint as BELTA,my objective function is set to maximize belta. please tell me where my error occurs.

Here is my equation and simulation code

clc;

clear;

load citys

load M_star

xb = 0;xe = 1000;%起始点和终点

vmax = 30; %m/s

T = 40;

N = 100;

num_SNs = 10;

Smax = 2;

H = 30;

delta_t = T/N;

V = vmax*delta_t;
RL = zeros(Smax,N);
iter_num = 10;
Yu0 = zeros(1,N);
citys_co = zeros(Smax,N,2);
for n = 1:1:N
Xu0(n) = xb + (n - 1)*(xe - xb)/(N - 1);

end

for ii = 1:Smax

for kk = 1:N

city_indices = M_star(ii, kk); % 获取第i个城市的序号

citys_co(ii,kk,1) = citys(city_indices, 1); % 获取城市的坐标

citys_co(ii,kk,2) = citys(city_indices, 2); %Y坐标

end

end

for iter=1:iter_num

cvx_begin

variable belta

variable x(1,N)

variable BELTA_1(1,N)

variable BELTA

variable qq(Smax,N)

```
maximize(belta)
subject to
% trajectory
x(1) = xb;
x(N) = xe;
for kk=1:N-1
square_pos(x(kk+1)-x(kk))<=(V)^2;
end
for ii = 1:Smax
for jj = 1:N
sum_inner = 0;
for jjj = ii+1:Smax
sum_inner = sum_inner + inv_pos(qq(ii,jj));
end
BELTA_1(jj,ii) = BELTA_1(ii,jj) + (pow_abs((x(jj) - citys_co(ii,jj,1)),2) - (pow_abs((Xu0(jj)-citys_co(ii,jj,1)),2)));
end
end
BELTA = sum(BELTA_1);
for ii = 1:Smax
for jj = 1:N
qq(ii,jj) <= pow_abs(Xu0(jj)-citys_co(ii,jj,1),2) + 2*(Xu0(jj)-citys_co(ii,jj,1))*(x(jj)-Xu0(jj));
end
end
BELTA >= belta;
```

cvx_end

end