請問下面為何無法交易？但只要把Power(2, i)改成Power(i,2)即可交易？

 var:i(0); 

 Array: up[16](0),mid[16](0),down[16](0);

//計算布林通道值

  for i = 2 to 16 

begin

up[i] = bollingerband(Close, Power(2, i), 2); //上軌

mid[i] = average(close, Power(2, i)); //均線

down[i] = bollingerband(Close, Power(2, i), -2); //下軌

end;

 SetPosition(1, MARKET);