给我写一个计算封闭多边形knot energy的matlab程序

以下是一个简单的计算封闭多边形knot energy的matlab程序：

% 首先输入多边形的顶点坐标
x = [1,2,4,5,4,2];
y = [1,3,3,1,-1,-3];

% 计算多边形的长度
L = 0;
for i = 1:length(x)-1
    L = L + norm([x(i+1)-x(i), y(i+1)-y(i)]);
end
L = L + norm([x(1)-x(end), y(1)-y(end)]);

% 计算每个顶点角度
theta = zeros(1,length(x));
for i = 1:length(x)
    if i == 1
        theta(i) = atan2(y(i+1)-y(i), x(i+1)-x(i)) - atan2(y(end)-y(i), x(end)-x(i));
    elseif i == length(x)
        theta(i) = atan2(y(1)-y(i), x(1)-x(i)) - atan2(y(i-1)-y(i), x(i-1)-x(i));
    else
        theta(i) = atan2(y(i+1)-y(i), x(i+1)-x(i)) - atan2(y(i-1)-y(i), x(i-1)-x(i));
    end
end

% 计算knot energy
E = 0;
for i = 1:length(x)
    E = E + (theta(i)^2);
end
E = E/L;

disp(['The knot energy of the polygon is ', num2str(E)]);

这个程序将计算输入多边形的knot energy，并输出结果。