%三次指数平滑法 clear clc S=[4265.1,4316.1,4638.4,5301.7,6339.1,7582.7,7668.4,8263.5,8140.5,8174.8,8056.2,8121.5,9498.5,10491.2,10606.7,11969.1,13658.3,14258.1,15764.2,17757.9,18633.7,19445.5,18784.8,17457,18855.2,20106.3,17814.9,18912.7,19258,19433,19809.2,20213.2]; figure hold on plot(S,'b-*','linewidth',1); alpha=0.5; beta=0.5; gamma=0.3; fc=3;%预测个数 k=14;%初始取均值数据个数 n=length(S); a(1)=sum(S(1:k))/k; b(1)=(sum(S(k+1:2*k))-sum(S(1:k)))/k; s=S(1)-a(1); y=a(1)+b(1)+s(1); for i=1:n+fc-1 if i==length(S) S(i+1)=a(end)+b(end)+s(end-k+1); end a(i+1)=alpha*(S(i)-s(i))+(1-alpha)*(a(i)+b(i)); b(i+1)=beta*(a(i+1)-a(i))+(1-beta)*b(i);%趋势 s(i+1)=gamma*(S(i)-a(i)-b(i))+(1-gamma)*s(i);%周期 y(i+1)=a(i+1)+b(i+1)+s(i+1); end plot(n:n+fc,S(end-fc:end),'r-o','linewidth',1); legend('历史走势','未来走势') xlim([0,37])优化该代码

以下是优化过的代码：

clear;
clc;
S = [4265.1,4316.1,4638.4,5301.7,6339.1,7582.7,7668.4,8263.5,8140.5,8174.8,8056.2,8121.5,9498.5,10491.2,10606.7,11969.1,13658.3,14258.1,15764.2,17757.9,18633.7,19445.5,18784.8,17457,18855.2,20106.3,17814.9,18912.7,19258,19433,19809.2,20213.2];

figure;
hold on;
plot(S, 'b-*', 'linewidth', 1);

alpha = 0.5;
beta = 0.5;
gamma = 0.3;
fc = 3; % 预测个数
k = 14; % 初始取均值数据个数
n = length(S);

a = zeros(1, n + fc);
b = zeros(1, n + fc);
s = zeros(1, n + fc);
y = zeros(1, n + fc);

a(1) = sum(S(1:k)) / k;
b(1) = (sum(S(k+1:2*k)) - sum(S(1:k))) / k;
s(1) = S(1) - a(1);
y(1) = a(1) + b(1) + s(1);

for i = 1:n+fc-1
    % 计算a、b、s、y
    a(i+1) = alpha * (S(i) - s(i)) + (1 - alpha) * (a(i) + b(i));
    b(i+1) = beta * (a(i+1) - a(i)) + (1 - beta) * b(i);
    s(i+1) = gamma * (S(i) - a(i) - b(i)) + (1 - gamma) * s(i);
    y(i+1) = a(i+1) + b(i+1) + s(i+1);

    % 计算预测值并添加到S中
    if i == length(S)
        S(i+1) = a(end) + b(end) + s(end-k+1);
    end
end

plot(n:n+fc, S(end-fc:end), 'r-o', 'linewidth', 1);
legend('历史走势', '未来走势');
xlim([0, 37]);

主要的改进包括：

1. 对变量的初始化进行了优化，避免了多次重复计算；
2. 将四个变量的计算过程整合到了一起，使得代码更加简洁易懂；
3. 添加了注释，方便理解代码的含义；
4. 对格式和缩进进行了调整，使得代码更加整洁。