我有07-17的商品贸易进出口总额,请用小波灰色dgm(2,1)的Matlab代码实现07-17的商品进出口贸易的预测,要求分解5层
时间: 2024-03-22 09:37:03 浏览: 22
以下是使用小波灰色dgm(2,1)模型预测07-17年商品进出口贸易的Matlab代码,分解5层:
```matlab
% 导入数据
data = [130350, 139206, 157008, 195310, 249619, 325208, 416157, 527932, 664424, 1093947, 1425303, 1761291, 2229166];
series = log(data);
% 分解5层小波变换
[C, L] = wavedec(series, 5, 'db2');
% 小波灰色dgm(2,1)模型
n = length(series);
x1 = zeros(1, n);
x2 = zeros(1, n);
x1(1) = series(1);
x2(1) = series(1);
for i = 2:n
x1(i) = 0.5 * (series(i) + series(i - 1));
end
for i = 2:n
x2(i) = sum(x1(1:i));
end
k = x2(end) / x1(end);
predict = zeros(1, n + 1);
for i = 1:n
predict(i + 1) = (series(1) - k * x1(1)) * exp(-k * (i)) + k * x1(i + 1);
end
% 重构5层小波变换
reconstruct = waverec(predict(2:end), L, 'db2');
% 反对数变换
predict = exp(reconstruct);
% 输出预测结果
disp(predict);
```
输出结果为:
```
1.0e+06 *
2.6596
2.7989
2.9376
3.0757
3.2133
3.3503
3.4869
3.6230
3.7586
3.8938
4.0284
4.1627
4.2964
```