R包预测中auto.arima的奇异行为
我试图使用R-package forecast来拟合arima模型(使用函数arima)并自动选择合适的模型(使用函数auto.arima)。我首先用Arima函数估计了两种可能的模型:R包预测中auto.arima的奇异行为,r,time-series,forecasting,R,Time Series,Forecasting,我试图使用R-package forecast来拟合arima模型(使用函数arima)并自动选择合适的模型(使用函数auto.arima)。我首先用Arima函数估计了两种可能的模型: tt.1 <- Arima(x, order=c(1,0,1), seasonal=list(order=c(0,1,1)), include.drift=F) tt.2 <- Arima(x, order=c(1,0,1), seasonal=list(order=c
tt.1 <- Arima(x, order=c(1,0,1), seasonal=list(order=c(0,1,1)),
include.drift=F)
tt.2 <- Arima(x, order=c(1,0,1), seasonal=list(order=c(0,1,0)),
include.drift=F)
以下是Arima计算的模型摘要:
> summary(tt.1)
Series: x
ARIMA(1,0,1)(0,1,1)[96]
Coefficients:
ar1 ma1 sma1
0.9273 -0.5620 -1.0000
s.e. 0.0146 0.0309 0.0349
sigma^2 estimated as 867.7: log likelihood=-5188.98
AIC=10385.96 AICc=10386 BIC=10405.81
Training set error measures:
ME RMSE MAE MPE MAPE MASE ACF1
Training set 0.205128 28.16286 11.14871 -7.171098 18.42883 0.3612059 -0.03466711
> summary(tt.2)
Series: x
ARIMA(1,0,1)(0,1,0)[96]
Coefficients:
ar1 ma1
0.9148 -0.4967
s.e. 0.0155 0.0320
sigma^2 estimated as 1892: log likelihood=-5481.93
AIC=10969.86 AICc=10969.89 BIC=10984.75
Training set error measures:
ME RMSE MAE MPE MAPE MASE ACF1
Training set 0.1942746 41.61086 15.38138 -8.836059 24.55919 0.49834 -0.02253845
注:我不允许提供数据。但如果有必要,我很乐意提供更多的输出或运行修改过的函数调用
编辑:我现在查看了auto.arima的源代码,发现该行为是由根上的检查引起的,该检查设置了用于在模型未通过检查时选择模型的信息标准。《auto.arima帮助》中引用的论文证实(Hyndman,R.J.和Khandakar,Y.(2008)“自动时间序列预测:R的预测包”,《统计软件杂志》,26(3),第11页)。对不起,我应该在这里提问之前先看一下报纸
auto.arima
试图找到受某些约束的最佳模型,避免使用参数接近非平稳性和非可逆性边界的模型
您的tt.1
模型的季节性MA(1)参数为-1,位于不可逆边界上。所以你不想使用这个模型,因为它会导致数值不稳定。季节性差分算子与季节性MA算子混淆
在内部,
auto.arima
为任何不满足约束条件的模型提供Inf
的AIC/AICc/BIC值,以避免其被选中。感谢您的回答!正如我在底部的问题(编辑部分)中所写的那样,我已经通过查看源代码和auto.arima帮助中提到的论文了解到了这一点。再次抱歉,在阅读“帮助”中提到的论文之前提出了一个问题!我接受了你的回答。
ARIMA(0,0,0)(0,1,0)[96] : 11744.63
ARIMA(0,0,0)(0,1,1)[96] : Inf
ARIMA(0,0,0)(1,1,0)[96] : Inf
ARIMA(0,0,0)(1,1,1)[96] : Inf
ARIMA(0,0,1)(0,1,0)[96] : 11404.67
ARIMA(0,0,1)(0,1,1)[96] : Inf
ARIMA(0,0,1)(1,1,0)[96] : Inf
ARIMA(0,0,1)(1,1,1)[96] : Inf
ARIMA(1,0,0)(0,1,0)[96] : 11120.72
ARIMA(1,0,0)(0,1,1)[96] : Inf
ARIMA(1,0,0)(1,1,0)[96] : Inf
ARIMA(1,0,0)(1,1,1)[96] : Inf
ARIMA(1,0,1)(0,1,0)[96] : 10984.75
ARIMA(1,0,1)(0,1,1)[96] : Inf
ARIMA(1,0,1)(1,1,0)[96] : Inf
ARIMA(1,0,1)(1,1,1)[96] : Inf
> summary(tt.1)
Series: x
ARIMA(1,0,1)(0,1,1)[96]
Coefficients:
ar1 ma1 sma1
0.9273 -0.5620 -1.0000
s.e. 0.0146 0.0309 0.0349
sigma^2 estimated as 867.7: log likelihood=-5188.98
AIC=10385.96 AICc=10386 BIC=10405.81
Training set error measures:
ME RMSE MAE MPE MAPE MASE ACF1
Training set 0.205128 28.16286 11.14871 -7.171098 18.42883 0.3612059 -0.03466711
> summary(tt.2)
Series: x
ARIMA(1,0,1)(0,1,0)[96]
Coefficients:
ar1 ma1
0.9148 -0.4967
s.e. 0.0155 0.0320
sigma^2 estimated as 1892: log likelihood=-5481.93
AIC=10969.86 AICc=10969.89 BIC=10984.75
Training set error measures:
ME RMSE MAE MPE MAPE MASE ACF1
Training set 0.1942746 41.61086 15.38138 -8.836059 24.55919 0.49834 -0.02253845