R:按列组应用Holt Winters来预测时间序列

我有一个频率= 7的时间序列数据如下:

combo_1_daily_mini <-   read.table(header=TRUE, text="
region_1    region_2    region_3    date    incidents
USA CA  San Francisco   1/1/15  37
USA CA  San Francisco   1/2/15  30
USA CA  San Francisco   1/3/15  31
USA CA  San Francisco   1/4/15  33
USA CA  San Francisco   1/5/15  28
USA CA  San Francisco   1/6/15  33
USA CA  San Francisco   1/7/15  39
USA PA  Pittsburg   1/1/15  38
USA PA  Pittsburg   1/2/15  35
USA PA  Pittsburg   1/3/15  37
USA PA  Pittsburg   1/4/15  33
USA PA  Pittsburg   1/5/15  30
USA PA  Pittsburg   1/6/15  33
USA PA  Pittsburg   1/7/15  25
Greece  Macedonia   Skopje  1/1/15  29
Greece  Macedonia   Skopje  1/2/15  37
Greece  Macedonia   Skopje  1/3/15  28
Greece  Macedonia   Skopje  1/4/15  38
Greece  Macedonia   Skopje  1/5/15  27
Greece  Macedonia   Skopje  1/6/15  38
Greece  Macedonia   Skopje  1/7/15  39
Italy   Trentino    Trento  1/1/15  35
Italy   Trentino    Trento  1/2/15  31
Italy   Trentino    Trento  1/3/15  34
Italy   Trentino    Trento  1/4/15  34
Italy   Trentino    Trento  1/5/15  26
Italy   Trentino    Trento  1/6/15  33
Italy   Trentino    Trento  1/7/15  27
", sep = "\t")

dput(trst,  control = "all")
structure(list(region_1 = structure(c(3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L), .Label = c("Greece", "Italy", "USA"), class = "factor"), 
region_2 = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 4L, 4L, 4L, 
4L, 4L, 4L, 4L), .Label = c("CA", "Macedonia", "PA", "Trentino"
), class = "factor"), region_3 = structure(c(2L, 2L, 2L, 
2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 4L), .Label = c("Pittsburg", 
"San Francisco", "Skopje", "Trento"), class = "factor"), 
date = structure(c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 1L, 2L, 3L, 
4L, 5L, 6L, 7L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 1L, 2L, 3L, 4L, 
5L, 6L, 7L), .Label = c("1/1/15", "1/2/15", "1/3/15", "1/4/15", 
"1/5/15", "1/6/15", "1/7/15"), class = "factor"), incidents = c(37L, 
30L, 31L, 33L, 28L, 33L, 39L, 38L, 35L, 37L, 33L, 30L, 33L, 
25L, 29L, 37L, 28L, 38L, 27L, 38L, 39L, 35L, 31L, 34L, 34L, 
26L, 33L, 27L)), .Names = c("region_1", "region_2", "region_3", 
"date", "incidents"), class = "data.frame", row.names = c(NA, 
-28L))

region_1,region_2,region_3的每一组都有自己的季节性和趋势.

我试图根据历史数据预测下一周的事故数量.我有2015年1月1日至2015年6月30日为32个不同国家的6个月历史数据.每个国家/地区都有很多region_2和region_3.我总共有32,356个独特的region_1,region_2,region_3时间序列.

我有2个问题/问题:

问题 - 我面临的问题是当我在by()函数中应用Holt Winters时,我收到警告并且我无法理解它们.任何帮助理解它们都非常有帮助

以下是我的代码:

ts_fun <- function(x){
  ts_y <- ts(x, frequency = 7)
}

hw_fun <- function(x){
    ts_y <- ts_fun(x)
    ts_h <- HoltWinters(ts_y) 
} 

combo_1_daily_mini$region_1 <- as.factor(combo_1_daily_mini$region_1)
combo_1_daily_mini$region_2 <- as.factor(combo_1_daily_mini$region_2)
combo_1_daily_mini$region_3 <- as.factor(combo_1_daily_mini$region_3)

combo_1_ts <- by(combo_1_daily_mini,list(combo_1_daily_mini$region_1,
                                     combo_1_daily_mini$region_2, 
                                     combo_1_daily_mini$region_3
                                     ),ts_fun)

combo_1_hw <- by(combo_1_daily_mini,list(combo_1_daily_mini$region_1,
                                     combo_1_daily_mini$region_2, 
                                     combo_1_daily_mini$region_3
                                     ),hw_fun)

警告信息:

1: In HoltWinters(ts_y) :
 optimization difficulties: ERROR: ABNORMAL_TERMINATION_IN_LNSRCH
2: In HoltWinters(ts_y) :
 optimization difficulties: ERROR: ABNORMAL_TERMINATION_IN_LNSRCH
3: In HoltWinters(ts_y) :
 optimization difficulties: ERROR: ABNORMAL_TERMINATION_IN_LNSRCH
4: In HoltWinters(ts_y) :
 optimization difficulties: ERROR: ABNORMAL_TERMINATION_IN_LNSRCH

问题 - 我通过多列正确应用函数的方式是什么？有没有更好的办法？我基本上希望通过region_1,region_2,region_3获得下周的预测数字.我计划使用以下代码:

nw_forecast < - forecast(combo_1_hw,7)

我可以应用Holt Winters功能,还可以预测每个region_1,region_2,region_3组合创建时间序列数据的时间.此方法不可行,因为我的数据集中有32,356个唯一组合.

任何帮助表示赞赏谢谢