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Time Series Analysis and Nested Modeling of the Healthyverse Packages

Steven P. Sanderson II, MPH - Date: 17 June, 2025

This analysis follows a Nested Modeltime Workflow.

Get Data

glimpse(downloads_tbl)
## Rows: 142,521
## Columns: 11
## $ date      <date> 2020-11-23, 2020-11-23, 2020-11-23, 2020-11-23, 2020-11-23,…
## $ time      <Period> 15H 36M 55S, 11H 26M 39S, 23H 34M 44S, 18H 39M 32S, 9H 0M…
## $ date_time <dttm> 2020-11-23 15:36:55, 2020-11-23 11:26:39, 2020-11-23 23:34:…
## $ size      <int> 4858294, 4858294, 4858301, 4858295, 361, 4863722, 4864794, 4…
## $ r_version <chr> NA, "4.0.3", "3.5.3", "3.5.2", NA, NA, NA, NA, NA, NA, NA, N…
## $ r_arch    <chr> NA, "x86_64", "x86_64", "x86_64", NA, NA, NA, NA, NA, NA, NA…
## $ r_os      <chr> NA, "mingw32", "mingw32", "linux-gnu", NA, NA, NA, NA, NA, N…
## $ package   <chr> "healthyR.data", "healthyR.data", "healthyR.data", "healthyR…
## $ version   <chr> "1.0.0", "1.0.0", "1.0.0", "1.0.0", "1.0.0", "1.0.0", "1.0.0…
## $ country   <chr> "US", "US", "US", "GB", "US", "US", "DE", "HK", "JP", "US", …
## $ ip_id     <int> 2069, 2804, 78827, 27595, 90474, 90474, 42435, 74, 7655, 638…

The last day in the data set is 2025-06-15 22:20:21, the file was birthed on: 2024-08-07 07:35:44.428716, and at report knit time is -7498.74 hours old. Happy analyzing!

Now that we have our data lets take a look at it using the skimr package.

skim(downloads_tbl)
Name downloads_tbl
Number of rows 142521
Number of columns 11
_______________________
Column type frequency:
character 6
Date 1
numeric 2
POSIXct 1
Timespan 1
________________________
Group variables None

Data summary

Variable type: character

skim_variable n_missing complete_rate min max empty n_unique whitespace
r_version 102847 0.28 5 5 0 47 0
r_arch 102847 0.28 3 7 0 5 0
r_os 102847 0.28 7 15 0 22 0
package 0 1.00 7 13 0 8 0
version 0 1.00 5 17 0 60 0
country 12085 0.92 2 2 0 163 0

Variable type: Date

skim_variable n_missing complete_rate min max median n_unique
date 0 1 2020-11-23 2025-06-15 2023-07-05 1666

Variable type: numeric

skim_variable n_missing complete_rate mean sd p0 p25 p50 p75 p100 hist
size 0 1 1134346.81 1516556.82 355 14701 289918 2367728 5677952 ▇▁▂▁▁
ip_id 0 1 10431.98 18577.53 1 287 3032 11700 209747 ▇▁▁▁▁

Variable type: POSIXct

skim_variable n_missing complete_rate min max median n_unique
date_time 0 1 2020-11-23 09:00:41 2025-06-15 22:20:21 2023-07-05 07:21:17 87409

Variable type: Timespan

skim_variable n_missing complete_rate min max median n_unique
time 0 1 0 59 12H 6M 22S 60

We can see that the following columns are missing a lot of data and for us are most likely not useful anyways, so we will drop them c(r_version, r_arch, r_os)

Plots

Now lets take a look at a time-series plot of the total daily downloads by package. We will use a log scale and place a vertical line at each version release for each package.

Now lets take a look at some time series decomposition graphs.

Feature Engineering

Now that we have our basic data and a shot of what it looks like, let’s add some features to our data which can be very helpful in modeling. Lets start by making a tibble that is aggregated by the day and package, as we are going to be interested in forecasting the next 4 weeks or 28 days for each package. First lets get our base data.

## 
## Call:
## stats::lm(formula = .formula, data = df)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -146.81  -35.64  -11.12   26.91  815.18 
## 
## Coefficients:
##                                                      Estimate Std. Error
## (Intercept)                                        -1.580e+02  6.731e+01
## date                                                9.871e-03  3.565e-03
## lag(value, 1)                                       1.027e-01  2.427e-02
## lag(value, 7)                                       9.639e-02  2.516e-02
## lag(value, 14)                                      8.952e-02  2.514e-02
## lag(value, 21)                                      6.803e-02  2.522e-02
## lag(value, 28)                                      7.029e-02  2.511e-02
## lag(value, 35)                                      6.871e-02  2.516e-02
## lag(value, 42)                                      4.929e-02  2.530e-02
## lag(value, 49)                                      6.913e-02  2.518e-02
## month(date, label = TRUE).L                        -9.595e+00  5.102e+00
## month(date, label = TRUE).Q                         4.076e+00  5.093e+00
## month(date, label = TRUE).C                        -1.349e+01  5.123e+00
## month(date, label = TRUE)^4                        -7.362e+00  5.145e+00
## month(date, label = TRUE)^5                        -1.099e+01  5.107e+00
## month(date, label = TRUE)^6                        -3.303e+00  5.189e+00
## month(date, label = TRUE)^7                        -7.634e+00  5.080e+00
## month(date, label = TRUE)^8                        -3.528e+00  5.078e+00
## month(date, label = TRUE)^9                         6.018e+00  5.082e+00
## month(date, label = TRUE)^10                        3.043e+00  5.065e+00
## month(date, label = TRUE)^11                       -4.847e+00  5.139e+00
## fourier_vec(date, type = "sin", K = 1, period = 7) -1.146e+01  2.320e+00
## fourier_vec(date, type = "cos", K = 1, period = 7)  8.034e+00  2.439e+00
##                                                    t value Pr(>|t|)    
## (Intercept)                                         -2.348 0.019019 *  
## date                                                 2.769 0.005689 ** 
## lag(value, 1)                                        4.231 2.46e-05 ***
## lag(value, 7)                                        3.831 0.000133 ***
## lag(value, 14)                                       3.561 0.000381 ***
## lag(value, 21)                                       2.698 0.007058 ** 
## lag(value, 28)                                       2.800 0.005173 ** 
## lag(value, 35)                                       2.731 0.006392 ** 
## lag(value, 42)                                       1.948 0.051571 .  
## lag(value, 49)                                       2.745 0.006110 ** 
## month(date, label = TRUE).L                         -1.880 0.060223 .  
## month(date, label = TRUE).Q                          0.800 0.423666    
## month(date, label = TRUE).C                         -2.633 0.008553 ** 
## month(date, label = TRUE)^4                         -1.431 0.152674    
## month(date, label = TRUE)^5                         -2.153 0.031476 *  
## month(date, label = TRUE)^6                         -0.637 0.524505    
## month(date, label = TRUE)^7                         -1.503 0.133090    
## month(date, label = TRUE)^8                         -0.695 0.487274    
## month(date, label = TRUE)^9                          1.184 0.236560    
## month(date, label = TRUE)^10                         0.601 0.548067    
## month(date, label = TRUE)^11                        -0.943 0.345762    
## fourier_vec(date, type = "sin", K = 1, period = 7)  -4.941 8.60e-07 ***
## fourier_vec(date, type = "cos", K = 1, period = 7)   3.294 0.001008 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 58.65 on 1594 degrees of freedom
##   (49 observations deleted due to missingness)
## Multiple R-squared:  0.2383, Adjusted R-squared:  0.2278 
## F-statistic: 22.66 on 22 and 1594 DF,  p-value: < 2.2e-16

NNS Forecasting

This is something I have been wanting to try for a while. The NNS package is a great package for forecasting time series data.

NNS GitHub

library(NNS)

data_list <- base_data |>
    select(package, value) |>
    group_split(package)

data_list |>
    imap(
        \(x, idx) {
            obj <- x
            x <- obj |> pull(value) |> tail(7*52)
            train_set_size <- length(x) - 56
            pkg <- obj |> pluck(1) |> unique()
            sf <- NNS.seas(x, modulo = 7, plot = FALSE)$periods
            
            cat(paste0("Package: ", pkg, "\n"))
            NNS.ARMA.optim(
                variable = x,
                h = 28,
                training.set = train_set_size,
                #seasonal.factor = seq(12, 60, 7),
                seasonal.factor = sf,
                pred.int = 0.95,
                plot = TRUE
            )
            title(
                sub = paste0("\n",
                             "Package: ", pkg, " - NNS Optimization")
            )
        }
    )
## Package: healthyR
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 56 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.78083293164034"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 56, 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.09862816223659"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 56, 63, 21 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.02317779930191"
## [1] "BEST method = 'lin', seasonal.factor = c( 56, 63, 21 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 3.02317779930191"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 56, 63, 21 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.93875862627921"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 56, 63, 21 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.93875862627921"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 56, 63, 21 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 3.52654707244722"
## [1] "BEST method = 'both' PATH MEMBER = c( 56, 63, 21 )"
## [1] "BEST both OBJECTIVE FUNCTION = 3.52654707244722"

## Package: healthyR.ai
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 4.22663053600812"
## [1] "BEST method = 'lin', seasonal.factor = c( 63 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 4.22663053600812"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.37325863949502"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 63 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.37325863949502"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 4.11436707034228"
## [1] "BEST method = 'both' PATH MEMBER = c( 63 )"
## [1] "BEST both OBJECTIVE FUNCTION = 4.11436707034228"

## Package: healthyR.data
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 84 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.7057319939123"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 84, 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.06300423921851"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 84, 63, 56 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.87448274289272"
## [1] "BEST method = 'lin', seasonal.factor = c( 84, 63, 56 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 2.87448274289272"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 84, 63, 56 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.92408879191941"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 84, 63, 56 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.92408879191941"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 84, 63, 56 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 3.52881168692518"
## [1] "BEST method = 'both' PATH MEMBER = c( 84, 63, 56 )"
## [1] "BEST both OBJECTIVE FUNCTION = 3.52881168692518"

## Package: healthyR.ts
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.69327999126206"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63, 42 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.32182480760956"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 63, 42, 56 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 2.28243357396167"
## [1] "BEST method = 'lin', seasonal.factor = c( 63, 42, 56 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 2.28243357396167"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 63, 42, 56 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 12.3974517078415"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 63, 42, 56 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 12.3974517078415"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 63, 42, 56 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 4.48083243929011"
## [1] "BEST method = 'both' PATH MEMBER = c( 63, 42, 56 )"
## [1] "BEST both OBJECTIVE FUNCTION = 4.48083243929011"

## Package: healthyverse
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 35 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.62295455021836"
## [1] "BEST method = 'lin', seasonal.factor = c( 35 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 3.62295455021836"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 35 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.03731632785323"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 35 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.03731632785323"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 35 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 2.89982731207304"
## [1] "BEST method = 'both' PATH MEMBER = c( 35 )"
## [1] "BEST both OBJECTIVE FUNCTION = 2.89982731207304"

## Package: RandomWalker
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 70 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.84799106593199"
## [1] "BEST method = 'lin', seasonal.factor = c( 70 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 3.84799106593199"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 70 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 4.69095417721736"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 70 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 4.69095417721736"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 70 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 4.11226775030595"
## [1] "BEST method = 'both' PATH MEMBER = c( 70 )"
## [1] "BEST both OBJECTIVE FUNCTION = 4.11226775030595"

## Package: tidyAML
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 84 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 5.62576685609099"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 84, 91 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 5.4966434856712"
## [1] "BEST method = 'lin', seasonal.factor = c( 84, 91 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 5.4966434856712"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 84, 91 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 3.55568257057522"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 84, 91 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 3.55568257057522"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 84, 91 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 4.26479450273704"
## [1] "BEST method = 'both' PATH MEMBER = c( 84, 91 )"
## [1] "BEST both OBJECTIVE FUNCTION = 4.26479450273704"

## Package: TidyDensity
## [1] "CURRNET METHOD: lin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 35 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 5.14569528940359"
## [1] "NNS.ARMA(... method =  'lin' , seasonal.factor =  c( 35, 63 ) ...)"
## [1] "CURRENT lin OBJECTIVE FUNCTION = 3.84739427535103"
## [1] "BEST method = 'lin', seasonal.factor = c( 35, 63 )"
## [1] "BEST lin OBJECTIVE FUNCTION = 3.84739427535103"
## [1] "CURRNET METHOD: nonlin"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'nonlin' , seasonal.factor =  c( 35, 63 ) ...)"
## [1] "CURRENT nonlin OBJECTIVE FUNCTION = 6.71205771933361"
## [1] "BEST method = 'nonlin' PATH MEMBER = c( 35, 63 )"
## [1] "BEST nonlin OBJECTIVE FUNCTION = 6.71205771933361"
## [1] "CURRNET METHOD: both"
## [1] "COPY LATEST PARAMETERS DIRECTLY FOR NNS.ARMA() IF ERROR:"
## [1] "NNS.ARMA(... method =  'both' , seasonal.factor =  c( 35, 63 ) ...)"
## [1] "CURRENT both OBJECTIVE FUNCTION = 4.80656390322323"
## [1] "BEST method = 'both' PATH MEMBER = c( 35, 63 )"
## [1] "BEST both OBJECTIVE FUNCTION = 4.80656390322323"

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Pre-Processing

Now we are going to do some basic pre-processing.

data_padded_tbl <- base_data %>%
  pad_by_time(
    .date_var  = date,
    .pad_value = 0
  )

# Get log interval and standardization parameters
log_params  <- liv(data_padded_tbl$value, limit_lower = 0, offset = 1, silent = TRUE)
limit_lower <- log_params$limit_lower
limit_upper <- log_params$limit_upper
offset      <- log_params$offset

data_liv_tbl <- data_padded_tbl %>%
  # Get log interval transform
  mutate(value_trans = liv(value, limit_lower = 0, offset = 1, silent = TRUE)$log_scaled)

# Get Standardization Params
std_params <- standard_vec(data_liv_tbl$value_trans, silent = TRUE)
std_mean   <- std_params$mean
std_sd     <- std_params$sd

data_transformed_tbl <- data_liv_tbl %>%
  # get standardization
  mutate(value_trans = standard_vec(value_trans, silent = TRUE)$standard_scaled) %>%
  select(-value)

Since this is panel data we can follow one of two different modeling strategies. We can search for a global model in the panel data or we can use nested forecasting finding the best model for each of the time series. Since we only have 5 panels, we will use nested forecasting.

To do this we will use the nest_timeseries and split_nested_timeseries functions to create a nested tibble.

horizon <- 4*7

nested_data_tbl <- data_transformed_tbl %>%
    
    # 1. Extending: We'll predict n days into the future.
    extend_timeseries(
        .id_var        = package,
        .date_var      = date,
        .length_future = horizon
    ) %>%
    
    # 2. Nesting: We'll group by id, and create a future dataset
    #    that forecasts n days of extended data and
    #    an actual dataset that contains n*2 days
    nest_timeseries(
        .id_var        = package,
        .length_future = horizon
        #.length_actual = horizon*2
    ) %>%
    
   # 3. Splitting: We'll take the actual data and create splits
   #    for accuracy and confidence interval estimation of n das (test)
   #    and the rest is training data
    split_nested_timeseries(
        .length_test = horizon
    )

nested_data_tbl
## # A tibble: 8 × 4
##   package       .actual_data         .future_data      .splits          
##   <fct>         <list>               <list>            <list>           
## 1 healthyR.data <tibble [1,658 × 2]> <tibble [28 × 2]> <split [1630|28]>
## 2 healthyR      <tibble [1,652 × 2]> <tibble [28 × 2]> <split [1624|28]>
## 3 healthyR.ts   <tibble [1,596 × 2]> <tibble [28 × 2]> <split [1568|28]>
## 4 healthyverse  <tibble [1,566 × 2]> <tibble [28 × 2]> <split [1538|28]>
## 5 healthyR.ai   <tibble [1,391 × 2]> <tibble [28 × 2]> <split [1363|28]>
## 6 TidyDensity   <tibble [1,242 × 2]> <tibble [28 × 2]> <split [1214|28]>
## 7 tidyAML       <tibble [850 × 2]>   <tibble [28 × 2]> <split [822|28]> 
## 8 RandomWalker  <tibble [272 × 2]>   <tibble [28 × 2]> <split [244|28]>

Now it is time to make some recipes and models using the modeltime workflow.

Modeltime Workflow

Recipe Object

recipe_base <- recipe(
  value_trans ~ date
  , data = extract_nested_test_split(nested_data_tbl)
  )

recipe_base

recipe_date <- recipe_base %>%
    step_mutate(date = as.numeric(date))

Models

# Models ------------------------------------------------------------------

# Auto ARIMA --------------------------------------------------------------

model_spec_arima_no_boost <- arima_reg() %>%
  set_engine(engine = "auto_arima")

wflw_auto_arima <- workflow() %>%
  add_recipe(recipe = recipe_base) %>%
  add_model(model_spec_arima_no_boost)

# NNETAR ------------------------------------------------------------------

model_spec_nnetar <- nnetar_reg(
  mode              = "regression"
  , seasonal_period = "auto"
) %>%
  set_engine("nnetar")

wflw_nnetar <- workflow() %>%
  add_recipe(recipe = recipe_base) %>%
  add_model(model_spec_nnetar)

# TSLM --------------------------------------------------------------------

model_spec_lm <- linear_reg() %>%
  set_engine("lm")

wflw_lm <- workflow() %>%
  add_recipe(recipe = recipe_base) %>%
  add_model(model_spec_lm)

# MARS --------------------------------------------------------------------

model_spec_mars <- mars(mode = "regression") %>%
  set_engine("earth")

wflw_mars <- workflow() %>%
  add_recipe(recipe = recipe_base) %>%
  add_model(model_spec_mars)

Nested Modeltime Tables

nested_modeltime_tbl <- modeltime_nested_fit(
  # Nested Data
  nested_data = nested_data_tbl,
   control = control_nested_fit(
     verbose = TRUE,
     allow_par = FALSE
   ),
  # Add workflows
  wflw_auto_arima,
  wflw_lm,
  wflw_mars,
  wflw_nnetar
)
nested_modeltime_tbl <- nested_modeltime_tbl[!is.na(nested_modeltime_tbl$package),]

Model Accuracy

nested_modeltime_tbl %>%
  extract_nested_test_accuracy() %>%
  filter(!is.na(package)) %>%
  knitr::kable()
package .model_id .model_desc .type mae mape mase smape rmse rsq
healthyR.data 1 ARIMA Test 0.5769847 124.36143 0.6396925 123.96472 0.7642366 0.0832545
healthyR.data 2 LM Test 0.6061236 163.32109 0.6719984 115.23968 0.7695681 0.0001498
healthyR.data 3 NULL NA NA NA NA NA NA NA
healthyR.data 4 NNAR Test 0.6714347 98.32367 0.7444076 184.90127 0.9036788 0.0096728
healthyR 1 ARIMA Test 0.7573535 108.88179 0.8635908 174.23504 0.8794500 0.0358217
healthyR 2 LM Test 0.7598488 97.47604 0.8664361 176.40347 0.9034257 0.0020769
healthyR 3 NULL NA NA NA NA NA NA NA
healthyR 4 NNAR Test 0.7296528 97.02221 0.8320044 158.46589 0.8645295 0.1008504
healthyR.ts 1 ARIMA Test 0.8112921 101.62354 0.7162523 185.76745 1.0666797 0.0023942
healthyR.ts 2 LM Test 0.9509663 160.14107 0.8395642 151.79828 1.2116293 0.0479050
healthyR.ts 3 NULL NA NA NA NA NA NA NA
healthyR.ts 4 NNAR Test 0.8162980 100.41061 0.7206717 182.60687 1.0723619 0.0002309
healthyverse 1 ARIMA Test 0.6272108 156.19947 1.1864329 80.80956 0.7710406 0.0323739
healthyverse 2 LM Test 0.5966446 168.36353 1.1286139 76.28560 0.7130334 0.0098079
healthyverse 3 NULL NA NA NA NA NA NA NA
healthyverse 4 NNAR Test 0.6790585 111.71195 1.2845081 93.42693 0.8710909 0.0212466
healthyR.ai 1 ARIMA Test 0.6525775 97.29772 0.7357182 158.20166 0.7903203 0.0175863
healthyR.ai 2 LM Test 0.6362037 101.95698 0.7172583 142.65486 0.7692139 0.0005527
healthyR.ai 3 NULL NA NA NA NA NA NA NA
healthyR.ai 4 NNAR Test 0.6075822 105.72005 0.6849902 127.88472 0.7380746 0.0295722
TidyDensity 1 ARIMA Test 0.4820946 104.22188 0.9710372 104.89697 0.6358710 0.0005904
TidyDensity 2 LM Test 0.6082978 161.05586 1.2252364 107.63689 0.7942561 0.0492374
TidyDensity 3 NULL NA NA NA NA NA NA NA
TidyDensity 4 NNAR Test 0.4658467 83.79059 0.9383106 120.14523 0.5818016 0.0220583
tidyAML 1 ARIMA Test 0.7283439 93.16584 0.7577400 127.21022 0.9315918 0.0000458
tidyAML 2 LM Test 0.5870505 114.43073 0.6107439 79.80988 0.7796806 0.1245822
tidyAML 3 NULL NA NA NA NA NA NA NA
tidyAML 4 NNAR Test 0.6425159 102.56781 0.6684479 106.88044 0.8031043 0.1680441
RandomWalker 1 ARIMA Test 1.3667432 173.64741 0.7362712 148.87312 1.5993081 0.0207203
RandomWalker 2 LM Test 1.2898234 117.12425 0.6948342 189.76518 1.4220087 0.0088204
RandomWalker 3 NULL NA NA NA NA NA NA NA
RandomWalker 4 NNAR Test 1.4106495 158.83986 0.7599238 167.23582 1.5882704 0.0000310

Plot Models

nested_modeltime_tbl %>%
  extract_nested_test_forecast() %>%
  group_by(package) %>%
  plot_modeltime_forecast(
    .interactive = FALSE,
    .conf_interval_show  = FALSE,
    .facet_scales = "free"
  ) +
  theme_minimal() +
  theme(legend.position = "bottom")

Best Model

best_nested_modeltime_tbl <- nested_modeltime_tbl %>%
  modeltime_nested_select_best(
    metric = "rmse",
    minimize = TRUE,
    filter_test_forecasts = TRUE
  )

best_nested_modeltime_tbl %>%
  extract_nested_best_model_report()
## # Nested Modeltime Table
## 

## # A tibble: 8 × 10
##   package      .model_id .model_desc .type   mae  mape  mase smape  rmse     rsq
##   <fct>            <int> <chr>       <chr> <dbl> <dbl> <dbl> <dbl> <dbl>   <dbl>
## 1 healthyR.da…         1 ARIMA       Test  0.577 124.  0.640 124.  0.764 0.0833 
## 2 healthyR             4 NNAR        Test  0.730  97.0 0.832 158.  0.865 0.101  
## 3 healthyR.ts          1 ARIMA       Test  0.811 102.  0.716 186.  1.07  0.00239
## 4 healthyverse         2 LM          Test  0.597 168.  1.13   76.3 0.713 0.00981
## 5 healthyR.ai          4 NNAR        Test  0.608 106.  0.685 128.  0.738 0.0296 
## 6 TidyDensity          4 NNAR        Test  0.466  83.8 0.938 120.  0.582 0.0221 
## 7 tidyAML              2 LM          Test  0.587 114.  0.611  79.8 0.780 0.125  
## 8 RandomWalker         2 LM          Test  1.29  117.  0.695 190.  1.42  0.00882
best_nested_modeltime_tbl %>%
  extract_nested_test_forecast() %>%
  #filter(!is.na(.model_id)) %>%
  group_by(package) %>%
  plot_modeltime_forecast(
    .interactive = FALSE,
    .conf_interval_alpha = 0.2,
    .facet_scales = "free"
  ) +
  theme_minimal() +
  theme(legend.position = "bottom")

Refitting and Future Forecast

Now that we have the best models, we can make our future forecasts.

nested_modeltime_refit_tbl <- best_nested_modeltime_tbl %>%
    modeltime_nested_refit(
        control = control_nested_refit(verbose = TRUE)
    )
nested_modeltime_refit_tbl
## # Nested Modeltime Table
## 

## # A tibble: 8 × 5
##   package       .actual_data .future_data .splits           .modeltime_tables 
##   <fct>         <list>       <list>       <list>            <list>            
## 1 healthyR.data <tibble>     <tibble>     <split [1630|28]> <mdl_tm_t [1 × 5]>
## 2 healthyR      <tibble>     <tibble>     <split [1624|28]> <mdl_tm_t [1 × 5]>
## 3 healthyR.ts   <tibble>     <tibble>     <split [1568|28]> <mdl_tm_t [1 × 5]>
## 4 healthyverse  <tibble>     <tibble>     <split [1538|28]> <mdl_tm_t [1 × 5]>
## 5 healthyR.ai   <tibble>     <tibble>     <split [1363|28]> <mdl_tm_t [1 × 5]>
## 6 TidyDensity   <tibble>     <tibble>     <split [1214|28]> <mdl_tm_t [1 × 5]>
## 7 tidyAML       <tibble>     <tibble>     <split [822|28]>  <mdl_tm_t [1 × 5]>
## 8 RandomWalker  <tibble>     <tibble>     <split [244|28]>  <mdl_tm_t [1 × 5]>
nested_modeltime_refit_tbl %>%
  extract_nested_future_forecast() %>%
  mutate(across(.value:.conf_hi, .fns = ~ standard_inv_vec(
    x    = .,
    mean = std_mean,
    sd   = std_sd
  )$standard_inverse_value)) %>%
  mutate(across(.value:.conf_hi, .fns = ~ liiv(
    x = .,
    limit_lower = limit_lower,
    limit_upper = limit_upper,
    offset      = offset
  )$rescaled_v)) %>%
  group_by(package) %>%
  plot_modeltime_forecast(
    .interactive = FALSE,
    .conf_interval_alpha = 0.2,
    .facet_scales = "free"
  ) +
  theme_minimal() +
  theme(legend.position = "bottom")