Today, give a try to Techtonique web app, a tool designed to help you make informed, data-driven decisions using Mathematics, Statistics, Machine Learning, and Data Visualization. Here is a tutorial with audio, video, code, and slides: https://moudiki2.gumroad.com/l/nrhgb
Hi everyone, best wishes for 2025!
I just got this preprint paper rejected by the International Journal of Forecasting (IJF) despite a benchmark on over 30,000 time series (code from the paper in R and Python available in this post). The method described in the preprint paper, despite being simple (of course, it’s always simple after implementing the idea), is performing on par or much better than the state of the art (which may certainly frustrate some great minds, I get it), as you’ll see below.
So, how do you go from first round reviews like:
- “The comparison with other conformal prediction methods is performed only on simulated data, not on any real-world data at all.”: among the 275 time series from the first submission, 240 were real-world data. See https://github.com/Techtonique/datasets/blob/main/time_series/univariate/250datasets/250timeseries.txt for the list of time series, and https://github.com/Techtonique/datasets/blob/main/time_series/univariate/250datasets/250datasets_characteristics.R for their characteristics. And the proferssor said “at all”.
- “So the authors should demonstrate the merit of their method on a more standard dataset, such as the M4”: see next paragraph for more details.
- Reviewer 1: “I thank the author(s) for the work. It is great to see how […] Conformal Prediction methods grow[s], especially in challenging tasks such as time series forecasting. I strongly appreciate the use of a big data set for the benchmark and that the code is shared. I also appreciate that 2 forecasting models and 5 conformalization procedures are compared (the one using KDE, the one using surrogate, the one using bootstrap, and the state of the art ACI and AgACI)”. Remark: the initial big data set contained 250 time series, and the final data in the second submission’s set contained over 30,000 time series (including M3 and M5 competition data).
- Reviewer 2: “The paper is well-written and clearly structured”.
To a rejection saying things such as:
- About point 2., and after trying to demonstrate the merits on M3 and M5 competition data in submission 2: “The paper shows a factorial application of too many variants to too many datasets which make it hard to follow”. Ok, may look messy, but is there really such a thing as “too many datasets” for proving a point? (No) If so, why not asking to trim down?
- I used “doesn’t” instead of “does not”: this can be modified at edition. Why are we discussing (along with a Grammarly link I was sent :o) this in such length and over 8 months, as if it really mattered?
- I used the term “calibrated residuals”: one reviewer suggested “calibratION residuals” instead while another suggested calling them just “residuals”, such a distraction, what do I do?
- I used the term “predictive simulation”: what should I call it then and why does it really matter? I used simulation of future outcomes indeed, see page 12 of the preprint paper (again, IMHO, a pure distraction)
- “The forecasting community strongly benefits from new approaches and experiments on how to quantify uncertainty, that is why I appreciate the author’s contribution.” Hmm… Okay then…
- “can only accept a limited number of them, which make substantial contributions to the science and practice of forecasting”: knock-out punch.
I’m definitely not the type to whine or cry foul (this is a battle-tested sentence), but I’m curious. Do you see any coherence in the last 2 paragraphs, or am I losing my mind? (No) One thing that was asked and that I’ll address (and I guess it’ll make sense) is why not training the models on the whole training set at the end of my conformal prediction algorithm? Because I want to avoid data leakage, and I also want to use the most contemporaneous data for forecasting.
Interested in seeing the method from the paper in action more directly?
- See this other post, which basically contains one-liner codes for conformalizing R packages such as
forecast
. - See this interactive dashboard.
- Execute the Python and R code of the paper, available in this post (note: takes looong hours to execute).
On a brighter note, a stable version of www.techtonique.net has now been released. A tutorial on how to use it is available https://moudiki2.gumroad.com/l/nrhgb.
Contents of the post
- 1 - M3 competition (R code), 3003 time series
- 2 - M5 competition (Python code), 42840 time series aggregated by item (3049 items)
- 3 - 250 datasets (R code), 240 real-world, 10 synthetic
- 4 - 25 additional synthetic datasets (R code)
Benchmarking errors in the examples below are measured by:
- Coverage rate: the percentage of future values that are within the prediction intervals, for 80% and 95% prediction intervals
- Winkler score: the length of the prediction intervals, penalized by every time the true future value is outside the interval (see https://www.otexts.com/fpp3/distaccuracy.html#winkler-score for more details). The lower the score, the better the method.
Plus, splitconformal
denotes the method described in the paper.
Conformalized predictive simulations for univariate time series¶
1 - M3 competition (R code), 3003 time series¶
1 - 0 - Import packages¶
!pip install rpy2
%load_ext rpy2.ipython
%%R
utils::install.packages(c('foreach', 'forecast', 'fpp', 'fpp2', 'remotes', 'Mcomp'),
repos="https://cran.r-project.org")
remotes::install_github("Techtonique/ahead")
remotes::install_github("thierrymoudiki/simulatetimeseries")
suppressWarnings(library(datasets))
suppressWarnings(library(forecast))
suppressWarnings(library(fpp2))
suppressWarnings(library(ahead))
suppressWarnings(library(Mcomp))
%%R
remotes::install_github("herbps10/AdaptiveConformal", force=TRUE)
suppressWarnings(library(AdaptiveConformal))
%%R
remotes::install_github("thierrymoudiki/misc")
suppressWarnings(library(misc))
%%R
print(length(M3))
print(length(M3[[1000]]$x))
print(length(M3[[1000]]$xx))
print(length(M3[[100]]$x))
print(length(M3[[100]]$xx))
[1] 3003 [1] 44 [1] 8 [1] 14 [1] 6
1 - 1 - Functions and data set¶
%%R
winkler_score <- function(obj, actual, level = 95) {
alpha <- 1 - level / 100
lt <- obj$lower
ut <- obj$upper
n_points <- length(actual)
stopifnot((n_points == length(lt)) && (n_points == length(ut)))
diff_lt <- lt - actual
diff_bounds <- ut - lt
diff_ut <- actual - ut
score <-
diff_bounds + (2 / alpha) * (pmax(diff_lt, 0) + pmax(diff_ut, 0))
return(mean(score))
}
# moving block bootstrap
mbb2 <- function(r,
n,
b,
seed = 123,
return_indices = FALSE)
{
n_obs <- dim(r)[1]
n_series <- dim(r)[2]
b <- floor(min(max(3L, b), n_obs - 1L))
if(n >= n_obs)
stop("forecasting horizon must be < number of observations")
n <- min(n_obs, n)
set.seed(seed) # important for base::sample below
r_bt <- matrix(NA, nrow = n_obs, ncol = dim(r)[2]) # local vector for a bootstrap replication
#cat("n_obs", n_obs, "\n")
#cat("b", b, "\n")
for (i in 1:ceiling(n_obs/b)) {
#cat("i: ", i, "----- \n")
endpoint <- sample(b:n_obs, size = 1)
#cat("endpoint", endpoint, "\n")
try(r_bt[(i - 1)*b + 1:b, ] <- r[endpoint - (b:1) + 1, ],
silent = TRUE)
}
tmp <- matrix(r_bt[(1:n), ], nrow = n, ncol = n_series)
if(return_indices == FALSE)
{
return(tmp)
} else {
return(arrayInd(match(tmp, r), .dim = dim(r))[1:n, 1])
}
}
mbb2 <- memoise::memoise(mbb2)
# split data set
split_dataset <- function(x,
split_prob = 0.8,
transformation=c("none",
"boxcox",
"diff",
"diffboxcox"))
{
transformation <- match.arg(transformation)
if (identical(transformation, "boxcox"))
{
x <- forecast::BoxCox(x, lambda = "auto")
}
if (identical(transformation, "diff"))
{
x <- diff(x)
}
if (identical(transformation, "diffboxcox"))
{
x <- diff(forecast::BoxCox(x, lambda = "auto"))
}
freq_x <- frequency(x)
n <- floor(split_prob*length(x))
half_n <- floor(n/2)
x_train <- ts(x[1:half_n],
start=start(x),
frequency = freq_x)
x_calib <- ts(x[(half_n + 1):n],
start=tsp(x_train)[2] + 1 / freq_x,
frequency = freq_x)
x_test <- ts(x[(n + 1):length(x)],
start=tsp(x_calib)[2] + 1 / freq_x,
frequency = freq_x)
res <- vector("list", 4)
res$x <- x
res$x_train <- x_train
res$x_calib <- x_calib
res$x_test <- x_test
return(res)
}
split_dataset <- memoise::memoise(split_dataset)
# forecasting function
forecast_function <- function(x,
method = c("theta",
"dynrm",
"snaive"),
split_prob = 0.8,
block_size = 5,
B = 250,
level = 95,
seed=123)
{
obj_ts <- split_dataset(x, split_prob=split_prob)
method <- match.arg(method)
freq_x <- frequency(obj_ts$x)
fcast_func <- switch(method,
dynrm = ahead::dynrmf,
theta = forecast::thetaf,
snaive = forecast::snaive)
# calibration
obj <- fcast_func(obj_ts$x_train,
h=length(obj_ts$x_calib)) # train on training set predict on calibration set
calibrated_resids <- obj_ts$x_calib - obj$mean # obtain calibrated residuals
obj_fcast <- fcast_func(obj_ts$x_calib,
h=length(obj_ts$x_test)) # train on calibration set
sims <- ts(sapply(1:B, function(i) mbb2(matrix(calibrated_resids,
ncol = 1),
n=length(obj_ts$x_test),
b=block_size,
seed=i+seed*100)),
start = start(obj_ts$x_test),
frequency = frequency(obj_ts$x_test))
preds <- obj_fcast$mean + sims
obj_fcast2 <- list()
obj_fcast2$level <- level
obj_fcast2$x <- obj_ts$x_calib
start_preds <- start(obj_fcast$mean)
obj_fcast2$mean <- ts(rowMeans(preds),
start = start_preds,
frequency = freq_x)
obj_fcast2$upper <- ts(apply(preds, 1, function(x)
stats::quantile(x, probs = 1 - (1 - level / 100) / 2)),
start = start_preds,
frequency = freq_x)
obj_fcast2$lower <- ts(apply(preds, 1, function(x)
stats::quantile(x, probs = (1 - level / 100) / 2)),
start = start_preds,
frequency = freq_x)
obj_fcast2$method <- method
class(obj_fcast2) <- "forecast"
return(obj_fcast2)
}
compute_errors <- function(obj, preds)
{
res <- vector("list", 8)
true <- obj$mean
names(res) <- c("coverage", "winkler",
"ME", "RMSE", "MAE",
"MPE", "MAPE", "MASE")
res$coverage <- mean(true > obj$lower & true < obj$upper)*100
res$winkler <- winkler_score(obj, actual=true)
res$ME <- mean(true - preds)
res$RMSE <- sqrt(mean((true - preds)^2))
res$MAE <- mean(abs(true - preds))
res$MPE <- mean((true - preds)/true)
res$MAPE <- mean(abs(true - preds)/true)
res$MASE <- mean(abs(true - preds))/mean(abs(true - mean(true)))
return(res)
}
%%R
all_datasets <- lapply(M3, function(s) ts(c(s$x, s$xx),
start=start(s$x),
frequency=frequency(s$x)))
names(all_datasets) <- names(M3)
%%R
library("AdaptiveConformal")
library("ahead")
library("simulatetimeseries")
library("foreach")
library("forecast")
%%R
conformal_methods <- c("splitconformal", "AgACI", "SAOCP", "SF-OGD")
metrics <- c("coverage", "winkler",
"ME", "RMSE", "MAE",
"MPE", "MAPE", "MASE")
# will contain results for each time series
params_grid <- expand.grid(conformal_methods, metrics)
colnames(params_grid) <- c("conformal_method", "metric")
params_grid <- misc::sort_df(params_grid, by="conformal_method", decreasing = FALSE)
params_grid <- cbind(params_grid, value=NA)
rownames(params_grid) <- NULL
print(params_grid)
conformal_method metric value 1 splitconformal coverage NA 2 splitconformal winkler NA 3 splitconformal ME NA 4 splitconformal RMSE NA 5 splitconformal MAE NA 6 splitconformal MPE NA 7 splitconformal MAPE NA 8 splitconformal MASE NA 9 AgACI coverage NA 10 AgACI winkler NA 11 AgACI ME NA 12 AgACI RMSE NA 13 AgACI MAE NA 14 AgACI MPE NA 15 AgACI MAPE NA 16 AgACI MASE NA 17 SAOCP coverage NA 18 SAOCP winkler NA 19 SAOCP ME NA 20 SAOCP RMSE NA 21 SAOCP MAE NA 22 SAOCP MPE NA 23 SAOCP MAPE NA 24 SAOCP MASE NA 25 SF-OGD coverage NA 26 SF-OGD winkler NA 27 SF-OGD ME NA 28 SF-OGD RMSE NA 29 SF-OGD MAE NA 30 SF-OGD MPE NA 31 SF-OGD MAPE NA 32 SF-OGD MASE NA
%%R
results <- vector("list", length(all_datasets))
names(results) <- names(all_datasets)
for (i in 1:length(all_datasets))
{
results[[i]] <- params_grid
}
%%R
print(results[[1]])
conformal_method metric value 1 splitconformal coverage NA 2 splitconformal winkler NA 3 splitconformal ME NA 4 splitconformal RMSE NA 5 splitconformal MAE NA 6 splitconformal MPE NA 7 splitconformal MAPE NA 8 splitconformal MASE NA 9 AgACI coverage NA 10 AgACI winkler NA 11 AgACI ME NA 12 AgACI RMSE NA 13 AgACI MAE NA 14 AgACI MPE NA 15 AgACI MAPE NA 16 AgACI MASE NA 17 SAOCP coverage NA 18 SAOCP winkler NA 19 SAOCP ME NA 20 SAOCP RMSE NA 21 SAOCP MAE NA 22 SAOCP MPE NA 23 SAOCP MAPE NA 24 SAOCP MASE NA 25 SF-OGD coverage NA 26 SF-OGD winkler NA 27 SF-OGD ME NA 28 SF-OGD RMSE NA 29 SF-OGD MAE NA 30 SF-OGD MPE NA 31 SF-OGD MAPE NA 32 SF-OGD MASE NA
1 - 2 - main loops¶
%%R
all_datasets[[1000]]
Qtr1 Qtr2 Qtr3 Qtr4 1980 4381.5 4107.5 3959.0 4117.5 1981 4182.5 4559.5 4652.0 4487.0 1982 4475.5 4472.0 4215.0 4282.0 1983 4424.5 4395.5 4466.5 4565.5 1984 4841.0 4645.0 4904.5 4980.5 1985 4953.5 4951.5 5021.5 5073.5 1986 5119.0 5120.5 5181.5 5071.0 1987 5188.5 5162.5 5511.0 5594.5 1988 5239.5 5800.5 5694.0 5884.0 1989 5841.0 6226.0 6268.5 6262.5 1990 6290.0 6621.5 6662.5 6745.5 1991 6722.0 6509.5 6523.0 6633.5 1992 7003.5 6702.0 7023.5 6970.0
%%R
(nb_iter_datasets <- length(all_datasets))
pb <- txtProgressBar(min = 0,
max = nb_iter_datasets, #nb_iter_datasets,
style = 3)
start_time <- proc.time()[3]
for (i in 1:nb_iter_datasets) # loop levels and methods
{
y <- all_datasets[[i]]
splitted_ts <- simulatetimeseries::splitts(y = y,
split_prob = 0.8)
y_train <- splitted_ts$training
y_test <- splitted_ts$testing
idx_row <- 1 # start filling results[[i]] at row
for (j in 1:nrow(results[[i]]))
{
seed_i_j<- 100*i+300*j
set.seed(seed_i_j)
conformal_method <- as.character(results[[i]]$conformal_method[j])
if (conformal_method == "splitconformal")
{
obj <- forecast_function(y)
result_accuracy <- compute_errors(obj, y_test)
results[[i]][idx_row, 3] <- result_accuracy$coverage
results[[i]][idx_row + 1, 3] <- result_accuracy$winkler
results[[i]][idx_row + 2, 3] <- result_accuracy$ME
results[[i]][idx_row + 3, 3] <- result_accuracy$RMSE
results[[i]][idx_row + 4, 3] <- result_accuracy$MAE
results[[i]][idx_row + 5, 3] <- result_accuracy$MPE
results[[i]][idx_row + 6, 3] <- result_accuracy$MAPE
results[[i]][idx_row + 7, 3] <- result_accuracy$MASE
}
if (conformal_method %in% c("AgACI", "SAOCP", "SF-OGD"))
{
idx_method <- switch(conformal_method,
"AgACI" = 0,
"SAOCP" = 8,
"SF-OGD" = 16)
obj <- forecast::thetaf(y_train, h=length(y_test)
, level = 95L) # the function AdaptiveConformal::aci seems to be broken: for obs1, lower=mean=upper
result_accuracy <- compute_errors(obj, y_test)
preds <- obj$mean
start_time <- proc.time()[3]
result_ac <- AdaptiveConformal::aci(as.vector(y_test),
as.vector(preds),
method = conformal_method,
alpha = 0.95)
elapsed <- proc.time()[3] - start_time
result_ac$lower <- result_ac$intervals[, 1]
result_ac$upper <- result_ac$intervals[, 2]
results[[i]][idx_row + 8 + idx_method, 3] <- mean((y_test >= result_ac$lower)*(y_test <= result_ac$upper))*100
results[[i]][idx_row + 9 + idx_method, 3] <- winkler_score(result_ac,
actual=y_test,
level = 95L)
results[[i]][idx_row + 10 + idx_method, 3] <- result_accuracy$ME
results[[i]][idx_row + 11 + idx_method, 3] <- result_accuracy$RMSE
results[[i]][idx_row + 12 + idx_method, 3] <- result_accuracy$MAE
results[[i]][idx_row + 13 + idx_method, 3] <- result_accuracy$MPE
results[[i]][idx_row + 14 + idx_method, 3] <- result_accuracy$MAPE
results[[i]][idx_row + 15 + idx_method, 3] <- result_accuracy$MASE
}
}
utils::setTxtProgressBar(pb, i)
}
print(proc.time()[3] - start_time)
close(pb)
|======================================================================| 100%elapsed 0.026
%%R
saveRDS(results, "results_M3_coverages_accuracy_20241031.rds")
%%R
results[[900]]
conformal_method metric value 1 splitconformal coverage 100.00000000 2 splitconformal winkler 981.84974777 3 splitconformal ME 559.58561941 4 splitconformal RMSE 593.74425710 5 splitconformal MAE 559.58561941 6 splitconformal MPE 0.09915813 7 splitconformal MAPE 0.09915813 8 splitconformal MASE 11.57573873 9 AgACI coverage 86.66666667 10 AgACI winkler 1770.04184551 11 AgACI ME -115.63456132 12 AgACI RMSE 234.42706737 13 AgACI MAE 206.06445835 14 AgACI MPE -0.02318314 15 AgACI MAPE 0.04146758 16 AgACI MASE 8.86251472 17 SAOCP coverage 0.00000000 18 SAOCP winkler 8126.43890773 19 SAOCP ME -115.63456132 20 SAOCP RMSE 234.42706737 21 SAOCP MAE 206.06445835 22 SAOCP MPE -0.02318314 23 SAOCP MAPE 0.04146758 24 SAOCP MASE 8.86251472 25 SF-OGD coverage 0.00000000 26 SF-OGD winkler 8241.16623572 27 SF-OGD ME -115.63456132 28 SF-OGD RMSE 234.42706737 29 SF-OGD MAE 206.06445835 30 SF-OGD MPE -0.02318314 31 SF-OGD MAPE 0.04146758 32 SF-OGD MASE 8.86251472
%%R
names(results)[2005]
[1] "N2005"
%%R
utils::install.packages(c("dplyr", "forecast"), repos = "https://cran.r-project.org")
library(dplyr)
library(forecast)
%%R
# Use foreach to iterate and combine data frames with an identifying column
combined_results <- foreach::foreach(name = names(results), .combine = dplyr::bind_rows) %dopar% {
type <- M3[[name]]$type
period <- M3[[name]]$period
results[[name]] %>%
mutate(series_name = name,
type = type,
period = period)
}
%%R
print(head(combined_results))
print(tail(combined_results))
conformal_method metric value series_name type period 1 splitconformal coverage 100.00000000 N0001 MICRO YEARLY 2 splitconformal winkler 961.37125000 N0001 MICRO YEARLY 3 splitconformal ME -451.78614069 N0001 MICRO YEARLY 4 splitconformal RMSE 503.17233162 N0001 MICRO YEARLY 5 splitconformal MAE 451.78614069 N0001 MICRO YEARLY 6 splitconformal MPE -0.05761112 N0001 MICRO YEARLY conformal_method metric value series_name type period 96091 SF-OGD ME 292.1919670 N3003 OTHER OTHER 96092 SF-OGD RMSE 331.0231842 N3003 OTHER OTHER 96093 SF-OGD MAE 292.1919670 N3003 OTHER OTHER 96094 SF-OGD MPE 0.0753467 N3003 OTHER OTHER 96095 SF-OGD MAPE 0.0753467 N3003 OTHER OTHER 96096 SF-OGD MASE 5.1971807 N3003 OTHER OTHER
%%R
library(ggplot2)
# Filter the data to only include rows where metric is 'coverage'
df_coverage <- combined_results %>% filter(metric == 'coverage')
# Boxplot
ggplot(df_coverage, aes(x = conformal_method, y = value)) +
geom_boxplot(fill = "lightgray") +
labs(title = "Distribution of Coverage rate for 3003 time series by Conformal Method",
x = "Conformal Method",
y = "Coverage") +
theme_minimal()
%%R
# Winkler score, the lower the better
df_winkler <- combined_results %>% filter(metric == 'winkler')
# Boxplot
ggplot(df_winkler, aes(x = conformal_method, y = log(value))) +
geom_boxplot(fill = "lightgray") +
labs(title = "Distribution of log(Winkler score) for 3003 time series by Conformal Method",
x = "Conformal Method",
y = "Winkler score") +
theme_minimal()
%%R
# Filter the data to only include rows where metric is 'coverage'
df_RMSE <- combined_results %>% filter(metric == 'RMSE')
# Boxplot
ggplot(df_RMSE, aes(x = conformal_method, y = log(value))) +
geom_boxplot(fill = "lightgray") +
labs(title = "Distribution of log(RMSE) for 3003 time series by Conformal Method",
x = "Conformal Method",
y = "RMSE") +
theme_minimal()
The point is really uncertainty in this context, i.e coverage rate and Winkler score. Not RMSE.
%%R
saveRDS(combined_results, "combined_results_M3_coverages_accuracy_20241031.rds")
%%R
# Assuming 'combined_results' is the data frame you loaded from the RDS file
average_coverage <- combined_results %>%
group_by(conformal_method, period) %>%
summarise(average_coverage = mean(value[metric == "coverage"]))
average_coverage
`summarise()` has grouped output by 'conformal_method'. You can override using the `.groups` argument. # A tibble: 16 × 3 # Groups: conformal_method [4] conformal_method period average_coverage <fct> <chr> <dbl> 1 splitconformal MONTHLY 100 2 splitconformal OTHER 100 3 splitconformal QUARTERLY 100 4 splitconformal YEARLY 100 5 AgACI MONTHLY 72.4 6 AgACI OTHER 48.4 7 AgACI QUARTERLY 52.2 8 AgACI YEARLY 31.8 9 SAOCP MONTHLY 0.880 10 SAOCP OTHER 1.26 11 SAOCP QUARTERLY 0.275 12 SAOCP YEARLY 0.109 13 SF-OGD MONTHLY 0 14 SF-OGD OTHER 0.0547 15 SF-OGD QUARTERLY 0 16 SF-OGD YEARLY 0
%%R
# Assuming 'combined_results' is the data frame you loaded from the RDS file
# Winkler score, the lower the better
average_winkler <- combined_results %>%
group_by(conformal_method, period) %>%
summarise(average_winkler = mean(value[metric == "winkler"]))
average_winkler
`summarise()` has grouped output by 'conformal_method'. You can override using the `.groups` argument. # A tibble: 16 × 3 # Groups: conformal_method [4] conformal_method period average_winkler <fct> <chr> <dbl> 1 splitconformal MONTHLY 2748. 2 splitconformal OTHER 1174. 3 splitconformal QUARTERLY 1663. 4 splitconformal YEARLY 1735. 5 AgACI MONTHLY 5369. 6 AgACI OTHER 2238. 7 AgACI QUARTERLY 5848. 8 AgACI YEARLY 14569. 9 SAOCP MONTHLY 25397. 10 SAOCP OTHER 12282. 11 SAOCP QUARTERLY 21957. 12 SAOCP YEARLY 41459. 13 SF-OGD MONTHLY 25570. 14 SF-OGD OTHER 12401. 15 SF-OGD QUARTERLY 22036. 16 SF-OGD YEARLY 41505.
%%R
# Assuming 'combined_results' is the data frame you loaded from the RDS file
average_RMSE <- combined_results %>%
group_by(conformal_method, period) %>%
summarise(average_RMSE = mean(value[metric == "RMSE"]))
average_RMSE
`summarise()` has grouped output by 'conformal_method'. You can override using the `.groups` argument. # A tibble: 16 × 3 # Groups: conformal_method [4] conformal_method period average_RMSE <fct> <chr> <dbl> 1 splitconformal MONTHLY 1194. 2 splitconformal OTHER 668. 3 splitconformal QUARTERLY 1129. 4 splitconformal YEARLY 1662. 5 AgACI MONTHLY 780. 6 AgACI OTHER 360. 7 AgACI QUARTERLY 649. 8 AgACI YEARLY 1183. 9 SAOCP MONTHLY 780. 10 SAOCP OTHER 360. 11 SAOCP QUARTERLY 649. 12 SAOCP YEARLY 1183. 13 SF-OGD MONTHLY 780. 14 SF-OGD OTHER 360. 15 SF-OGD QUARTERLY 649. 16 SF-OGD YEARLY 1183.
Again, the point is really uncertainty in this context, i.e coverage rate and Winkler score. Not RMSE.
%%R
utils::install.packages("knitr")
utils::install.packages("kableExtra")
%%R
library(knitr)
library(kableExtra)
%%R
# Assuming 'average_coverage' is your data frame
kable(average_coverage, format = "latex", booktabs = TRUE,
caption = "Average Coverage by Method and Period") %>%
kable_styling(latex_options = c("striped", "scale_down"))
\begin{table} \centering \caption{Average Coverage by Method and Period} \centering \resizebox{\ifdim\width>\linewidth\linewidth\else\width\fi}{!}{ \begin{tabular}[t]{llr} \toprule conformal\_method & period & average\_coverage\\ \midrule \cellcolor{gray!10}{splitconformal} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{100.0000000}\\ splitconformal & OTHER & 100.0000000\\ \cellcolor{gray!10}{splitconformal} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{100.0000000}\\ splitconformal & YEARLY & 100.0000000\\ \cellcolor{gray!10}{AgACI} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{72.4303909}\\ \addlinespace AgACI & OTHER & 48.3811720\\ \cellcolor{gray!10}{AgACI} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{52.1629623}\\ AgACI & YEARLY & 31.8191214\\ \cellcolor{gray!10}{SAOCP} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{0.8799117}\\ SAOCP & OTHER & 1.2609469\\ \addlinespace \cellcolor{gray!10}{SAOCP} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{0.2752630}\\ SAOCP & YEARLY & 0.1085271\\ \cellcolor{gray!10}{SF-OGD} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{0.0000000}\\ SF-OGD & OTHER & 0.0547345\\ \cellcolor{gray!10}{SF-OGD} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{0.0000000}\\ \addlinespace SF-OGD & YEARLY & 0.0000000\\ \bottomrule \end{tabular}} \end{table}
%%R
# Assuming 'average_winkler' is your data frame
kable(average_winkler, format = "latex", booktabs = TRUE,
caption = "Average Winkler Score by Method and Period") %>%
kable_styling(latex_options = c("striped", "scale_down"))
\begin{table} \centering \caption{Average Winkler Score by Method and Period} \centering \resizebox{\ifdim\width>\linewidth\linewidth\else\width\fi}{!}{ \begin{tabular}[t]{llr} \toprule conformal\_method & period & average\_winkler\\ \midrule \cellcolor{gray!10}{splitconformal} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{2748.174}\\ splitconformal & OTHER & 1174.329\\ \cellcolor{gray!10}{splitconformal} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{1663.088}\\ splitconformal & YEARLY & 1735.325\\ \cellcolor{gray!10}{AgACI} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{5368.826}\\ \addlinespace AgACI & OTHER & 2237.696\\ \cellcolor{gray!10}{AgACI} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{5847.555}\\ AgACI & YEARLY & 14568.552\\ \cellcolor{gray!10}{SAOCP} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{25396.600}\\ SAOCP & OTHER & 12282.197\\ \addlinespace \cellcolor{gray!10}{SAOCP} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{21956.867}\\ SAOCP & YEARLY & 41459.081\\ \cellcolor{gray!10}{SF-OGD} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{25569.669}\\ SF-OGD & OTHER & 12401.179\\ \cellcolor{gray!10}{SF-OGD} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{22035.548}\\ \addlinespace SF-OGD & YEARLY & 41504.670\\ \bottomrule \end{tabular}} \end{table}
%%R
# Assuming 'average_RMSE' is your data frame
kable(average_RMSE, format = "latex", booktabs = TRUE,
caption = "Average RMSE by Method and Period") %>%
kable_styling(latex_options = c("striped", "scale_down"))
\begin{table} \centering \caption{Average RMSE by Method and Period} \centering \resizebox{\ifdim\width>\linewidth\linewidth\else\width\fi}{!}{ \begin{tabular}[t]{llr} \toprule conformal\_method & period & average\_RMSE\\ \midrule \cellcolor{gray!10}{splitconformal} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{1193.5822}\\ splitconformal & OTHER & 667.5194\\ \cellcolor{gray!10}{splitconformal} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{1128.5092}\\ splitconformal & YEARLY & 1662.1212\\ \cellcolor{gray!10}{AgACI} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{779.9480}\\ \addlinespace AgACI & OTHER & 359.7805\\ \cellcolor{gray!10}{AgACI} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{649.2999}\\ AgACI & YEARLY & 1182.6598\\ \cellcolor{gray!10}{SAOCP} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{779.9480}\\ SAOCP & OTHER & 359.7805\\ \addlinespace \cellcolor{gray!10}{SAOCP} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{649.2999}\\ SAOCP & YEARLY & 1182.6598\\ \cellcolor{gray!10}{SF-OGD} & \cellcolor{gray!10}{MONTHLY} & \cellcolor{gray!10}{779.9480}\\ SF-OGD & OTHER & 359.7805\\ \cellcolor{gray!10}{SF-OGD} & \cellcolor{gray!10}{QUARTERLY} & \cellcolor{gray!10}{649.2999}\\ \addlinespace SF-OGD & YEARLY & 1182.6598\\ \bottomrule \end{tabular}} \end{table}
2 - M5 competition (Python code), 42840 time series aggregated by item (3049 items)¶
2 - 1 - Loading packages¶
!pip install nnetsauce xgboost lightgbm numpy pandas scikit-learn
import nnetsauce as ns
import lightgbm as lgb
import xgboost as xgb
import numpy as np
import pandas as pd
from sklearn.ensemble import GradientBoostingRegressor
2 - 2 - Useful functions¶
def calculate_coverage(lower_pred, upper_pred, y_true):
"""Calculate coverage of the prediction intervals."""
within_bounds = np.logical_and(lower_pred <= y_true, y_true <= upper_pred)
return np.mean(within_bounds)
def calculate_winkler_score(lower_pred, upper_pred, y_true, alpha=0.05):
"""Calculate Winkler score for predictions."""
penalty = 2*np.maximum(lower_pred - y_true, 0)/alpha
penalty += 2*np.maximum(y_true - upper_pred, 0)/alpha
scores = (upper_pred - lower_pred) + penalty
return np.mean(scores)
2 - 3 Loading data ¶
Sales Training Data¶
There are initially 42840 time series in the M5 competition. They're aggregated here by item.
df = pd.read_csv("https://raw.githubusercontent.com/Techtonique/datasets/refs/heads/main/time_series/univariate/m5-forecasting-uncertainty-sales-per-item.csv")
df.head()
item_id | d_1 | d_2 | d_3 | d_4 | d_5 | d_6 | d_7 | d_8 | d_9 | ... | d_1904 | d_1905 | d_1906 | d_1907 | d_1908 | d_1909 | d_1910 | d_1911 | d_1912 | d_1913 | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0 | FOODS_1_001 | 6 | 6 | 4 | 6 | 7 | 18 | 10 | 4 | 11 | ... | 4 | 4 | 30 | 7 | 5 | 3 | 6 | 2 | 16 | 6 |
1 | FOODS_1_002 | 4 | 5 | 7 | 4 | 3 | 4 | 1 | 7 | 2 | ... | 5 | 9 | 4 | 1 | 3 | 5 | 5 | 3 | 3 | 1 |
2 | FOODS_1_003 | 14 | 8 | 3 | 6 | 3 | 8 | 13 | 10 | 11 | ... | 7 | 3 | 5 | 6 | 3 | 4 | 4 | 3 | 11 | 5 |
3 | FOODS_1_004 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | ... | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
4 | FOODS_1_005 | 34 | 32 | 13 | 20 | 10 | 21 | 18 | 20 | 25 | ... | 16 | 14 | 14 | 18 | 18 | 27 | 12 | 15 | 38 | 9 |
5 rows × 1914 columns
print(df.describe())
d_1 d_2 d_3 d_4 d_5 d_6 d_7 d_8 d_9 \ count 3049.00 3049.00 3049.00 3049.00 3049.00 3049.00 3049.00 3049.00 3049.00 mean 10.70 10.41 7.80 8.33 6.28 9.58 9.19 12.44 10.74 std 40.83 42.11 27.32 33.27 23.33 35.77 37.81 51.89 44.53 min 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 25% 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 50% 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 75% 9.00 9.00 6.00 7.00 5.00 8.00 7.00 10.00 9.00 max 1345.00 1534.00 757.00 1196.00 749.00 1064.00 1187.00 1745.00 1367.00 d_10 ... d_1904 d_1905 d_1906 d_1907 d_1908 d_1909 d_1910 \ count 3049.00 ... 3049.00 3049.00 3049.00 3049.00 3049.00 3049.00 3049.00 mean 8.39 ... 13.71 15.86 16.94 12.48 12.32 11.59 11.49 std 28.00 ... 27.06 31.44 32.45 23.56 22.79 20.87 21.28 min 0.00 ... 0.00 0.00 0.00 0.00 0.00 0.00 0.00 25% 0.00 ... 3.00 3.00 4.00 2.00 2.00 2.00 2.00 50% 0.00 ... 7.00 8.00 8.00 6.00 6.00 6.00 6.00 75% 7.00 ... 14.00 17.00 17.00 14.00 13.00 12.00 12.00 max 783.00 ... 672.00 832.00 789.00 486.00 434.00 425.00 422.00 d_1911 d_1912 d_1913 count 3049.00 3049.00 3049.00 mean 13.29 16.06 16.33 std 25.15 31.22 28.47 min 0.00 0.00 0.00 25% 3.00 3.00 4.00 50% 7.00 8.00 8.00 75% 14.00 17.00 18.00 max 629.00 793.00 592.00 [8 rows x 1913 columns]
print(df.info())
<class 'pandas.core.frame.DataFrame'> RangeIndex: 3049 entries, 0 to 3048 Columns: 1914 entries, item_id to d_1913 dtypes: int64(1913), object(1) memory usage: 44.5+ MB None
2 - 4 Forecasting¶
from time import time
2 - 4 - 1 Functions¶
def forecast(df, idx=0, model="xgb", pi_method= "quantile",
pct_train=0.9, **kwargs):
assert pct_train > 0.6, "must have pct_train > 0.6"
x = df.iloc[idx, 1:].diff().dropna().values.astype(np.float64)
n_points = len(x)
x_train = x[:int(n_points*pct_train)].ravel()
x_test = x[int(n_points*pct_train):].ravel()
lags = 1 # number of lags to consider
h = len(x_test)
if pi_method == "conformal":
if model == "xgb":
regr = ns.MTS(obj=xgb.XGBRegressor(
tree_method="hist", **kwargs),
n_hidden_features=0,
type_pi="scp2-kde", # split conformal prediction with KDE simulation
replications=250, # number of simulations
lags=lags,
show_progress=False,
verbose=0)
elif model == "gb":
regr = ns.MTS(obj=GradientBoostingRegressor(**kwargs),
n_hidden_features=0,
type_pi="scp2-kde", # split conformal prediction with KDE simulation
replications=250, # number of simulations
lags=lags,
show_progress=False,
verbose=0)
elif model == "lgb":
regr = ns.MTS(obj=lgb.LGBMRegressor(verbosity=-1, **kwargs),
n_hidden_features=0,
type_pi="scp2-kde", # split conformal prediction with KDE simulation
replications=250, # number of simulations
lags=lags,
show_progress=False,
verbose=0)
else:
raise NotImplementedError
start = time()
res = regr.fit(x_train).predict(h = h)
time_taken = time() - start
lower_pred = res.lower.values.ravel()
upper_pred = res.upper.values.ravel()
y_true = x_test
elif pi_method == "quantile":
if model == "xgb":
bounds =[]
for i, alpha in enumerate([0.025, 0.975]):
regr = ns.MTS(obj=xgb.XGBRegressor(objective="reg:quantileerror",
tree_method="hist",
quantile_alpha=alpha, **kwargs),
n_hidden_features=0,
lags=lags,
show_progress=False,
verbose=0)
start = time()
regr.fit(x_train)
time_taken = time() - start
bounds.append(regr.predict(h = h))
elif model == "gb":
bounds =[]
for i, alpha in enumerate([0.025, 0.975]):
regr = ns.MTS(obj=GradientBoostingRegressor(loss="quantile",
alpha=alpha, **kwargs),
n_hidden_features=0,
lags=lags,
show_progress=False,
verbose=0)
start = time()
regr.fit(x_train)
bounds.append(regr.predict(h = h))
time_taken = time() - start
elif model == "lgb":
bounds =[]
for i, alpha in enumerate([0.025, 0.975]):
regr = ns.MTS(obj=lgb.LGBMRegressor(objective = 'quantile',
alpha = alpha,
verbosity=-1, **kwargs),
n_hidden_features=0,
lags=lags,
show_progress=False,
verbose=0)
start = time()
regr.fit(x_train)
bounds.append(regr.predict(h = h))
time_taken = time() - start
else:
raise NotImplementedError
lower_pred = bounds[0].values.ravel()
upper_pred = bounds[1].values.ravel()
y_true = x_test
return calculate_coverage(lower_pred, upper_pred, y_true), calculate_winkler_score(lower_pred, upper_pred, y_true), time_taken
2 - 4 - 2 loop¶
res = []
from tqdm import tqdm
Parallel
from time import time
model_pi_methods = [(model, pi_method) for model in ["xgb", "gb", "lgb"] for pi_method in ["quantile", "conformal"]]
for model, pi_method in model_pi_methods:
print(model, pi_method)
xgb quantile xgb conformal gb quantile gb conformal lgb quantile lgb conformal
from joblib import Parallel, delayed
from tqdm import tqdm
from time import time
def process_forecast(store_idx):
result = []
for model, pi_method in model_pi_methods:
try:
ans = forecast(df, idx=store_idx, model=model, pi_method=pi_method)
result.append([model, pi_method, ans[0], ans[1], ans[2]])
except Exception as e:
continue
return result
start = time()
res = Parallel(n_jobs=-1)(delayed(process_forecast)(store_idx) for store_idx in tqdm(range(df.shape[0])))
end = time()
print(end - start)
res = [item for sublist in res for item in sublist]
res_array = np.array(res)
res_df = pd.DataFrame(res_array, columns=["model", "pi_method",
"coverage", "winkler",
"time"], index=None)
res_df
model | pi_method | coverage | winkler | time | |
---|---|---|---|---|---|
0 | xgb | quantile | 0.7916666666666666 | 51.1210212608518 | 0.4013369083404541 |
1 | xgb | conformal | 0.9270833333333334 | 39.81039934883048 | 28.924641132354736 |
2 | gb | quantile | 0.75 | 57.3768650098391 | 3.0318901538848877 |
3 | gb | conformal | 0.9166666666666666 | 40.109831397718715 | 19.903746843338013 |
4 | lgb | quantile | 0.7864583333333334 | 51.34335123406788 | 3.0518510341644287 |
... | ... | ... | ... | ... | ... |
17816 | xgb | conformal | 0.921875 | 7.745386069078937 | 10.091049909591675 |
17817 | gb | quantile | 0.7552083333333334 | 16.191994712662865 | 0.7770967483520508 |
17818 | gb | conformal | 0.921875 | 7.7454295687221775 | 6.986394166946411 |
17819 | lgb | quantile | 0.4947916666666667 | 35.219043821425906 | 0.3016550540924072 |
17820 | lgb | conformal | 0.9010416666666666 | 8.79169911751688 | 5.0931642055511475 |
17821 rows × 5 columns
res_df.to_csv("2024_10_22_m5_sales_uncertainty_prediction_results_local.csv")
2 - 4 - 3 Formatting¶
2 - 4 - 4 basic info¶
import pandas as pd
import numpy as np
results_local = pd.read_csv("2024_10_22_m5_sales_uncertainty_prediction_results_local.csv")
results_local['coverage'] = results_local['coverage'].astype(np.float64)
results_local['winkler'] = results_local['winkler'].astype(np.float64)
results_local['time'] = results_local['time'].astype(np.float64)
display(results_local.describe())
Unnamed: 0 | coverage | winkler | time | |
---|---|---|---|---|
count | 17821.00 | 17821.00 | 17821.00 | 17821.00 |
mean | 8910.00 | 0.76 | 63.09 | 8.79 |
std | 5144.62 | 0.25 | 98.74 | 10.32 |
min | 0.00 | 0.00 | 2.08 | 0.12 |
25% | 4455.00 | 0.70 | 21.62 | 1.12 |
50% | 8910.00 | 0.83 | 37.22 | 4.57 |
75% | 13365.00 | 0.92 | 70.44 | 13.57 |
max | 17820.00 | 1.00 | 7270.32 | 152.02 |
2 - 4 - 5 Tables and graphics¶
df = pd.read_csv("2024_10_22_m5_sales_uncertainty_prediction_results_local.csv")
df['log_error_rate'] = np.log(1 - df['coverage'])
df['log_winkler'] = np.log(df['winkler'])
df['log_time'] = np.log(df['time'])
df_grouped = df.groupby(['model', 'pi_method'])[['coverage', 'winkler', 'time']].agg(['min', 'median', 'max'])
df_grouped.transpose()
model | gb | lgb | xgb | ||||
---|---|---|---|---|---|---|---|
pi_method | conformal | quantile | conformal | quantile | conformal | quantile | |
coverage | min | 0.00 | 0.03 | 0.00 | 0.05 | 0.00 | 0.29 |
median | 0.89 | 0.81 | 0.89 | 0.75 | 0.90 | 0.79 | |
max | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | |
winkler | min | 2.08 | 2.08 | 5.77 | 5.00 | 5.54 | 4.78 |
median | 35.66 | 34.44 | 36.00 | 42.34 | 35.43 | 38.08 | |
max | 1781.88 | 7270.32 | 1272.90 | 1304.69 | 1781.88 | 1553.96 | |
time | min | 2.45 | 0.78 | 2.46 | 0.30 | 2.30 | 0.12 |
median | 12.66 | 1.23 | 15.13 | 3.10 | 12.59 | 0.22 | |
max | 152.02 | 13.71 | 149.08 | 130.01 | 63.82 | 7.96 |
latex_table = df_grouped.transpose().applymap(lambda x: f"{x:.2f}" if isinstance(x, float) else x).to_latex()
print(latex_table)
\begin{tabular}{llllllll} \toprule & model & \multicolumn{2}{r}{gb} & \multicolumn{2}{r}{lgb} & \multicolumn{2}{r}{xgb} \\ & pi_method & conformal & quantile & conformal & quantile & conformal & quantile \\ \midrule \multirow[t]{3}{*}{coverage} & min & 0.00 & 0.03 & 0.00 & 0.05 & 0.00 & 0.29 \\ & median & 0.89 & 0.81 & 0.89 & 0.75 & 0.90 & 0.79 \\ & max & 1.00 & 1.00 & 1.00 & 1.00 & 1.00 & 1.00 \\ \cline{1-8} \multirow[t]{3}{*}{winkler} & min & 2.08 & 2.08 & 5.77 & 5.00 & 5.54 & 4.78 \\ & median & 35.66 & 34.44 & 36.00 & 42.34 & 35.43 & 38.08 \\ & max & 1781.88 & 7270.32 & 1272.90 & 1304.69 & 1781.88 & 1553.96 \\ \cline{1-8} \multirow[t]{3}{*}{time} & min & 2.45 & 0.78 & 2.46 & 0.30 & 2.30 & 0.12 \\ & median & 12.66 & 1.23 & 15.13 & 3.10 & 12.59 & 0.22 \\ & max & 152.02 & 13.71 & 149.08 & 130.01 & 63.82 & 7.96 \\ \cline{1-8} \bottomrule \end{tabular}
!pip install matplotlib seaborn
import matplotlib.pyplot as plt
import seaborn as sns
# Coverage plot
plt.figure(figsize=(8, 4))
sns.boxplot(x='model', y='log_error_rate', hue='pi_method', data=df)
plt.title('Log error rate per Model and PI Method')
plt.xlabel('Model')
plt.ylabel('Log error rate')
plt.xticks(rotation=45, ha='right')
plt.legend(title='PI Method')
plt.tight_layout()
plt.show()
# Winkler plot
plt.figure(figsize=(8, 4))
sns.boxplot(x='model', y='log_winkler', hue='pi_method', data=df)
plt.title('Log Winkler Score per Model and PI Method')
plt.xlabel('Model')
plt.ylabel('Log Winkler Score')
plt.xticks(rotation=45, ha='right')
plt.legend(title='PI Method')
plt.tight_layout()
plt.show()
# Time plot
plt.figure(figsize=(8, 4))
sns.boxplot(x='model', y='log_time', hue='pi_method', data=df)
plt.title('Time per Model and PI Method')
plt.xlabel('Model')
plt.ylabel('Log Time in Log(seconds)')
plt.xticks(rotation=45, ha='right')
plt.legend(title='PI Method')
plt.tight_layout()
plt.show()
Conformalizing requires splitting the data and fitting twice, so is logically slower.
3 - 250 various time series (210 real-world, 40 synthetic)¶
250 time series, 240 real-world, 10 synthetic. See https://github.com/Techtonique/datasets/blob/main/time_series/univariate/250datasets/250timeseries.txt for the list of time series, and https://github.com/Techtonique/datasets/blob/main/time_series/univariate/250datasets/250datasets_characteristics.R for their characteristics.
!pip install rpy2
%load_ext rpy2.ipython
%%R
utils::install.packages(c('forecast', 'fpp', 'fpp2', 'remotes'))
remotes::install_github("Techtonique/ahead")
remotes::install_github("thierrymoudiki/simulatetimeseries")
## ----"6-twofiftydatasets", echo=FALSE, cache=TRUE, message=FALSE, warning=FALSE-------------------------------------
utils::install.packages(c("astsa",
"datasets",
"expsmooth",
"fma",
"forecast",
"fpp",
"fpp2",
"MASS",
"remotes",
"reshape2",
"tswge"), repos="https://cran.r-project.org", quiet=TRUE)
remotes::install_github("thierrymoudiki/simulatetimeseries")
remotes::install_github("herbps10/AdaptiveConformal")
remotes::install_github("Techtonique/ahead")
install.packages("foreach", repos="https://cran.r-project.org")
install.packages("forecast", repos="https://cran.r-project.org")
suppressWarnings(library(datasets))
suppressWarnings(library(forecast))
suppressWarnings(library(fpp2))
suppressWarnings(library(ahead))
suppressWarnings(library(simulatetimeseries))
## ----"1-foursynthplot", echo=FALSE, cache=TRUE, message=FALSE, warning=FALSE, fig.cap="4 synthetic data sets (among 47)"----
suppressWarnings(library(datasets))
suppressWarnings(library(forecast))
suppressWarnings(library(fpp2))
suppressWarnings(library(ahead))
suppressWarnings(library(simulatetimeseries))
%%R
# /!\ Despite package name, these are mostly real-world time series (210), differenced once
# (see https://github.com/Techtonique/datasets/blob/main/time_series/univariate/250datasets/250timeseries.txt)
all_datasets <- simulatetimeseries::get_data_1() # easier is to download https://github.com/Techtonique/datasets/blob/main/time_series/univariate/250datasets/all_datasets.rds
row_names <- names(all_datasets)
visualizing a few examples among the 250 time series
%%R
print(length(all_datasets))
par(mfrow=c(2, 2))
plot(all_datasets[[1]])
plot(all_datasets[[10]])
plot(all_datasets[[5]])
plot(all_datasets[[50]])
[1] 250
%%R
par(mfrow=c(2, 2))
plot(all_datasets[[2]])
plot(all_datasets[[11]])
plot(all_datasets[[9]])
plot(all_datasets[[51]])
%%R
# EXAMPLE ON A DATA SET CONTAINING 250 TIME SERIES ------------------------------------------------------------
col_names <- c("thetaf_0", "dynrmf_0",
"thetaf_kde", "dynrmf_kde",
"thetaf_boot", "dynrmf_boot",
"thetaf_surr", "dynrmf_surr")
n_datasets <- length(all_datasets)
n_methods <- length(col_names)
results_winkler_score <- results_coverage_rate <- matrix(0, nrow=n_datasets, ncol=n_methods)
rownames(results_winkler_score) <- row_names
colnames(results_winkler_score) <- col_names
rownames(results_coverage_rate) <- row_names
colnames(results_coverage_rate) <- col_names
results_winkler_score <- as.data.frame(results_winkler_score)
results_coverage_rate <- as.data.frame(results_coverage_rate)
params <- vector("list", n_methods)
names(params) <- col_names
level <- 95
pct_train <- 0.9
pct_calibration <- 0.5
types_sim <- c("kde", "boot", "surr")
library("foreach")
pb <- txtProgressBar(min = 0,
max = n_datasets,
style = 3)
progress <- function(n)
utils::setTxtProgressBar(pb, n)
opts <- list(progress = progress)
| | 0%
%%R
idx_dataset <- NULL
pb <- utils::txtProgressBar(min = 0, max = n_datasets, style = 3)
for(idx_dataset in 1:n_datasets) {
selected_data <- all_datasets[[idx_dataset]]
# no conformalization
fit_obj <- try(ahead::fitforecast(selected_data, conformalize = 0, pct_train = pct_train,
pct_calibration=pct_calibration,
method = "dynrmf"), silent = TRUE)
if (!inherits(fit_obj, "try-error"))
{
results_winkler_score[, "dynrmf_0"][idx_dataset] <- fit_obj$winkler_score
results_coverage_rate[, "dynrmf_0"][idx_dataset] <- fit_obj$coverage
} else {
results_winkler_score[, "dynrmf_0"][idx_dataset] <- NA
results_coverage_rate[, "dynrmf_0"][idx_dataset] <- NA
}
fit_obj <- try(ahead::fitforecast(selected_data, conformalize = 0, pct_train = pct_train,
pct_calibration=pct_calibration,
method = "thetaf"), silent = TRUE)
if (!inherits(fit_obj, "try-error"))
{
results_winkler_score[, "thetaf_0"][idx_dataset] <- fit_obj$winkler_score
results_coverage_rate[, "thetaf_0"][idx_dataset] <- fit_obj$coverage
} else {
results_winkler_score[, "thetaf_0"][idx_dataset] <- NA
results_coverage_rate[, "thetaf_0"][idx_dataset] <- NA
}
# conformalization
for (type_sim in types_sim){
fit_obj <- try(ahead::fitforecast(selected_data, conformalize = 1,
pct_train = pct_train,
pct_calibration=pct_calibration,
method = "dynrmf", type_sim = type_sim), silent = TRUE)
if (!inherits(fit_obj, "try-error"))
{
results_winkler_score[, paste0('dynrmf', '_', type_sim)][idx_dataset] <- fit_obj$winkler_score
results_coverage_rate[, paste0('dynrmf', '_', type_sim)][idx_dataset] <- fit_obj$coverage #abs(fit_obj$coverage/level - 1)*100
} else {
results_winkler_score[, paste0('dynrmf', '_', type_sim)][idx_dataset] <- NA
results_coverage_rate[, paste0('dynrmf', '_', type_sim)][idx_dataset] <- NA
}
fit_obj <- try(ahead::fitforecast(selected_data, conformalize = 1,
pct_train = pct_train,
pct_calibration=pct_calibration,
method = "thetaf", type_sim = type_sim), silent = TRUE)
if (!inherits(fit_obj, "try-error"))
{
results_winkler_score[, paste0('thetaf', '_', type_sim)][idx_dataset] <- fit_obj$winkler_score
results_coverage_rate[, paste0('thetaf', '_', type_sim)][idx_dataset] <- fit_obj$coverage #abs(fit_obj$coverage/level - 1)*100
} else {
results_winkler_score[, paste0('thetaf', '_', type_sim)][idx_dataset] <- NA
results_coverage_rate[, paste0('thetaf', '_', type_sim)][idx_dataset] <- NA
}
}
utils::setTxtProgressBar(pb, idx_dataset)
}
close(pb)
saveRDS(object = results_winkler_score, file = "results_winkler_score.rds")
saveRDS(object = results_coverage_rate, file = "results_coverage_rate.rds")
|======================================================================| 100%
De plus : Il y a eu 50 avis ou plus (utilisez warnings() pour voir les 50 premiers)
%%R
# Expected coverage rate: 95%
# methods ending with "_0" are not conformalized
# all the other methods are conformalized
coverage_ci <- t(apply(results_coverage_rate, 2, function(x) c(mean(x, na.rm = TRUE),
quantile(x, c(0.025, 0.975), na.rm = TRUE))))
colnames(coverage_ci) <- c("mean", "lower", "upper")
coverage_ci <- as.data.frame(coverage_ci)
coverage_ci$method <- rownames(coverage_ci)
coverage_ci
mean lower upper method thetaf_0 88.83283 31.57895 100 thetaf_0 dynrmf_0 87.69836 34.27419 100 dynrmf_0 thetaf_kde 88.22848 28.38095 100 thetaf_kde dynrmf_kde 93.77326 63.22967 100 dynrmf_kde thetaf_boot 82.48538 15.77303 100 thetaf_boot dynrmf_boot 89.86451 33.33333 100 dynrmf_boot thetaf_surr 84.88912 26.66667 100 thetaf_surr dynrmf_surr 91.56125 56.22222 100 dynrmf_surr
%%R
# Winkler score, the lower the better
# methods ending with "_0" are not conformalized
# all the other methods are conformalized
winkler_ci <- t(apply(results_winkler_score, 2, function(x) c(mean(x, na.rm = TRUE),
quantile(x, c(0.025, 0.975), na.rm = TRUE))))
colnames(winkler_ci) <- c("mean", "lower", "upper")
winkler_ci <- as.data.frame(winkler_ci)
winkler_ci$method <- rownames(winkler_ci)
winkler_ci
mean lower upper method thetaf_0 49775.61 0.3749945 150265.61 thetaf_0 dynrmf_0 21427.87 0.3624831 70254.36 dynrmf_0 thetaf_kde 45347.61 0.3803968 144066.16 thetaf_kde dynrmf_kde 20929.91 0.3775642 62999.15 dynrmf_kde thetaf_boot 48121.65 0.3480542 144554.24 thetaf_boot dynrmf_boot 22728.10 0.3433424 61013.21 dynrmf_boot thetaf_surr 48790.68 0.3499667 144421.17 thetaf_surr dynrmf_surr 22467.88 0.3436461 61741.29 dynrmf_surr
4 - Synthetic data (25 time series)¶
%%R
# EXAMPLE ON A SYNTHETIC DATA SET ------------------------------------------------------------
## ----echo=FALSE, cache=FALSE, message=FALSE, warning=FALSE----------------------------------------------------------
winkler_score <- function(obj, actual, level = 95) {
alpha <- 1 - level / 100
lt <- obj$lower
ut <- obj$upper
n_points <- length(actual)
stopifnot((n_points == length(lt)) && (n_points == length(ut)))
diff_lt <- lt - actual
diff_bounds <- ut - lt
diff_ut <- actual - ut
score <-
diff_bounds + (2 / alpha) * (pmax(diff_lt, 0) + pmax(diff_ut, 0))
return(mean(score))
}
## ----"7-aci-agci", echo=FALSE, cache=TRUE, message=FALSE, warning=FALSE---------------------------------------------
library("AdaptiveConformal")
library("ahead")
library("simulatetimeseries")
library("foreach")
library("forecast")
B <- 100
params_psi <- params_theta <- c(0.1, 0.8, 0.9, 0.95, 0.99)
levels <- c(80, 95)
fcast_methods <- c("thetaf", "dynrmf")
conformal_methods <- c("splitconformal", "AgACI", "SAOCP", "SF-OGD")
(params_grid <- expand.grid(params_psi, params_theta,
levels, fcast_methods,
conformal_methods))
colnames(params_grid) <- c("psi", "theta",
"level",
"fcast_method",
"conformal_method")
params_grid$fcast_method <- as.vector(params_grid$fcast_method)
params_grid$conformal_method <- as.vector(params_grid$conformal_method)
results <- matrix(0, ncol=B, nrow=nrow(params_grid))
colnames(results) <- paste0("B", seq_len(B))
params_grid <- params_grid2 <- cbind.data.frame(params_grid, results)
nb_iter <- nrow(params_grid)
pb <- txtProgressBar(min = 0,
max = nb_iter,
style = 3)
for (i in 1:nrow(params_grid))
{
for (j in 6:ncol(params_grid))
{
seed_i_j <- 100*i+300*j
y <- simulatetimeseries::simulate_time_series_4(n = 600,
params_grid$psi[i],
params_grid$theta[i],
seed=seed_i_j)
splitted_ts <- simulatetimeseries::splitts(y = y, split_prob = 0.9)
y_train <- splitted_ts$training
y_test <- splitted_ts$testing
if (as.character(params_grid$conformal_method[i]) == "splitconformal")
{
obj <- ahead::fitforecast(y,
conformalize = TRUE,
pct_train = 0.9,
pct_calibration = 0.5,
method = as.character(params_grid$fcast_method[i]),
type_calibration = "splitconformal",
level = params_grid$level[i],
type_sim = "kde",
graph = FALSE
)
params_grid[i, j] <- obj$coverage
params_grid2[i, j] <- obj$winkler_score
}
if (as.character(params_grid$conformal_method[i]) %in% c("AgACI", "SAOCP", "SF-OGD"))
{
obj <- switch(as.character(params_grid$fcast_method[i]),
thetaf = forecast::thetaf(y_train, h=length(y_test)),
dynrmf = ahead::dynrmf(y_train, h=length(y_test)))
preds <- obj$mean
result <- AdaptiveConformal::aci(as.vector(y_test),
as.vector(preds),
method = as.character(params_grid$conformal_method[i]),
alpha = params_grid$level[i]/100)
result$lower <- result$intervals[, 1]
result$upper <- result$intervals[, 2]
params_grid[i, j] <- result$metrics$coverage*100
params_grid2[i, j] <- winkler_score(result, actual=y_test, level = params_grid$level[i])
}
}
utils::setTxtProgressBar(pb, i)
}
close(pb)
saveRDS(params_grid, "params_grid_coverages.rds")
saveRDS(params_grid2, "params_grid_winkler.rds")
4 - 1 Coverage rates for synthetic data¶
%%R
# CONFIDENCE INTERVALS FOR THE SYNTHETIC DATA SET
## ----"11-ag-agci-confint-coverage", echo=FALSE, cache=TRUE, warning=FALSE, message=FALSE----------------------------
utils::install.packages("dplyr", repos = "https://cran.r-project.org")
library("dplyr")
df <- reshape2::melt(params_grid,
id.vars=c("level",
"fcast_method",
"conformal_method"),
measure.vars=paste0("B", seq_len(B)))
df$variable <- NULL
%%R
utils::install.packages("patchwork")
library(patchwork)
%%R
# Create interaction label for x-axis
df$method_combo <- paste(df$fcast_method, df$conformal_method, sep="\n")
# Summary tables for each level
table_80 <- df %>%
filter(level == 80) %>%
group_by(fcast_method, conformal_method) %>%
summarise(
mean = mean(value),
sd = sd(value),
median = median(value),
q25 = quantile(value, 0.25),
q75 = quantile(value, 0.75)
) %>%
arrange(desc(mean))
table_95 <- df %>%
filter(level == 95) %>%
group_by(fcast_method, conformal_method) %>%
summarise(
mean = mean(value),
sd = sd(value),
median = median(value),
q25 = quantile(value, 0.25),
q75 = quantile(value, 0.75)
) %>%
arrange(desc(mean))
# Plot for level 80
p1 <- ggplot(df[df$level == 80,], aes(x=method_combo, y=value)) +
geom_boxplot(fill="lightgray") +
labs(title="Distribution of Coverage Rates by Method (Level = 80)",
x="Forecasting Method + Conformal Method",
y="Value") +
theme_minimal() +
theme(axis.text.x = element_text(angle = 45, hjust = 1))
# Plot for level 95
p2 <- ggplot(df[df$level == 95,], aes(x=method_combo, y=value)) +
geom_boxplot(fill="lightgray") +
labs(title="Distribution of Coverage Rates by Method (Level = 95)",
x="Forecasting Method + Conformal Method",
y="Value") +
theme_minimal() +
theme(axis.text.x = element_text(angle = 45, hjust = 1))
# Display plots one after another using patchwork
library(patchwork)
print(p1 / p2)
`summarise()` has grouped output by 'fcast_method'. You can override using the `.groups` argument. `summarise()` has grouped output by 'fcast_method'. You can override using the `.groups` argument.
%%R
# Print formatted tables
cat("Coverage Rate Summary Statistics for Level 80:\n")
print(kable(table_80, digits = 2))
Coverage Rate Summary Statistics for Level 80: |fcast_method |conformal_method | mean| sd| median| q25| q75| |:------------|:----------------|-----:|----:|------:|-----:|-----:| |dynrmf |splitconformal | 81.40| 7.37| 83.33| 76.67| 86.67| |thetaf |splitconformal | 79.85| 8.50| 81.67| 75.00| 85.00| |dynrmf |AgACI | 77.61| 4.06| 78.33| 75.00| 80.00| |thetaf |AgACI | 77.41| 4.08| 78.33| 75.00| 80.00| |dynrmf |SAOCP | 52.77| 3.76| 53.33| 50.00| 55.00| |thetaf |SAOCP | 51.81| 4.73| 51.67| 50.00| 55.00| |dynrmf |SF-OGD | 1.20| 1.39| 1.67| 0.00| 1.67| |thetaf |SF-OGD | 1.16| 1.38| 0.00| 0.00| 1.67|
%%R
cat("\nCoverage Rate Summary Statistics for Level 95:\n")
print(kable(table_95, digits = 2))
Coverage Rate Summary Statistics for Level 95: |fcast_method |conformal_method | mean| sd| median| q25| q75| |:------------|:----------------|-----:|----:|------:|-----:|-----:| |dynrmf |splitconformal | 95.57| 4.12| 96.67| 93.33| 98.33| |thetaf |splitconformal | 94.38| 4.96| 95.00| 91.67| 98.33| |dynrmf |AgACI | 89.98| 3.02| 90.00| 88.33| 91.67| |thetaf |AgACI | 89.74| 3.12| 90.00| 88.33| 91.67| |dynrmf |SAOCP | 59.56| 3.85| 60.00| 56.67| 61.67| |thetaf |SAOCP | 58.41| 4.91| 58.33| 56.67| 61.67| |dynrmf |SF-OGD | 1.19| 1.39| 1.67| 0.00| 1.67| |thetaf |SF-OGD | 1.17| 1.37| 1.67| 0.00| 1.67|
4 - 2 Winkler scores for synthetic data¶
The lower the better.
%%R
## ----"12-ag-agci-confint-winkler", echo=FALSE, cache=TRUE, warning=FALSE, message=FALSE-----------------------------
df <- reshape2::melt(params_grid2,
id.vars=c("level",
"fcast_method",
"conformal_method"),
measure.vars=paste0("B", seq_len(B)))
df$variable <- NULL
%%R
# Create interaction label for x-axis
df$method_combo <- paste(df$fcast_method, df$conformal_method, sep="\n")
# Summary tables for each level
table_80 <- df %>%
filter(level == 80) %>%
group_by(fcast_method, conformal_method) %>%
summarise(
mean = mean(value),
sd = sd(value),
median = median(value),
q25 = quantile(value, 0.25),
q75 = quantile(value, 0.75)
) %>%
arrange(desc(mean))
table_95 <- df %>%
filter(level == 95) %>%
group_by(fcast_method, conformal_method) %>%
summarise(
mean = mean(value),
sd = sd(value),
median = median(value),
q25 = quantile(value, 0.25),
q75 = quantile(value, 0.75)
) %>%
arrange(desc(mean))
# Plot for level 80
p1 <- ggplot(df[df$level == 80,], aes(x=method_combo, y=value)) +
geom_boxplot(fill="lightgray") +
labs(title="Distribution of Winkler Scores by Method (Level = 80)",
x="Forecasting Method + Conformal Method",
y="Value") +
theme_minimal() +
theme(axis.text.x = element_text(angle = 45, hjust = 1))
# Plot for level 95
p2 <- ggplot(df[df$level == 95,], aes(x=method_combo, y=value)) +
geom_boxplot(fill="lightgray") +
labs(title="Distribution of Winkler Scores by Method (Level = 95)",
x="Forecasting Method + Conformal Method",
y="Value") +
theme_minimal() +
theme(axis.text.x = element_text(angle = 45, hjust = 1))
# Display plots one after another using patchwork
library(patchwork)
print(p1 / p2)
`summarise()` has grouped output by 'fcast_method'. You can override using the `.groups` argument. `summarise()` has grouped output by 'fcast_method'. You can override using the `.groups` argument.
%%R
# Print formatted tables
cat("Winkler Score Summary Statistics for Level 80:\n")
print(kable(table_80, digits = 2))
Winkler Score Summary Statistics for Level 80: |fcast_method |conformal_method | mean| sd| median| q25| q75| |:------------|:----------------|-----:|----:|------:|-----:|-----:| |thetaf |SF-OGD | 47.91| 8.74| 46.39| 42.21| 51.26| |dynrmf |SF-OGD | 46.16| 6.03| 45.57| 42.16| 49.59| |thetaf |SAOCP | 26.23| 5.01| 25.33| 22.90| 28.45| |dynrmf |SAOCP | 24.95| 3.59| 24.61| 22.47| 26.83| |thetaf |AgACI | 21.85| 3.10| 21.53| 19.58| 23.52| |thetaf |splitconformal | 21.16| 3.79| 20.41| 18.82| 22.50| |dynrmf |AgACI | 21.07| 2.49| 20.87| 19.37| 22.55| |dynrmf |splitconformal | 20.28| 2.85| 19.78| 18.53| 21.44|
%%R
# Print formatted tables
# Winkler score, the lower the better
cat("Winkler Score Summary Statistics for Level 95:\n")
print(kable(table_95, digits = 2))
Winkler Score Summary Statistics for Level 95: |fcast_method |conformal_method | mean| sd| median| q25| q75| |:------------|:----------------|------:|-----:|------:|------:|------:| |thetaf |SF-OGD | 191.33| 33.69| 185.45| 169.11| 205.35| |dynrmf |SF-OGD | 183.80| 23.78| 181.53| 168.26| 197.23| |thetaf |SAOCP | 67.82| 16.35| 65.02| 56.87| 74.78| |dynrmf |SAOCP | 63.90| 11.80| 62.66| 55.78| 70.58| |thetaf |AgACI | 32.80| 4.95| 32.20| 29.26| 35.67| |dynrmf |AgACI | 31.82| 4.15| 31.53| 28.83| 34.36| |thetaf |splitconformal | 28.01| 6.01| 26.39| 24.51| 29.46| |dynrmf |splitconformal | 26.56| 4.68| 25.63| 24.05| 27.89|
5 - Session info¶
5 - 1 Python¶
import platform
# Get basic machine information
python_version = platform.python_version()
print("Python Version:", python_version)
Python Version: 3.11.10
import psutil
# CPU Information
cpu_count = psutil.cpu_count(logical=True)
cpu_freq = psutil.cpu_freq()
cpu_usage = psutil.cpu_percent(interval=1)
# Memory Information
virtual_memory = psutil.virtual_memory()
swap_memory = psutil.swap_memory()
# Disk Information
disk_usage = psutil.disk_usage('/')
print(f"CPU Count: {cpu_count}")
print(f"CPU Frequency: {cpu_freq.current} MHz")
CPU Count: 8 CPU Frequency: 1100 MHz
!pip freeze
Python(54508) MallocStackLogging: can't turn off malloc stack logging because it was not enabled.
appnope==0.1.4 asttokens==2.4.1 certifi==2024.12.14 cffi==1.17.1 charset-normalizer==3.4.1 click==8.1.7 comm==0.2.1 contourpy==1.3.1 cycler==0.12.1 debugpy==1.8.1 decorator==5.1.1 executing==2.0.1 fonttools==4.55.3 idna==3.10 ipykernel==6.29.3 ipython==8.22.2 jedi==0.19.1 Jinja2==3.1.5 joblib==1.4.2 jupyter_client==8.6.0 jupyter_core==5.7.1 kiwisolver==1.4.8 lightgbm==4.5.0 MarkupSafe==3.0.2 matplotlib==3.10.0 matplotlib-inline==0.1.6 nest-asyncio==1.6.0 nnetsauce==0.29.5 numpy==2.2.1 packaging==23.2 pandas==2.2.3 parso==0.8.3 patsy==1.0.1 pexpect==4.9.0 pillow==11.1.0 platformdirs==4.2.0 prompt-toolkit==3.0.43 psutil==5.9.8 ptyprocess==0.7.0 pure-eval==0.2.2 pycparser==2.22 Pygments==2.17.2 pyparsing==3.2.1 python-dateutil==2.9.0.post0 pytz==2024.2 pyzmq==25.1.2 requests==2.32.3 rpy2==3.5.17 rtopy==0.1.1 scikit-learn==1.6.0 scipy==1.15.0 seaborn==0.13.2 six==1.16.0 stack-data==0.6.3 statsmodels==0.14.4 threadpoolctl==3.5.0 tornado==6.4 tqdm==4.67.1 traitlets==5.14.1 tzdata==2024.2 tzlocal==5.2 urllib3==2.3.0 wcwidth==0.2.13 xgboost==2.1.3
5 - 2 R¶
%R sessionInfo()
R.version |
ListVector with 14 elements.
|
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---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
platform |
StrVector with 1 elements.
|
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locale |
StrVector with 1 elements.
|
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... | ... | ||||||||||||||||||||
BLAS |
StrVector with 1 elements.
|
||||||||||||||||||||
LAPACK |
StrVector with 1 elements.
|
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LA_version |
StrVector with 1 elements.
|
Conclusion
So, based on these extensive experiments against the state of the art (and assuming the implementations of the state of the art methods are correct, which I’m sure they are, see https://computo.sfds.asso.fr/published-202407-susmann-adaptive-conformal/, and assuming I’m using them well), how cool is this contribution to the science of forecasting? My results are particularly impressive on the 3003 time series from the M3 competition (versus other quite recent conformal prediction methods). On M5 competition data, the method is performing on par with XGBoost, LightGBM, GradientBoostingRegressor quantile regressors. All from 3 prominent package heavyweights on the market. My 2 cents (but I might be wrong): almost nobody likes simplicity in corporate world, and in academia in particular, because they need to justify, somehow, why something is expensive/why they are funded. A bias that fuels complexity (read: complex=”substantial”) for the sake of complexity. Man, IT JUST WORKS. And even more than that, as hopefully demonstrated here with extensive benchmarks.
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