Title:	R6-Based ML Survival Learners for 'mlexperiments'
Version:	0.0.5
Description:	Enhances 'mlexperiments' https://CRAN.R-project.org/package=mlexperiments with additional machine learning ('ML') learners for survival analysis. The package provides R6-based survival learners for the following algorithms: 'glmnet' https://CRAN.R-project.org/package=glmnet, 'ranger' https://CRAN.R-project.org/package=ranger, 'xgboost' https://CRAN.R-project.org/package=xgboost, and 'rpart' https://CRAN.R-project.org/package=rpart. These can be used directly with the 'mlexperiments' R package.
License:	GPL (≥ 3)
URL:	https://github.com/kapsner/mlsurvlrnrs
BugReports:	https://github.com/kapsner/mlsurvlrnrs/issues
Depends:	R (≥ 4.1.0)
Imports:	data.table, kdry, mlexperiments, mllrnrs, R6, stats
Suggests:	glmnet, lintr, mlr3measures, ParBayesianOptimization, quarto, ranger, rpart, splitTools, survival, testthat (≥ 3.0.1), xgboost
VignetteBuilder:	quarto
Config/testthat/edition:	3
Config/testthat/parallel:	false
Date/Publication:	2025-03-03 21:20:02 UTC
Encoding:	UTF-8
SystemRequirements:	Quarto command line tools (https://github.com/quarto-dev/quarto-cli).
RoxygenNote:	7.3.2
NeedsCompilation:	no
Packaged:	2025-03-03 20:46:39 UTC; user
Author:	Lorenz A. Kapsner [cre, aut, cph]
Maintainer:	Lorenz A. Kapsner <lorenz.kapsner@gmail.com>
Repository:	CRAN

R6 Class to construct a Cox proportional hazards survival learner

Description

The LearnerSurvCoxPHCox class is the interface to perform a Cox regression with the survival R package for use with the mlexperiments package.

Details

Can be used with

• mlexperiments::MLCrossValidation

Super class

mlexperiments::MLLearnerBase -> LearnerSurvCoxPHCox

Methods

Public methods

• LearnerSurvCoxPHCox$new()

• LearnerSurvCoxPHCox$clone()

Method new()

Create a new LearnerSurvCoxPHCox object.

Usage

LearnerSurvCoxPHCox$new()

Returns

A new LearnerSurvCoxPHCox R6 object.

Examples

LearnerSurvCoxPHCox$new()

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerSurvCoxPHCox$clone(deep = FALSE)

Arguments

See Also

survival::coxph()

Examples

# survival analysis

dataset <- survival::colon |>
  data.table::as.data.table() |>
  na.omit()
dataset <- dataset[get("etype") == 2, ]

seed <- 123
surv_cols <- c("status", "time", "rx")

feature_cols <- colnames(dataset)[3:(ncol(dataset) - 1)]

split_vector <- splitTools::multi_strata(
  df = dataset[, .SD, .SDcols = surv_cols],
  strategy = "kmeans",
  k = 4
)

train_x <- model.matrix(
  ~ -1 + .,
  dataset[, .SD, .SDcols = setdiff(feature_cols, surv_cols[1:2])]
)
train_y <- survival::Surv(
  event = (dataset[, get("status")] |>
             as.character() |>
             as.integer()),
  time = dataset[, get("time")],
  type = "right"
)

fold_list <- splitTools::create_folds(
  y = split_vector,
  k = 3,
  type = "stratified",
  seed = seed
)


surv_coxph_cox_optimizer <- mlexperiments::MLCrossValidation$new(
  learner = LearnerSurvCoxPHCox$new(),
  fold_list = fold_list,
  ncores = 1L,
  seed = seed
)
surv_coxph_cox_optimizer$performance_metric <- c_index

# set data
surv_coxph_cox_optimizer$set_data(
  x = train_x,
  y = train_y
)

surv_coxph_cox_optimizer$execute()


## ------------------------------------------------
## Method `LearnerSurvCoxPHCox$new`
## ------------------------------------------------

LearnerSurvCoxPHCox$new()

R6 Class to construct a Glmnet survival learner for Cox regression

Description

The LearnerSurvGlmnetCox class is the interface to perform a Cox regression with the glmnet R package for use with the mlexperiments package.

Details

Optimization metric: C-index Can be used with

• mlexperiments::MLTuneParameters

• mlexperiments::MLCrossValidation

• mlexperiments::MLNestedCV

Super class

mlexperiments::MLLearnerBase -> LearnerSurvGlmnetCox

Methods

Public methods

• LearnerSurvGlmnetCox$new()

• LearnerSurvGlmnetCox$clone()

Method new()

Create a new LearnerSurvGlmnetCox object.

Usage

LearnerSurvGlmnetCox$new()

Returns

A new LearnerSurvGlmnetCox R6 object.

Examples

LearnerSurvGlmnetCox$new()

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerSurvGlmnetCox$clone(deep = FALSE)

Arguments

See Also

glmnet::glmnet(), glmnet::cv.glmnet()

Examples

# survival analysis

dataset <- survival::colon |>
  data.table::as.data.table() |>
  na.omit()
dataset <- dataset[get("etype") == 2, ]

seed <- 123
surv_cols <- c("status", "time", "rx")

feature_cols <- colnames(dataset)[3:(ncol(dataset) - 1)]

param_list_glmnet <- expand.grid(
  alpha = seq(0, 1, .2)
)

ncores <- 2L

split_vector <- splitTools::multi_strata(
  df = dataset[, .SD, .SDcols = surv_cols],
  strategy = "kmeans",
  k = 4
)

train_x <- model.matrix(
  ~ -1 + .,
  dataset[, .SD, .SDcols = setdiff(feature_cols, surv_cols[1:2])]
)
train_y <- survival::Surv(
  event = (dataset[, get("status")] |>
             as.character() |>
             as.integer()),
  time = dataset[, get("time")],
  type = "right"
)


fold_list <- splitTools::create_folds(
  y = split_vector,
  k = 3,
  type = "stratified",
  seed = seed
)

surv_glmnet_cox_optimizer <- mlexperiments::MLCrossValidation$new(
  learner = LearnerSurvGlmnetCox$new(),
  fold_list = fold_list,
  ncores = ncores,
  seed = seed
)
surv_glmnet_cox_optimizer$learner_args <- list(
  alpha = 0.8,
  lambda = 0.002
)
surv_glmnet_cox_optimizer$performance_metric <- c_index

# set data
surv_glmnet_cox_optimizer$set_data(
  x = train_x,
  y = train_y
)

surv_glmnet_cox_optimizer$execute()

## ------------------------------------------------
## Method `LearnerSurvGlmnetCox$new`
## ------------------------------------------------

LearnerSurvGlmnetCox$new()

R6 Class to construct a Ranger survival learner for Cox regression

Description

The LearnerSurvRangerCox class is the interface to perform a Cox regression with the ranger R package for use with the mlexperiments package.

Details

Optimization metric: C-index Can be used with

• mlexperiments::MLTuneParameters

• mlexperiments::MLCrossValidation

• mlexperiments::MLNestedCV

Super class

mlexperiments::MLLearnerBase -> LearnerSurvRangerCox

Methods

Public methods

• LearnerSurvRangerCox$new()

• LearnerSurvRangerCox$clone()

Method new()

Create a new LearnerSurvRangerCox object.

Usage

LearnerSurvRangerCox$new()

Returns

A new LearnerSurvRangerCox R6 object.

Examples

LearnerSurvRangerCox$new()

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerSurvRangerCox$clone(deep = FALSE)

Arguments

See Also

ranger::ranger()

Examples

# survival analysis

dataset <- survival::colon |>
  data.table::as.data.table() |>
  na.omit()
dataset <- dataset[get("etype") == 2, ]

seed <- 123
surv_cols <- c("status", "time", "rx")

feature_cols <- colnames(dataset)[3:(ncol(dataset) - 1)]

param_list_ranger <- expand.grid(
  sample.fraction = seq(0.6, 1, .2),
  min.node.size = seq(1, 5, 4),
  mtry = seq(2, 6, 2),
  num.trees = c(5L, 10L),
  max.depth = seq(1, 5, 4)
)

ncores <- 2L

split_vector <- splitTools::multi_strata(
  df = dataset[, .SD, .SDcols = surv_cols],
  strategy = "kmeans",
  k = 4
)

train_x <- model.matrix(
  ~ -1 + .,
  dataset[, .SD, .SDcols = setdiff(feature_cols, surv_cols[1:2])]
)
train_y <- survival::Surv(
  event = (dataset[, get("status")] |>
             as.character() |>
             as.integer()),
  time = dataset[, get("time")],
  type = "right"
)

fold_list <- splitTools::create_folds(
  y = split_vector,
  k = 3,
  type = "stratified",
  seed = seed
)

surv_ranger_cox_optimizer <- mlexperiments::MLCrossValidation$new(
  learner = LearnerSurvRangerCox$new(),
  fold_list = fold_list,
  ncores = ncores,
  seed = seed
)
surv_ranger_cox_optimizer$learner_args <- as.list(
  data.table::data.table(param_list_ranger[1, ], stringsAsFactors = FALSE)
)
surv_ranger_cox_optimizer$performance_metric <- c_index

# set data
surv_ranger_cox_optimizer$set_data(
  x = train_x,
  y = train_y
)

surv_ranger_cox_optimizer$execute()


## ------------------------------------------------
## Method `LearnerSurvRangerCox$new`
## ------------------------------------------------

LearnerSurvRangerCox$new()

LearnerSurvRpartCox R6 class

Description

This learner is a wrapper around rpart::rpart() in order to fit recursive partitioning and regression trees with survival data.

Details

Optimization metric: C-index * Can be used with

• mlexperiments::MLTuneParameters

• mlexperiments::MLCrossValidation

• mlexperiments::MLNestedCV

Implemented methods:

• ⁠$fit⁠ To fit the model.

• ⁠$predict⁠ To predict new data with the model.

• ⁠$cross_validation⁠ To perform a grid search (hyperparameter optimization).

• ⁠$bayesian_scoring_function⁠ To perform a Bayesian hyperparameter optimization.

Parameters that are specified with parameter_grid and / or learner_args are forwarded to rpart's argument control (see rpart::rpart.control() for further details).

Super class

mlexperiments::MLLearnerBase -> LearnerSurvRpartCox

Methods

Public methods

• LearnerSurvRpartCox$new()

• LearnerSurvRpartCox$clone()

Method new()

Create a new LearnerSurvRpartCox object.

Usage

LearnerSurvRpartCox$new()

Details

This learner is a wrapper around rpart::rpart() in order to fit recursive partitioning and regression trees with survival data.

Examples

LearnerSurvRpartCox$new()

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerSurvRpartCox$clone(deep = FALSE)

Arguments

See Also

rpart::rpart(), c_index(), rpart::rpart.control()

rpart::rpart(), c_index(),

Examples

# survival analysis

dataset <- survival::colon |>
  data.table::as.data.table() |>
  na.omit()
dataset <- dataset[get("etype") == 2, ]

seed <- 123
surv_cols <- c("status", "time", "rx")

feature_cols <- colnames(dataset)[3:(ncol(dataset) - 1)]

ncores <- 2L

split_vector <- splitTools::multi_strata(
  df = dataset[, .SD, .SDcols = surv_cols],
  strategy = "kmeans",
  k = 4
)

train_x <- model.matrix(
  ~ -1 + .,
  dataset[, .SD, .SDcols = setdiff(feature_cols, surv_cols[1:2])]
)
train_y <- survival::Surv(
  event = (dataset[, get("status")] |>
             as.character() |>
             as.integer()),
  time = dataset[, get("time")],
  type = "right"
)

fold_list <- splitTools::create_folds(
  y = split_vector,
  k = 3,
  type = "stratified",
  seed = seed
)

surv_rpart_optimizer <- mlexperiments::MLCrossValidation$new(
  learner = LearnerSurvRpartCox$new(),
  fold_list = fold_list,
  ncores = ncores,
  seed = seed
)
surv_rpart_optimizer$learner_args <- list(
  minsplit = 10L,
  maxdepth = 20L,
  cp = 0.03,
  method = "exp"
)
surv_rpart_optimizer$performance_metric <- c_index

# set data
surv_rpart_optimizer$set_data(
  x = train_x,
  y = train_y
)

surv_rpart_optimizer$execute()


## ------------------------------------------------
## Method `LearnerSurvRpartCox$new`
## ------------------------------------------------

LearnerSurvRpartCox$new()

R6 Class to construct a Xgboost survival learner for accelerated failure time models

Description

The LearnerSurvXgboostAft class is the interface to accelerated failure time models with the xgboost R package for use with the mlexperiments package.

Details

Optimization metric: needs to be specified with the learner parameter eval_metric. Can be used with

• mlexperiments::MLTuneParameters

• mlexperiments::MLCrossValidation

• mlexperiments::MLNestedCV

Also see the official xgboost documentation on aft models: https://xgboost.readthedocs.io/en/stable/tutorials/aft_survival_analysis.html

Super classes

mlexperiments::MLLearnerBase -> mllrnrs::LearnerXgboost -> LearnerSurvXgboostAft

Methods

Public methods

• LearnerSurvXgboostAft$new()

• LearnerSurvXgboostAft$clone()

Method new()

Create a new LearnerSurvXgboostAft object.

Usage

LearnerSurvXgboostAft$new(metric_optimization_higher_better)

Arguments

Returns

A new LearnerSurvXgboostAft R6 object.

Examples

LearnerSurvXgboostAft$new(metric_optimization_higher_better = FALSE)

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerSurvXgboostAft$clone(deep = FALSE)

Arguments

See Also

xgboost::xgb.train(), xgboost::xgb.cv()

Examples

# execution time >2.5 sec
# survival analysis

dataset <- survival::colon |>
  data.table::as.data.table() |>
  na.omit()
dataset <- dataset[get("etype") == 2, ]

seed <- 123
surv_cols <- c("status", "time", "rx")

feature_cols <- colnames(dataset)[3:(ncol(dataset) - 1)]

param_list_xgboost <- expand.grid(
  objective = "survival:aft",
  eval_metric = "aft-nloglik",
  subsample = seq(0.6, 1, .2),
  colsample_bytree = seq(0.6, 1, .2),
  min_child_weight = seq(1, 5, 4),
  learning_rate = c(0.1, 0.2),
  max_depth = seq(1, 5, 4)
)
ncores <- 2L

split_vector <- splitTools::multi_strata(
  df = dataset[, .SD, .SDcols = surv_cols],
  strategy = "kmeans",
  k = 4
)

train_x <- model.matrix(
  ~ -1 + .,
  dataset[, .SD, .SDcols = setdiff(feature_cols, surv_cols[1:2])]
)
train_y <- survival::Surv(
  event = (dataset[, get("status")] |>
             as.character() |>
             as.integer()),
  time = dataset[, get("time")],
  type = "right"
)

fold_list <- splitTools::create_folds(
  y = split_vector,
  k = 3,
  type = "stratified",
  seed = seed
)

surv_xgboost_aft_optimizer <- mlexperiments::MLCrossValidation$new(
  learner = LearnerSurvXgboostAft$new(
    metric_optimization_higher_better = FALSE
  ),
  fold_list = fold_list,
  ncores = ncores,
  seed = seed
)
surv_xgboost_aft_optimizer$learner_args <- c(as.list(
  data.table::data.table(param_list_xgboost[1, ], stringsAsFactors = FALSE)
),
nrounds = 45L
)
surv_xgboost_aft_optimizer$performance_metric <- c_index

# set data
surv_xgboost_aft_optimizer$set_data(
  x = train_x,
  y = train_y
)

surv_xgboost_aft_optimizer$execute()



## ------------------------------------------------
## Method `LearnerSurvXgboostAft$new`
## ------------------------------------------------

LearnerSurvXgboostAft$new(metric_optimization_higher_better = FALSE)

R6 Class to construct a Xgboost survival learner for Cox regression

Description

The LearnerSurvXgboostCox class is the interface to perform a Cox regression with the xgboost R package for use with the mlexperiments package.

Details

Optimization metric: needs to be specified with the learner parameter eval_metric. Can be used with

• mlexperiments::MLTuneParameters

• mlexperiments::MLCrossValidation

• mlexperiments::MLNestedCV

Super classes

mlexperiments::MLLearnerBase -> mllrnrs::LearnerXgboost -> LearnerSurvXgboostCox

Methods

Public methods

• LearnerSurvXgboostCox$new()

• LearnerSurvXgboostCox$clone()

Method new()

Create a new LearnerSurvXgboostCox object.

Usage

LearnerSurvXgboostCox$new(metric_optimization_higher_better)

Arguments

Returns

A new LearnerSurvXgboostCox R6 object.

Examples

LearnerSurvXgboostCox$new(metric_optimization_higher_better = FALSE)

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerSurvXgboostCox$clone(deep = FALSE)

Arguments

See Also

xgboost::xgb.train(), xgboost::xgb.cv()

Examples

# execution time >2.5 sec
# survival analysis

dataset <- survival::colon |>
  data.table::as.data.table() |>
  na.omit()
dataset <- dataset[get("etype") == 2, ]

seed <- 123
surv_cols <- c("status", "time", "rx")

feature_cols <- colnames(dataset)[3:(ncol(dataset) - 1)]

param_list_xgboost <- expand.grid(
  objective = "survival:cox",
  eval_metric = "cox-nloglik",
  subsample = seq(0.6, 1, .2),
  colsample_bytree = seq(0.6, 1, .2),
  min_child_weight = seq(1, 5, 4),
  learning_rate = c(0.1, 0.2),
  max_depth = seq(1, 5, 4)
)
ncores <- 2L

split_vector <- splitTools::multi_strata(
  df = dataset[, .SD, .SDcols = surv_cols],
  strategy = "kmeans",
  k = 4
)

train_x <- model.matrix(
  ~ -1 + .,
  dataset[, .SD, .SDcols = setdiff(feature_cols, surv_cols[1:2])]
)
train_y <- survival::Surv(
  event = (dataset[, get("status")] |>
             as.character() |>
             as.integer()),
  time = dataset[, get("time")],
  type = "right"
)

fold_list <- splitTools::create_folds(
  y = split_vector,
  k = 3,
  type = "stratified",
  seed = seed
)

surv_xgboost_cox_optimizer <- mlexperiments::MLCrossValidation$new(
  learner = LearnerSurvXgboostCox$new(
    metric_optimization_higher_better = FALSE
  ),
  fold_list = fold_list,
  ncores = ncores,
  seed = seed
)
surv_xgboost_cox_optimizer$learner_args <- c(as.list(
  data.table::data.table(param_list_xgboost[1, ], stringsAsFactors = FALSE)
),
nrounds = 45L
)
surv_xgboost_cox_optimizer$performance_metric <- c_index

# set data
surv_xgboost_cox_optimizer$set_data(
  x = train_x,
  y = train_y
)

surv_xgboost_cox_optimizer$execute()



## ------------------------------------------------
## Method `LearnerSurvXgboostCox$new`
## ------------------------------------------------

LearnerSurvXgboostCox$new(metric_optimization_higher_better = FALSE)

c_index

Description

Calculate the Harrell's concordance index (C-index)

Usage

c_index(ground_truth, predictions)

Arguments

Details

A wrapper function around glmnet::Cindex() for use with mlexperiments.

See Also

glmnet::Cindex()

Examples

set.seed(123)
gt <- survival::Surv(
  time = rnorm(100, 50, 15),
  event = sample(0:1, 100, TRUE)
)
preds <- rbeta(100, 2, 5)

c_index(gt, preds)