BenchmarkAggr {mlr3benchmark}

Aggregated Benchmark Result Object

Description

An R6 class for aggregated benchmark results.

Details

This class is used to easily carry out and guide analysis of models after aggregating the results after resampling. This can either be constructed using mlr3 objects, for example the result of mlr3::BenchmarkResult⁠$aggregate⁠ or via as_benchmark_aggr, or by passing in a custom dataset of results. Custom datasets must include at the very least, a character column for learner ids, a character column for task ids, and numeric columns for one or more measures.

Currently supported for multiple independent datasets only.

Active bindings

data

(data.table::data.table)
Aggregated data.

learners

(character())
Unique learner names.

tasks

(character())
Unique task names.

measures

(character())
Unique measure names.

nlrns

(integer())
Number of learners.

ntasks

(integer())
Number of tasks.

nmeas

(integer())
Number of measures.

nrow

(integer())
Number of rows.

col_roles

(character())
Column roles, currently cannot be changed after construction.

Methods

Public methods

• BenchmarkAggr$new()

• BenchmarkAggr$print()

• BenchmarkAggr$summary()

• BenchmarkAggr$rank_data()

• BenchmarkAggr$friedman_test()

• BenchmarkAggr$friedman_posthoc()

• BenchmarkAggr$subset()

• BenchmarkAggr$clone()

Method new()

Creates a new instance of this R6 class.

Usage

BenchmarkAggr$new(
  dt,
  task_id = "task_id",
  learner_id = "learner_id",
  independent = TRUE,
  strip_prefix = TRUE,
  ...
)

Arguments

dt

(matrix(1))
' matrix like object coercable to data.table::data.table, should include column names "task_id" and "learner_id", and at least one measure (numeric). If ids are not already factors then coerced internally.

task_id

(character(1))
String specifying name of task id column.

learner_id

(character(1))
String specifying name of learner id column.

independent

(logical(1))
Are tasks independent of one another? Affects which tests can be used for analysis.

strip_prefix

(logical(1))
If TRUE (default) then mlr prefixes, e.g. regr., classif., are automatically stripped from the learner_id.

...

ANY
Additional arguments, currently unused.

Method print()

Prints the internal data via data.table::print.data.table.

Usage

BenchmarkAggr$print(...)

Arguments

...

ANY
Passed to data.table::print.data.table.

Method summary()

Prints the internal data via data.table::print.data.table.

Usage

BenchmarkAggr$summary(...)

Arguments

...

ANY
Passed to data.table::print.data.table.

Method rank_data()

Ranks the aggregated data given some measure.

Usage

BenchmarkAggr$rank_data(meas = NULL, minimize = TRUE, task = NULL, ...)

Arguments

meas

(character(1))
Measure to rank the data against, should be in ⁠$measures⁠. Can be NULL if only one measure in data.

minimize

(logical(1))
Should the measure be minimized? Default is TRUE.

task

(character(1))
If NULL then returns a matrix of ranks where columns are tasks and rows are learners, otherwise returns a one-column matrix of a specified task, should be in ⁠$tasks⁠.

...

ANY ANY
Passed to data.table::frank().

Method friedman_test()

Computes Friedman test over all tasks, assumes datasets are independent.

Usage

BenchmarkAggr$friedman_test(meas = NULL, p.adjust.method = NULL)

Arguments

meas

(character(1))
Measure to rank the data against, should be in ⁠$measures⁠. If no measure is provided then returns a matrix of tests for all measures.

p.adjust.method

(character(1))
Passed to p.adjust if meas = NULL for multiple testing correction. If NULL then no correction applied.

Method friedman_posthoc()

Posthoc Friedman Nemenyi tests. Computed with PMCMRplus::frdAllPairsNemenyiTest. If global ⁠$friedman_test⁠ is non-significant then this is returned and no post-hocs computed. Also returns critical difference

Usage

BenchmarkAggr$friedman_posthoc(
  meas = NULL,
  p.value = 0.05,
  friedman_global = TRUE
)

Arguments

meas

(character(1))
Measure to rank the data against, should be in ⁠$measures⁠. Can be NULL if only one measure in data.

p.value

(numeric(1))
p.value for which the global test will be considered significant.

friedman_global

(logical(1))
Should a friedman global test be performed before conducting the posthoc test? If FALSE, a warning is issued in case the corresponding friedman global test fails instead of an error. Default is TRUE (raises an error if global test fails).

Method subset()

Subsets the data by given tasks or learners. Returns data as data.table::data.table.

Usage

BenchmarkAggr$subset(task = NULL, learner = NULL)

Arguments

task

(character())
Task(s) to subset the data by.

learner

(character())
Learner(s) to subset the data by.

Method clone()

The objects of this class are cloneable with this method.

Usage

BenchmarkAggr$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

References

'r format_bib("demsar_2006")

Examples

# Not restricted to mlr3 objects
df = data.frame(tasks = factor(rep(c("A", "B"), each = 5),
                               levels = c("A", "B")),
                learners = factor(paste0("L", 1:5)),
                RMSE = runif(10), MAE = runif(10))
as_benchmark_aggr(df, task_id = "tasks", learner_id = "learners")

if (requireNamespaces(c("mlr3", "rpart"))) {
  library(mlr3)
  task = tsks(c("boston_housing", "mtcars"))
  learns = lrns(c("regr.featureless", "regr.rpart"))
  bm = benchmark(benchmark_grid(task, learns, rsmp("cv", folds = 2)))

  # coercion
  as_benchmark_aggr(bm)
}