Classification Stochastic Gradient Descent Learner

Stochastic Gradient Descent for learning various linear models. Calls RWeka::make_Weka_classifier() from RWeka.

Initial parameter values

• F:

  • Has only 2 out of 5 original loss functions: 0 = hinge loss (SVM) and 1 = log loss (logistic regression) with 0 (hinge loss) still being the default

  • Reason for change: this learner should only contain loss functions appropriate for classification tasks

Custom mlr3 parameters

• output_debug_info:

  • original id: output-debug-info

• do_not_check_capabilities:

  • original id: do-not-check-capabilities

• num_decimal_places:

  • original id: num-decimal-places

• batch_size:

  • original id: batch-size

• Reason for change: This learner contains changed ids of the following control arguments since their ids contain irregular pattern

Dictionary

This Learner can be instantiated via lrn():

lrn("classif.sgd")

Meta Information

• Task type: “classif”

• Predict Types: “response”, “prob”

• Feature Types: “logical”, “integer”, “numeric”, “factor”, “ordered”

• Required Packages: mlr3, RWeka

Parameters

Id	Type	Default	Levels	Range
subset	untyped	-		-
na.action	untyped	-		-
F	character	0	0, 1	-
L	numeric	0.01		\((-\infty, \infty)\)
R	numeric	1e-04		\((-\infty, \infty)\)
E	integer	500		\((-\infty, \infty)\)
C	numeric	0.001		\((-\infty, \infty)\)
N	logical	-	TRUE, FALSE	-
M	logical	-	TRUE, FALSE	-
S	integer	1		\((-\infty, \infty)\)
output_debug_info	logical	FALSE	TRUE, FALSE	-
do_not_check_capabilities	logical	FALSE	TRUE, FALSE	-
num_decimal_places	integer	2		\([1, \infty)\)
batch_size	integer	100		\([1, \infty)\)
options	untyped	NULL		-

See also

• Dictionary of Learners: mlr3::mlr_learners.

• as.data.table(mlr_learners) for a table of available Learners in the running session (depending on the loaded packages).

• Chapter in the mlr3book: https://mlr3book.mlr-org.com/basics.html#learners

• mlr3learners for a selection of recommended learners.

• mlr3cluster for unsupervised clustering learners.

• mlr3pipelines to combine learners with pre- and postprocessing steps.

• mlr3tuning for tuning of hyperparameters, mlr3tuningspaces for established default tuning spaces.

Author

damirpolat

Super classes

mlr3::Learner -> mlr3::LearnerClassif -> LearnerClassifSGD

Methods

Public methods

• LearnerClassifSGD$new()

• LearnerClassifSGD$clone()

Inherited methods

• mlr3::Learner$base_learner()
• mlr3::Learner$configure()
• mlr3::Learner$encapsulate()
• mlr3::Learner$format()
• mlr3::Learner$help()
• mlr3::Learner$predict()
• mlr3::Learner$predict_newdata()
• mlr3::Learner$print()
• mlr3::Learner$reset()
• mlr3::Learner$selected_features()
• mlr3::Learner$train()

---

Method new()

Creates a new instance of this R6 class.

Usage

LearnerClassifSGD$new()

---

Method clone()

The objects of this class are cloneable with this method.

Usage

LearnerClassifSGD$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

# Define the Learner
learner = mlr3::lrn("classif.sgd")
print(learner)
#> 
#> ── <LearnerClassifSGD> (classif.sgd): Stochastic Gradient Descent ──────────────
#> • Model: -
#> • Parameters: F=0
#> • Packages: mlr3 and RWeka
#> • Predict Types: [response] and prob
#> • Feature Types: logical, integer, numeric, factor, and ordered
#> • Encapsulation: none (fallback: -)
#> • Properties: missings and twoclass
#> • Other settings: use_weights = 'error'

# Define a Task
task = mlr3::tsk("sonar")

# Create train and test set
ids = mlr3::partition(task)

# Train the learner on the training ids
learner$train(task, row_ids = ids$train)

print(learner$model)
#> Loss function: Hinge loss (SVM)
#> 
#> Class = 
#> 
#>         -0.7346 (normalized) V1
#>  +      -1.7841 (normalized) V10
#>  +      -1.1023 (normalized) V11
#>  +      -1.9158 (normalized) V12
#>  +      -1.9504 (normalized) V13
#>  +       0.5573 (normalized) V14
#>  +       0.5091 (normalized) V15
#>  +       3.0395 (normalized) V16
#>  +       1.6735 (normalized) V17
#>  +       0.4114 (normalized) V18
#>  +      -0.957  (normalized) V19
#>  +      -0.4664 (normalized) V2
#>  +      -0.6562 (normalized) V20
#>  +      -0.7603 (normalized) V21
#>  +      -1.2069 (normalized) V22
#>  +      -1.1724 (normalized) V23
#>  +      -0.7881 (normalized) V24
#>  +       1.2736 (normalized) V25
#>  +       1.1049 (normalized) V26
#>  +      -1.4597 (normalized) V27
#>  +       0.2752 (normalized) V28
#>  +      -0.2917 (normalized) V29
#>  +       0.3712 (normalized) V3
#>  +      -1.4876 (normalized) V30
#>  +       2.8814 (normalized) V31
#>  +      -0.8086 (normalized) V32
#>  +       0.9691 (normalized) V33
#>  +      -0.0772 (normalized) V34
#>  +      -0.6211 (normalized) V35
#>  +       1.8683 (normalized) V36
#>  +       0.4124 (normalized) V37
#>  +       0.0934 (normalized) V38
#>  +      -0.424  (normalized) V39
#>  +      -1.0038 (normalized) V4
#>  +       2.5093 (normalized) V40
#>  +      -0.2681 (normalized) V41
#>  +       0.0269 (normalized) V42
#>  +      -1.2142 (normalized) V43
#>  +      -1.9248 (normalized) V44
#>  +      -0.735  (normalized) V45
#>  +       0.0659 (normalized) V46
#>  +      -0.4827 (normalized) V47
#>  +      -0.285  (normalized) V48
#>  +      -2.9215 (normalized) V49
#>  +      -1.1722 (normalized) V5
#>  +       1.795  (normalized) V50
#>  +      -2.0655 (normalized) V51
#>  +      -1.2559 (normalized) V52
#>  +       0.3861 (normalized) V53
#>  +       0.2354 (normalized) V54
#>  +       3.4965 (normalized) V55
#>  +      -0.9008 (normalized) V56
#>  +       0.01   (normalized) V57
#>  +      -2.1571 (normalized) V58
#>  +      -0.4753 (normalized) V59
#>  +      -1.9947 (normalized) V6
#>  +      -0.1471 (normalized) V60
#>  +      -0.2373 (normalized) V7
#>  +       2.4032 (normalized) V8
#>  +      -2.8721 (normalized) V9
#>  +       3.96  


# Make predictions for the test rows
predictions = learner$predict(task, row_ids = ids$test)

# Score the predictions
predictions$score()
#> classif.ce 
#>  0.2608696