Classification LightGBM Learner
mlr_learners_classif.lightgbm.Rd
Gradient boosting algorithm.
Calls lightgbm::lightgbm()
from lightgbm.
The list of parameters can be found here
and in the documentation of lightgbm::lgb.train()
.
Meta Information
Task type: “classif”
Predict Types: “response”, “prob”
Feature Types: “logical”, “integer”, “numeric”, “factor”
Required Packages: mlr3, mlr3extralearners, lightgbm
Parameters
Id | Type | Default | Levels | Range |
objective | character | - | binary, multiclass, multiclassova | - |
eval | untyped | - | - | |
verbose | integer | 1 | \((-\infty, \infty)\) | |
record | logical | TRUE | TRUE, FALSE | - |
eval_freq | integer | 1 | \([1, \infty)\) | |
callbacks | untyped | - | - | |
reset_data | logical | FALSE | TRUE, FALSE | - |
boosting | character | gbdt | gbdt, rf, dart, goss | - |
linear_tree | logical | FALSE | TRUE, FALSE | - |
learning_rate | numeric | 0.1 | \([0, \infty)\) | |
num_leaves | integer | 31 | \([1, 131072]\) | |
tree_learner | character | serial | serial, feature, data, voting | - |
num_threads | integer | 0 | \([0, \infty)\) | |
device_type | character | cpu | cpu, gpu | - |
seed | integer | - | \((-\infty, \infty)\) | |
deterministic | logical | FALSE | TRUE, FALSE | - |
data_sample_strategy | character | bagging | bagging, goss | - |
force_col_wise | logical | FALSE | TRUE, FALSE | - |
force_row_wise | logical | FALSE | TRUE, FALSE | - |
histogram_pool_size | numeric | -1 | \((-\infty, \infty)\) | |
max_depth | integer | -1 | \((-\infty, \infty)\) | |
min_data_in_leaf | integer | 20 | \([0, \infty)\) | |
min_sum_hessian_in_leaf | numeric | 0.001 | \([0, \infty)\) | |
bagging_fraction | numeric | 1 | \([0, 1]\) | |
pos_bagging_fraction | numeric | 1 | \([0, 1]\) | |
neg_bagging_fraction | numeric | 1 | \([0, 1]\) | |
bagging_freq | integer | 0 | \([0, \infty)\) | |
bagging_seed | integer | 3 | \((-\infty, \infty)\) | |
bagging_by_query | logical | FALSE | TRUE, FALSE | - |
feature_fraction | numeric | 1 | \([0, 1]\) | |
feature_fraction_bynode | numeric | 1 | \([0, 1]\) | |
feature_fraction_seed | integer | 2 | \((-\infty, \infty)\) | |
extra_trees | logical | FALSE | TRUE, FALSE | - |
extra_seed | integer | 6 | \((-\infty, \infty)\) | |
max_delta_step | numeric | 0 | \((-\infty, \infty)\) | |
lambda_l1 | numeric | 0 | \([0, \infty)\) | |
lambda_l2 | numeric | 0 | \([0, \infty)\) | |
linear_lambda | numeric | 0 | \([0, \infty)\) | |
min_gain_to_split | numeric | 0 | \([0, \infty)\) | |
drop_rate | numeric | 0.1 | \([0, 1]\) | |
max_drop | integer | 50 | \((-\infty, \infty)\) | |
skip_drop | numeric | 0.5 | \([0, 1]\) | |
xgboost_dart_mode | logical | FALSE | TRUE, FALSE | - |
uniform_drop | logical | FALSE | TRUE, FALSE | - |
drop_seed | integer | 4 | \((-\infty, \infty)\) | |
top_rate | numeric | 0.2 | \([0, 1]\) | |
other_rate | numeric | 0.1 | \([0, 1]\) | |
min_data_per_group | integer | 100 | \([1, \infty)\) | |
max_cat_threshold | integer | 32 | \([1, \infty)\) | |
cat_l2 | numeric | 10 | \([0, \infty)\) | |
cat_smooth | numeric | 10 | \([0, \infty)\) | |
max_cat_to_onehot | integer | 4 | \([1, \infty)\) | |
top_k | integer | 20 | \([1, \infty)\) | |
monotone_constraints | untyped | NULL | - | |
monotone_constraints_method | character | basic | basic, intermediate, advanced | - |
monotone_penalty | numeric | 0 | \([0, \infty)\) | |
feature_contri | untyped | NULL | - | |
forcedsplits_filename | untyped | "" | - | |
refit_decay_rate | numeric | 0.9 | \([0, 1]\) | |
cegb_tradeoff | numeric | 1 | \([0, \infty)\) | |
cegb_penalty_split | numeric | 0 | \([0, \infty)\) | |
cegb_penalty_feature_lazy | untyped | - | - | |
cegb_penalty_feature_coupled | untyped | - | - | |
path_smooth | numeric | 0 | \([0, \infty)\) | |
interaction_constraints | untyped | - | - | |
use_quantized_grad | logical | TRUE | TRUE, FALSE | - |
num_grad_quant_bins | integer | 4 | \((-\infty, \infty)\) | |
quant_train_renew_leaf | logical | FALSE | TRUE, FALSE | - |
stochastic_rounding | logical | TRUE | TRUE, FALSE | - |
serializable | logical | TRUE | TRUE, FALSE | - |
max_bin | integer | 255 | \([2, \infty)\) | |
max_bin_by_feature | untyped | NULL | - | |
min_data_in_bin | integer | 3 | \([1, \infty)\) | |
bin_construct_sample_cnt | integer | 200000 | \([1, \infty)\) | |
data_random_seed | integer | 1 | \((-\infty, \infty)\) | |
is_enable_sparse | logical | TRUE | TRUE, FALSE | - |
enable_bundle | logical | TRUE | TRUE, FALSE | - |
use_missing | logical | TRUE | TRUE, FALSE | - |
zero_as_missing | logical | FALSE | TRUE, FALSE | - |
feature_pre_filter | logical | TRUE | TRUE, FALSE | - |
pre_partition | logical | FALSE | TRUE, FALSE | - |
two_round | logical | FALSE | TRUE, FALSE | - |
forcedbins_filename | untyped | "" | - | |
is_unbalance | logical | FALSE | TRUE, FALSE | - |
scale_pos_weight | numeric | 1 | \([0, \infty)\) | |
sigmoid | numeric | 1 | \([0, \infty)\) | |
boost_from_average | logical | TRUE | TRUE, FALSE | - |
eval_at | untyped | 1:5 | - | |
multi_error_top_k | integer | 1 | \([1, \infty)\) | |
auc_mu_weights | untyped | NULL | - | |
num_machines | integer | 1 | \([1, \infty)\) | |
local_listen_port | integer | 12400 | \([1, \infty)\) | |
time_out | integer | 120 | \([1, \infty)\) | |
machines | untyped | "" | - | |
gpu_platform_id | integer | -1 | \((-\infty, \infty)\) | |
gpu_device_id | integer | -1 | \((-\infty, \infty)\) | |
gpu_use_dp | logical | FALSE | TRUE, FALSE | - |
num_gpu | integer | 1 | \([1, \infty)\) | |
start_iteration_predict | integer | 0 | \((-\infty, \infty)\) | |
num_iteration_predict | integer | -1 | \((-\infty, \infty)\) | |
pred_early_stop | logical | FALSE | TRUE, FALSE | - |
pred_early_stop_freq | integer | 10 | \((-\infty, \infty)\) | |
pred_early_stop_margin | numeric | 10 | \((-\infty, \infty)\) | |
num_iterations | integer | 100 | \([1, \infty)\) | |
early_stopping_rounds | integer | - | \([1, \infty)\) | |
early_stopping_min_delta | numeric | - | \([0, \infty)\) | |
first_metric_only | logical | FALSE | TRUE, FALSE | - |
Initial parameter values
num_threads
:Actual default: 0L
Initial value: 1L
Reason for change: Prevents accidental conflicts with
future
.
verbose
:Actual default: 1L
Initial value: -1L
Reason for change: Prevents accidental conflicts with mlr messaging system.
objective
:Depends on the task: if binary classification, then this parameter is set to
"binary"
, otherwise"multiclasss"
and cannot be changed.
Custom mlr3 parameters
num_class
: This parameter is automatically inferred for multiclass tasks and does not have to be set.
Early Stopping and Validation
Early stopping can be used to find the optimal number of boosting rounds.
Set early_stopping_rounds
to an integer value to monitor the performance of the model on the validation set while training.
For information on how to configure the validation set, see the Validation section of mlr3::Learner
.
The internal validation measure can be set the eval
parameter which should be a list of mlr3::Measures, functions, or strings for the internal lightgbm measures.
If first_metric_only = FALSE
(default), the learner stops when any metric fails to improve.
References
Ke, Guolin, Meng, Qi, Finley, Thomas, Wang, Taifeng, Chen, Wei, Ma, Weidong, Ye, Qiwei, Liu, Tie-Yan (2017). “Lightgbm: A highly efficient gradient boosting decision tree.” Advances in neural information processing systems, 30.
See also
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.
Super classes
mlr3::Learner
-> mlr3::LearnerClassif
-> LearnerClassifLightGBM
Active bindings
internal_valid_scores
The last observation of the validation scores for all metrics. Extracted from
model$evaluation_log
internal_tuned_values
Returns the early stopped iterations if
early_stopping_rounds
was set during training.validate
How to construct the internal validation data. This parameter can be either
NULL
, a ratio,"test"
, or"predefined"
.
Methods
Method importance()
The importance scores are extracted from lbg.importance
.
Returns
Named numeric()
.
Examples
# Define the Learner
learner = mlr3::lrn("classif.lightgbm")
print(learner)
#> <LearnerClassifLightGBM:classif.lightgbm>: Gradient Boosting
#> * Model: -
#> * Parameters: verbose=-1, num_threads=1
#> * Validate: NULL
#> * Packages: mlr3, mlr3extralearners, lightgbm
#> * Predict Types: response, [prob]
#> * Feature Types: logical, integer, numeric, factor
#> * Properties: hotstart_forward, importance, internal_tuning, missings,
#> multiclass, twoclass, validation, weights
# Define a Task
task = mlr3::tsk("sonar")
# Create train and test set
ids = mlr3::partition(task)
# Train the learner on the training ids
learner$train(task, row_ids = ids$train)
print(learner$model)
#> LightGBM Model (100 trees)
#> Objective: binary
#> Fitted to dataset with 60 columns
print(learner$importance())
#> V11 V36 V51 V12 V45 V4
#> 0.2094792806 0.1039171170 0.0939527368 0.0635646086 0.0482588751 0.0456900826
#> V23 V17 V18 V46 V16 V55
#> 0.0341961434 0.0305822350 0.0273184109 0.0257967325 0.0252455018 0.0232948186
#> V5 V59 V20 V49 V37 V28
#> 0.0227087375 0.0223644471 0.0193781201 0.0181761910 0.0155918375 0.0141580489
#> V10 V9 V43 V33 V47 V60
#> 0.0128763304 0.0125905366 0.0097843748 0.0097255438 0.0087606033 0.0080004614
#> V21 V39 V2 V32 V58 V41
#> 0.0078067095 0.0073460969 0.0069962695 0.0066758555 0.0061262795 0.0056241773
#> V31 V30 V54 V27 V19 V25
#> 0.0055334319 0.0053987973 0.0052795049 0.0047560731 0.0034044087 0.0031985364
#> V29 V1 V22 V52 V7 V3
#> 0.0031222462 0.0026210823 0.0021331888 0.0020904096 0.0020389133 0.0017223558
#> V8 V40 V53 V56 V34 V24
#> 0.0013628860 0.0012223363 0.0011870496 0.0011476060 0.0010464975 0.0010089051
#> V26 V48 V38 V42 V14 V15
#> 0.0009166073 0.0008928191 0.0008544917 0.0008314035 0.0006684843 0.0004632970
#> V35 V13 V44
#> 0.0004533684 0.0004281820 0.0002299546
# Make predictions for the test rows
predictions = learner$predict(task, row_ids = ids$test)
# Score the predictions
predictions$score()
#> classif.ce
#> 0.1594203