| ccp_alpha | Complexity parameter used for Minimal Cost-Complexity Pruning. The
subtree with the largest cost complexity that is smaller than
``ccp_alpha`` will be chosen. By default, no pruning is performed
Values must be in the range `[0.0, inf)`
See :ref:`minimal_cost_complexity_pruning` for details
.. versionadded:: 0.22 | default: 0.0 |
| criterion | | default: "friedman_mse" |
| init | An estimator object that is used to compute the initial predictions
``init`` has to provide :meth:`fit` and :meth:`predict_proba`. If
'zero', the initial raw predictions are set to zero. By default, a
``DummyEstimator`` predicting the classes priors is used | default: null |
| learning_rate | Learning rate shrinks the contribution of each tree by `learning_rate`
There is a trade-off between learning_rate and n_estimators
Values must be in the range `[0.0, inf)` | default: 0.1 |
| loss | | default: "log_loss" |
| max_depth | Maximum depth of the individual regression estimators. The maximum
depth limits the number of nodes in the tree. Tune this parameter
for best performance; the best value depends on the interaction
of the input variables. If None, then nodes are expanded until
all leaves are pure or until all leaves contain less than
min_samples_split samples
If int, values must be in the range `[1, inf)` | default: 3 |
| max_features | | default: null |
| max_leaf_nodes | Grow trees with ``max_leaf_nodes`` in best-first fashion
Best nodes are defined as relative reduction in impurity
Values must be in the range `[2, inf)`
If `None`, then unlimited number of leaf nodes | default: null |
| min_impurity_decrease | A node will be split if this split induces a decrease of the impurity
greater than or equal to this value
Values must be in the range `[0.0, inf)`
The weighted impurity decrease equation is the following::
N_t / N * (impurity - N_t_R / N_t * right_impurity
- N_t_L / N_t * left_impurity)
where ``N`` is the total number of samples, ``N_t`` is the number of
samples at the current node, ``N_t_L`` is the number of samples in the
left child, and ``N_t_R`` is the number of samples in the right child
``N``, ``N_t``, ``N_t_R`` and ``N_t_L`` all refer to the weighted sum,
if ``sample_weight`` is passed
.. versionadded:: 0.19 | default: 0.0 |
| min_samples_leaf | The minimum number of samples required to be at a leaf node
A split point at any depth will only be considered if it leaves at
least ``min_samples_leaf`` training samples in each of the left and
right branches. This may have the effect of smoothing the model,
especially in regression
- If int, values must be in the range `[1, inf)`
- If float, values must be in the range `(0.0, 1.0)` and `min_samples_leaf`
will be `ceil(min_samples_leaf * n_samples)`
.. versionchanged:: 0.18
Added float values for fractions | default: 1 |
| min_samples_split | The minimum number of samples required to split an internal node:
- If int, values must be in the range `[2, inf)`
- If float, values must be in the range `(0.0, 1.0]` and `min_samples_split`
will be `ceil(min_samples_split * n_samples)`
.. versionchanged:: 0.18
Added float values for fractions | default: 2 |
| min_weight_fraction_leaf | The minimum weighted fraction of the sum total of weights (of all
the input samples) required to be at a leaf node. Samples have
equal weight when sample_weight is not provided
Values must be in the range `[0.0, 0.5]` | default: 0.0 |
| n_estimators | The number of boosting stages to perform. Gradient boosting
is fairly robust to over-fitting so a large number usually
results in better performance
Values must be in the range `[1, inf)` | default: 100 |
| n_iter_no_change | ``n_iter_no_change`` is used to decide if early stopping will be used
to terminate training when validation score is not improving. By
default it is set to None to disable early stopping. If set to a
number, it will set aside ``validation_fraction`` size of the training
data as validation and terminate training when validation score is not
improving in all of the previous ``n_iter_no_change`` numbers of
iterations. The split is stratified
Values must be in the range `[1, inf)`
.. versionadded:: 0.20 | default: null |
| random_state | Controls the random seed given to each Tree estimator at each
boosting iteration
In addition, it controls the random permutation of the features at
each split (see Notes for more details)
It also controls the random splitting of the training data to obtain a
validation set if `n_iter_no_change` is not None
Pass an int for reproducible output across multiple function calls
See :term:`Glossary `
max_features : {'auto', 'sqrt', 'log2'}, int or float, default=None
The number of features to consider when looking for the best split:
- If int, values must be in the range `[1, inf)`
- If float, values must be in the range `(0.0, 1.0]` and the features
considered at each split will be `max(1, int(max_features * n_features_in_))`
- If 'auto', then `max_features=sqrt(n_features)`
- If 'sqrt', then `max_features=sqrt(n_features)`
- If 'log2', then `max_features=log2(n_features)`
- If None, then `max_features=n_features`
Choosing `max_fe... | default: null |
| subsample | The fraction of samples to be used for fitting the individual base
learners. If smaller than 1.0 this results in Stochastic Gradient
Boosting. `subsample` interacts with the parameter `n_estimators`
Choosing `subsample < 1.0` leads to a reduction of variance
and an increase in bias
Values must be in the range `(0.0, 1.0]`
criterion : {'friedman_mse', 'squared_error'}, default='friedman_mse'
The function to measure the quality of a split. Supported criteria are
'friedman_mse' for the mean squared error with improvement score by
Friedman, 'squared_error' for mean squared error. The default value of
'friedman_mse' is generally the best as it can provide a better
approximation in some cases
.. versionadded:: 0.18 | default: 1.0 |
| tol | Tolerance for the early stopping. When the loss is not improving
by at least tol for ``n_iter_no_change`` iterations (if set to a
number), the training stops
Values must be in the range `[0.0, inf)`
.. versionadded:: 0.20 | default: 0.0001 |
| validation_fraction | The proportion of training data to set aside as validation set for
early stopping. Values must be in the range `(0.0, 1.0)`
Only used if ``n_iter_no_change`` is set to an integer
.. versionadded:: 0.20 | default: 0.1 |
| verbose | Enable verbose output. If 1 then it prints progress and performance
once in a while (the more trees the lower the frequency). If greater
than 1 then it prints progress and performance for every tree
Values must be in the range `[0, inf)` | default: 0 |
| warm_start | When set to ``True``, reuse the solution of the previous call to fit
and add more estimators to the ensemble, otherwise, just erase the
previous solution. See :term:`the Glossary ` | default: false |