GreedyRegressor¶
Greedy selection regressor.
This selection method simply updates each model at each time step. The current best model is used to make predictions. It's greedy in the sense that updating each model can be costly. On the other hand, bandit-like algorithms are more temperate in that only update a subset of the models at each step.
Parameters¶
-
models (List[base.Regressor])
The models to select from.
-
metric (river.metrics.base.RegressionMetric) – defaults to
None
The metric that is used to measure the performance of each model.
Attributes¶
-
best_model
The current best model.
-
models
Examples¶
>>> from river import datasets
>>> from river import evaluate
>>> from river import linear_model
>>> from river import metrics
>>> from river import model_selection
>>> from river import optim
>>> from river import preprocessing
>>> models = [
... linear_model.LinearRegression(optimizer=optim.SGD(lr=lr))
... for lr in [1e-5, 1e-4, 1e-3, 1e-2]
... ]
>>> dataset = datasets.TrumpApproval()
>>> metric = metrics.MAE()
>>> model = (
... preprocessing.StandardScaler() |
... model_selection.GreedyRegressor(models, metric)
... )
>>> evaluate.progressive_val_score(dataset, model, metric)
MAE: 1.35
Methods¶
append
S.append(value) -- append value to the end of the sequence
Parameters
- item
clear
S.clear() -> None -- remove all items from S
clone
Return a fresh estimator with the same parameters.
The clone has the same parameters but has not been updated with any data. This works by looking at the parameters from the class signature. Each parameter is either - recursively cloned if it's a River classes. - deep-copied via copy.deepcopy
if not. If the calling object is stochastic (i.e. it accepts a seed parameter) and has not been seeded, then the clone will not be idempotent. Indeed, this method's purpose if simply to return a new instance with the same input parameters.
copy
count
S.count(value) -> integer -- return number of occurrences of value
Parameters
- item
extend
S.extend(iterable) -- extend sequence by appending elements from the iterable
Parameters
- other
index
S.index(value, [start, [stop]]) -> integer -- return first index of value. Raises ValueError if the value is not present.
Supporting start and stop arguments is optional, but recommended.
Parameters
- item
- args
insert
S.insert(index, value) -- insert value before index
Parameters
- i
- item
learn_one
Fits to a set of features x
and a real-valued target y
.
Parameters
- x (dict)
- y (numbers.Number)
Returns
Regressor: self
pop
S.pop([index]) -> item -- remove and return item at index (default last). Raise IndexError if list is empty or index is out of range.
Parameters
- i – defaults to
-1
predict_one
Predicts the target value of a set of features x
.
Parameters
- x
Returns
The prediction.
remove
S.remove(value) -- remove first occurrence of value. Raise ValueError if the value is not present.
Parameters
- item
reverse
S.reverse() -- reverse IN PLACE