SoftmaxRegression¶
Softmax regression is a generalization of logistic regression to multiple classes.
Softmax regression is also known as "multinomial logistic regression". There are a set weights for each class, hence the weights attribute is a nested collections.defaultdict. The main advantage of using this instead of a one-vs-all logistic regression is that the probabilities will be calibrated. Moreover softmax regression is more robust to outliers.
Parameters¶
-
optimizer (optim.Optimizer) – defaults to
NoneThe sequential optimizer used to tune the weights.
-
loss (optim.losses.MultiClassLoss) – defaults to
NoneThe loss function to optimize for.
-
l2 – defaults to
0Amount of L2 regularization used to push weights towards 0.
Attributes¶
- weights (collections.defaultdict)
Examples¶
>>> from river import datasets
>>> from river import evaluate
>>> from river import linear_model
>>> from river import metrics
>>> from river import optim
>>> from river import preprocessing
>>> dataset = datasets.ImageSegments()
>>> model = preprocessing.StandardScaler()
>>> model |= linear_model.SoftmaxRegression()
>>> metric = metrics.MacroF1()
>>> evaluate.progressive_val_score(dataset, model, metric)
MacroF1: 0.818765
Methods¶
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.
learn_one
Update the model with a set of features x and a label y.
Parameters
- x (dict)
- y (Union[bool, str, int])
Returns
Classifier: self
predict_many
Predict the labels of a DataFrame X.
Parameters
- X (pandas.core.frame.DataFrame)
Returns
Series: Series of predicted labels.
predict_one
Predict the label of a set of features x.
Parameters
- x (dict)
Returns
typing.Union[bool, str, int]: The predicted label.
predict_proba_many
Predict the labels of a DataFrame X.
Parameters
- X (pandas.core.frame.DataFrame)
Returns
DataFrame: DataFrame that associate probabilities which each label as columns.
predict_proba_one
Predict the probability of each label for a dictionary of features x.
Parameters
- x (dict)
Returns
typing.Dict[typing.Union[bool, str, int], float]: A dictionary that associates a probability which each label.