skmultiflow.data.HyperplaneGenerator

class skmultiflow.data.HyperplaneGenerator(random_state=None, n_features=10, n_drift_features=2, mag_change=0.0, noise_percentage=0.05, sigma_percentage=0.1)[source]

Hyperplane stream generator.

Generates a problem of prediction class of a rotation hyperplane. It was used as testbed for CVFDT and VFDT in [1].

A hyperplane in d-dimensional space is the set of points \(x\) that satisfy \(\sum^{d}_{i=1} w_i x_i = w_0 = \sum^{d}_{i=1} w_i\), where \(x_i\) is the ith coordinate of \(x\). Examples for which \(\sum^{d}_{i=1} w_i x_i > w_0\), are labeled positive, and examples for which \(\sum^{d}_{i=1} w_i x_i \leq w_0\), are labeled negative.

Hyperplanes are useful for simulating time-changing concepts, because we can change the orientation and position of the hyperplane in a smooth manner by changing the relative size of the weights. We introduce change to this dataset by adding drift to each weight feature \(w_i = w_i + d \sigma\), where \(\sigma\) is the probability that the direction of change is reversed and \(d\) is the change applied to every example.

Parameters
random_state: int, RandomState instance or None, optional (default=None)

If int, random_state is the seed used by the random number generator; If RandomState instance, random_state is the random number generator; If None, the random number generator is the RandomState instance used by np.random.

n_features: int (Default 10)

The number of attributes to generate. Higher than 2.

n_drift_features: int (Default: 2)

The number of attributes with drift. Higher than 2.

mag_change: float (Default: 0.0)

Magnitude of the change for every example. From 0.0 to 1.0.

noise_percentage: float (Default: 0.05)

Percentage of noise to add to the data. From 0.0 to 1.0.

sigma_percentage: int (Default 0.1)

Percentage of probability that the direction of change is reversed. From 0.0 to 1.0.

References

1

G. Hulten, L. Spencer, and P. Domingos. Mining time-changing data streams. In KDD’01, pages 97–106, San Francisco, CA, 2001. ACM Press.

Methods

get_data_info(self)

Retrieves minimum information from the stream

get_info(self)

Collects and returns the information about the configuration of the estimator

get_params(self[, deep])

Get parameters for this estimator.

has_more_samples(self)

Checks if stream has more samples.

is_restartable(self)

Determine if the stream is restartable.

last_sample(self)

Retrieves last batch_size samples in the stream.

n_remaining_samples(self)

Returns the estimated number of remaining samples.

next_sample(self[, batch_size])

Returns next sample from the stream.

prepare_for_use()

Prepare the stream for use.

reset(self)

Resets the estimator to its initial state.

restart(self)

Restart the stream.

set_params(self, **params)

Set the parameters of this estimator.

Attributes

feature_names

Retrieve the names of the features.

mag_change

Retrieve the value of the value of magnitude of change.

n_cat_features

Retrieve the number of integer features.

n_drift_features

Retrieve the number of drift features.

n_features

Retrieve the number of features.

n_num_features

Retrieve the number of numerical features.

n_targets

Retrieve the number of targets

noise_percentage

Retrieve the value of the value of Noise percentage

sigma_percentage

Retrieve the value of the value of sigma percentage

target_names

Retrieve the names of the targets

target_values

Retrieve all target_values in the stream for each target.

property feature_names

Retrieve the names of the features.

Returns
list

names of the features

get_data_info(self)[source]

Retrieves minimum information from the stream

Used by evaluator methods to id the stream.

The default format is: ‘Stream name - n_targets, n_classes, n_features’.

Returns
string

Stream data information

get_info(self)[source]

Collects and returns the information about the configuration of the estimator

Returns
string

Configuration of the estimator.

get_params(self, deep=True)[source]

Get parameters for this estimator.

Parameters
deepboolean, optional

If True, will return the parameters for this estimator and contained subobjects that are estimators.

Returns
paramsmapping of string to any

Parameter names mapped to their values.

has_more_samples(self)[source]

Checks if stream has more samples.

Returns
Boolean

True if stream has more samples.

is_restartable(self)[source]

Determine if the stream is restartable.

Returns
Bool

True if stream is restartable.

last_sample(self)[source]

Retrieves last batch_size samples in the stream.

Returns
tuple or tuple list

A numpy.ndarray of shape (batch_size, n_features) and an array-like of shape (batch_size, n_targets), representing the next batch_size samples.

property mag_change

Retrieve the value of the value of magnitude of change.

Returns
float

magnitude of change

property n_cat_features

Retrieve the number of integer features.

Returns
int

The number of integer features in the stream.

property n_drift_features

Retrieve the number of drift features.

Returns
int

The total number of drift features.

property n_features

Retrieve the number of features.

Returns
int

The total number of features.

property n_num_features

Retrieve the number of numerical features.

Returns
int

The number of numerical features in the stream.

n_remaining_samples(self)[source]

Returns the estimated number of remaining samples.

Returns
int

Remaining number of samples. -1 if infinite (e.g. generator)

property n_targets

Retrieve the number of targets

Returns
int

the number of targets in the stream.

next_sample(self, batch_size=1)[source]

Returns next sample from the stream.

The sample generation works as follows: The features are generated with the random generator, initialized with the seed passed by the user. Then the classification function decides, as a function of the sum and weight’s sum, whether to instance belongs to class 0 or class 1. The next step is to add noise if requested by the user and than generate drift.

Parameters
batch_size: int (optional, default=1)

The number of samples to return.

Returns
tuple or tuple list

Return a tuple with the features matrix and the labels matrix for the batch_size samples that were requested.

property noise_percentage

Retrieve the value of the value of Noise percentage

Returns
float

percentage of the noise

static prepare_for_use()[source]

Prepare the stream for use.

Deprecated in v0.5.0 and will be removed in v0.7.0

reset(self)[source]

Resets the estimator to its initial state.

Returns
self
restart(self)[source]

Restart the stream.

set_params(self, **params)[source]

Set the parameters of this estimator.

The method works on simple estimators as well as on nested objects (such as pipelines). The latter have parameters of the form <component>__<parameter> so that it’s possible to update each component of a nested object.

Returns
self
property sigma_percentage

Retrieve the value of the value of sigma percentage

Returns
float

percentage of the sigma

property target_names

Retrieve the names of the targets

Returns
list

the names of the targets in the stream.

property target_values

Retrieve all target_values in the stream for each target.

Returns
list

list of lists of all target_values for each target