# copulas.univariate.base module¶

class copulas.univariate.base.BoundedType[source]

Bases: enum.Enum

An enumeration.

BOUNDED = 2
SEMI_BOUNDED = 1
UNBOUNDED = 0
class copulas.univariate.base.ParametricType[source]

Bases: enum.Enum

An enumeration.

NON_PARAMETRIC = 0
PARAMETRIC = 1
class copulas.univariate.base.ScipyModel(*args, **kwargs)[source]

Bases: copulas.univariate.base.Univariate, abc.ABC

Wrapper for scipy models.

This class makes the probability_density, cumulative_distribution, percent_point and sample point at the underlying pdf, cdf, ppd and rvs methods respectively.

fit, _get_params and _set_params must be implemented by the subclasses.

MODEL_CLASS = None
cumulative_distribution(X)[source]

Compute the cumulative distribution value for each point in X.

Parameters

X (numpy.ndarray) – Values for which the cumulative distribution will be computed. It must have shape (n, 1).

Returns

Cumulative distribution values for points in X.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

fit(X)[source]

Fit the model to a random variable.

Parameters

X (numpy.ndarray) – Values of the random variable. It must have shape (n, 1).

log_probability_density(X)[source]

Compute the log of the probability density for each point in X.

Parameters

X (numpy.ndarray) – Values for which the log probability density will be computed. It must have shape (n, 1).

Returns

Log probability density values for points in X.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

percent_point(U)[source]

Compute the inverse cumulative distribution value for each point in U.

Parameters

U (numpy.ndarray) – Values for which the cumulative distribution will be computed. It must have shape (n, 1) and values must be in [0,1].

Returns

Inverse cumulative distribution values for points in U.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

probability_density(X)[source]

Compute the probability density for each point in X.

Parameters

X (numpy.ndarray) – Values for which the probability density will be computed. It must have shape (n, 1).

Returns

Probability density values for points in X.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

sample(n_samples=1)[source]

Sample values from this model.

Argument:
n_samples (int):

Number of values to sample

Returns

Array of shape (n_samples, 1) with values randomly sampled from this model distribution.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

class copulas.univariate.base.Univariate(*args, **kwargs)[source]

Bases: object

Univariate Distribution.

Parameters
• candidates (list[str or type or Univariate]) – List of candidates to select the best univariate from. It can be a list of strings representing Univariate FQNs, or a list of Univariate subclasses or a list of instances.

• parametric (ParametricType) – If not None, only select subclasses of this type. Ignored if candidates is passed.

• bounded (BoundedType) – If not None, only select subclasses of this type. Ignored if candidates is passed.

• random_seed (int) – Random seed to use.

• selection_sample_size (int) – Size of the subsample to use for candidate selection. If None, all the data is used.

BOUNDED = 0
PARAMETRIC = 0
cdf(X)[source]

Compute the cumulative distribution value for each point in X.

Parameters

X (numpy.ndarray) – Values for which the cumulative distribution will be computed. It must have shape (n, 1).

Returns

Cumulative distribution values for points in X.

Return type

numpy.ndarray

check_fit()[source]

Check whether this model has already been fit to a random variable.

Raise a NotFittedError if it has not.

Raises

NotFittedError – if the model is not fitted.

cumulative_distribution(X)[source]

Compute the cumulative distribution value for each point in X.

Parameters

X (numpy.ndarray) – Values for which the cumulative distribution will be computed. It must have shape (n, 1).

Returns

Cumulative distribution values for points in X.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

fit(X)[source]

Fit the model to a random variable.

Parameters

X (numpy.ndarray) – Values of the random variable. It must have shape (n, 1).

fitted = False
classmethod from_dict(params)[source]

Build a distribution from its params dict.

Parameters

params (dict) – Dictionary containing the FQN of the distribution and the necessary parameters to rebuild it. The input format is exactly the same that is outputted by the distribution class to_dict method.

Returns

Distribution instance.

Return type

Univariate

classmethod load(path)[source]

Load a Univariate instance from a pickle file.

Parameters

path (str) – Path to the pickle file where the distribution has been serialized.

Returns

Return type

Univariate

log_probability_density(X)[source]

Compute the log of the probability density for each point in X.

It should be overridden with numerically stable variants whenever possible.

Parameters

X (numpy.ndarray) – Values for which the log probability density will be computed. It must have shape (n, 1).

Returns

Log probability density values for points in X.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

pdf(X)[source]

Compute the probability density for each point in X.

Parameters

X (numpy.ndarray) – Values for which the probability density will be computed. It must have shape (n, 1).

Returns

Probability density values for points in X.

Return type

numpy.ndarray

percent_point(U)[source]

Compute the inverse cumulative distribution value for each point in U.

Parameters

U (numpy.ndarray) – Values for which the cumulative distribution will be computed. It must have shape (n, 1) and values must be in [0,1].

Returns

Inverse cumulative distribution values for points in U.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

ppf(U)[source]

Compute the inverse cumulative distribution value for each point in U.

Parameters

U (numpy.ndarray) – Values for which the cumulative distribution will be computed. It must have shape (n, 1) and values must be in [0,1].

Returns

Inverse cumulative distribution values for points in U.

Return type

numpy.ndarray

probability_density(X)[source]

Compute the probability density for each point in X.

Parameters

X (numpy.ndarray) – Values for which the probability density will be computed. It must have shape (n, 1).

Returns

Probability density values for points in X.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

sample(n_samples=1)[source]

Sample values from this model.

Argument:
n_samples (int):

Number of values to sample

Returns

Array of shape (n_samples, 1) with values randomly sampled from this model distribution.

Return type

numpy.ndarray

Raises

NotFittedError – if the model is not fitted.

save(path)[source]

Serialize this univariate instance using pickle.

Parameters

path (str) – Path to where this distribution will be serialized.

to_dict()[source]

Return the parameters of this model in a dict.

Returns

Dictionary containing the distribution type and all the parameters that define the distribution.

Return type

dict

Raises

NotFittedError – if the model is not fitted.