def __init__(self, data_navigator, model=DEFAULT_MODEL, distribution=None, model_kwargs=None):
"""Instantiates a modeler object.
"""
self.tables = {}
self.models = {}
self.child_locs = {} # maps table->{child: col #}
self.dn = data_navigator
self.model = model
if distribution and model != DEFAULT_MODEL:
raise ValueError(
'`distribution` argument is only suported for `GaussianMultivariate` model.')
if distribution:
distribution = get_qualified_name(distribution)
else:
distribution = get_qualified_name(DEFAULT_DISTRIBUTION)
if not model_kwargs:
if model == DEFAULT_MODEL:
model_kwargs = {'distribution': distribution}
else:
model_kwargs = {'vine_type': TreeTypes.REGULAR}
self.model_kwargs = model_kwargs
def _make_model_from_params(self, parent_row, table_name, parent_name):
""" Takes the params from a generated parent row and creates a model from it.
Args:
parent_row (dataframe): a generated parent row
table_name (string): name of table to make model for
parent_name (string): name of parent table
"""
# get parameters
child_range = self.modeler.child_locs.get(parent_name, {}).get(table_name, {})
if not child_range:
return None
param_indices = list(range(child_range[0], child_range[1]))
params = parent_row.loc[:, param_indices]
totalcols = params.shape[1]
num_cols = self.modeler.tables[table_name].shape[1]
# get labels for dataframe
labels = list(self.modeler.tables[table_name].columns)
# parent_meta = self.dn.tables[parent_name].meta
# fk = parent_meta['primary_key']
# if fk in labels:
# labels.remove(fk)
# num_cols -= 1
cov_size = num_cols ** 2
# Covariance matrix
covariance = params.iloc[:, 0:cov_size]
covariance = covariance.values.reshape((num_cols, num_cols))
# Distributions
distributions = {}
for label_index, i in enumerate(range(cov_size, totalcols, 2)):
distributions[labels[label_index]] = {
'type': get_qualified_name(self.modeler.distribution),
'fitted': True,
'std': abs(params.iloc[:, i]), # Pending for issue
'mean': params.iloc[:, i + 1], # https://github.com/HDI-Project/SDV/issues/58
}
model_params = {
'covariance': covariance,
'distribs': distributions,
'type': get_qualified_name(self.modeler.model),
'fitted': True,
'distribution': get_qualified_name(self.modeler.distribution)
}
return self.modeler.model.from_dict(model_params)
def unflatten_model(self, parent_row, table_name, parent_name):
""" Takes the params from a generated parent row and creates a model from it.
Args:
parent_row (dataframe): a generated parent row
table_name (string): name of table to make model for
parent_name (string): name of parent table
"""
prefix = '__{}__'.format(table_name)
columns = [
column for column in parent_row.columns
if column.startswith(prefix)
]
new_columns = {
column: column.replace(prefix, '')
for column in columns
}
flat_parameters = parent_row.loc[:, columns]
flat_parameters = flat_parameters.rename(
columns=new_columns).to_dict('records')[0]
model_parameters = self._unflatten_dict(flat_parameters, table_name)
model_name = get_qualified_name(self.modeler.model)
model_parameters['fitted'] = True
model_parameters['type'] = model_name
if model_name == GAUSSIAN_COPULA:
model_parameters = self._unflatten_gaussian_copula(
model_parameters)
return self.modeler.model.from_dict(model_parameters)
def flatten_model(self, model, name=''):
"""Flatten a model's parameters into an array.
Args:
model(self.model): Instance of model.
name (str): Prefix to the parameter name.
Returns:
pd.Series: parameters for model
"""
if self.model == DEFAULT_MODEL:
values = []
triangle = np.tril(model.covariance)
for index, row in enumerate(triangle.tolist()):
values.append(row[:index + 1])
model.covariance = np.array(values)
if self.model_kwargs['distribution'] == get_qualified_name(DEFAULT_DISTRIBUTION):
transformer = PositiveNumberTransformer({
'name': 'field',
'type': 'number'
})
for distribution in model.distribs.values():
column = pd.DataFrame({'field': [distribution.std]})
distribution.std = transformer.reverse_transform(column).loc[0, 'field']
return pd.Series(self._flatten_dict(model.to_dict(), name))
def to_dict(self):
result = {
'type': get_qualified_name(self),
'vine_type': self.vine_type,
'fitted': self.fitted
}
if not self.fitted:
return result
result.update({
'n_sample':
self.n_sample,
'n_var':
self.n_var,
'depth':
self.depth,
'truncated':
self.truncated,
'trees': [tree.to_dict() for tree in self.trees],
'tau_mat':
self.tau_mat.tolist(),
'u_matrix':
self.u_matrix.tolist(),
'unis': [distribution.to_dict() for distribution in self.unis],
})
return result
def to_dict(self):
"""Return a `dict` with the parameters to replicate this Vine.
Returns:
dict:
Parameters of this Vine.
"""
result = {
'type': get_qualified_name(self),
'vine_type': self.vine_type,
'fitted': self.fitted
}
if not self.fitted:
return result
result.update({
'n_sample':
self.n_sample,
'n_var':
self.n_var,
'depth':
self.depth,
'truncated':
self.truncated,
'trees': [tree.to_dict() for tree in self.trees],
'tau_mat':
self.tau_mat.tolist(),
'u_matrix':
self.u_matrix.tolist(),
'unis': [distribution.to_dict() for distribution in self.unis],
'columns':
self.columns
})
return result
def to_dict(self):
"""Returns parameters to replicate the distribution."""
result = {'type': get_qualified_name(self), 'fitted': self.fitted}
if not self.fitted:
return result
if get_qualified_name(self) == get_qualified_name(Univariate):
if self.constant_value is not None:
result["constant_value"] = self.constant_value
return result
else:
result['instance_type'] = get_qualified_name(self._instance)
result.update(self._fit_params())
return result
def _get_model_dict(self, data):
"""Fit and serialize a model and flatten its parameters into an array.
Args:
data(pandas.DataFrame): Dataset to fit the model to.
Returns:
dict: Flattened parameters for model.
"""
model = self.fit_model(data)
if self.model == DEFAULT_MODEL:
values = []
triangle = np.tril(model.covariance)
for index, row in enumerate(triangle.tolist()):
values.append(row[:index + 1])
model.covariance = np.array(values)
if self.model_kwargs['distribution'] == get_qualified_name(
DEFAULT_DISTRIBUTION):
transformer = PositiveNumberTransformer({
'name': 'field',
'type': 'number'
})
for distribution in model.distribs.values():
column = pd.DataFrame({'field': [distribution.std]})
distribution.std = transformer.reverse_transform(
column).loc[0, 'field']
return self._flatten_dict(model.to_dict())
def to_dict(self):
"""Return a `dict` with the parameters to replicate this Tree.
Returns:
dict:
Parameters of this Tree.
"""
fitted = self.fitted
result = {
'tree_type': self.tree_type,
'type': get_qualified_name(self),
'fitted': fitted
}
if not fitted:
return result
result.update({
'level': self.level,
'n_nodes': self.n_nodes,
'tau_matrix': self.tau_matrix.tolist(),
'previous_tree': self._serialize_previous_tree(),
'edges': [edge.to_dict() for edge in self.edges],
})
return result
def test_fit_distribution_selector(self):
"""
On fit, it should use the correct distributions for those that are
specified and default to using the base class otherwise.
"""
copula = GaussianMultivariate(distribution={
'column1': 'copulas.univariate.beta.BetaUnivariate',
'column2': 'copulas.univariate.gaussian_kde.GaussianKDE',
})
copula.fit(self.data)
assert get_qualified_name(
copula.univariates[0].__class__) == 'copulas.univariate.beta.BetaUnivariate'
assert get_qualified_name(
copula.univariates[1].__class__) == 'copulas.univariate.gaussian_kde.GaussianKDE'
assert get_qualified_name(
copula.univariates[2].__class__) == 'copulas.univariate.base.Univariate'
def from_dict(cls, param_dict):
"""Create new instance from dictionary."""
distribution_class = get_instance(param_dict['type'])
if get_qualified_name(distribution_class) == get_qualified_name(
Univariate):
distribution_class.fitted = param_dict['fitted']
if distribution_class.fitted:
if param_dict.get("constant_value", None) is not None:
distribution_class.constant_value = param_dict[
"constant_value"]
distribution_class._replace_constant_methods()
else:
instance_class = get_instance(param_dict['instance_type'])
distribution_class._instance = instance_class.from_dict(
param_dict)
return distribution_class
return distribution_class.from_dict(param_dict)
def to_dict(self):
"""Returns parameters to replicate the distribution."""
result = {'type': get_qualified_name(self), 'fitted': self.fitted}
if not self.fitted:
return result
result.update(self._fit_params())
return result
def to_dict(self):
"""Return the parameters of this model in a dict.
Returns:
dict:
Dictionary containing the distribution type and all
the parameters that define the distribution.
Raises:
NotFittedError:
if the model is not fitted.
"""
self.check_fit()
params = self._get_params()
if self.__class__ is Univariate:
params['type'] = get_qualified_name(self._instance)
else:
params['type'] = get_qualified_name(self)
return params
def _get_model(self, extension):
"""Build a model using the extension parameters."""
model_parameters = self._unflatten_dict(extension)
model_name = get_qualified_name(self.modeler.model)
model_parameters['fitted'] = True
model_parameters['type'] = model_name
if model_name == GAUSSIAN_COPULA:
model_parameters = self._unflatten_gaussian_copula(model_parameters)
return self.modeler.model.from_dict(model_parameters)
def to_dict(self):
distributions = {
name: distribution.to_dict() for name, distribution in self.distribs.items()
}
return {
'covariance': self.covariance.tolist(),
'distribs': distributions,
'type': get_qualified_name(self),
'fitted': self.fitted,
'distribution': self.distribution
}
def to_dict(self):
univariates = [univariate.to_dict() for univariate in self.univariates]
distribution = self.distribution
if isinstance(self.distribution, dict):
distribution = {}
for k, v in self.distribution.items():
distribution[k] = v.to_dict()
return {
'covariance': self.covariance.tolist(),
'univariates': univariates,
'columns': self.columns,
'type': get_qualified_name(self),
'fitted': self.fitted,
'distribution': distribution
}
def to_dict(self):
"""Return a `dict` with the parameters to replicate this object.
Returns:
dict:
Parameters of this distribution.
"""
self.check_fit()
univariates = [univariate.to_dict() for univariate in self.univariates]
return {
'covariance': self.covariance.tolist(),
'univariates': univariates,
'columns': self.columns,
'type': get_qualified_name(self),
}
def to_dict(self):
"""Return a `dict` with the parameters to replicate this object.
Returns:
dict:
Parameters of this distribution.
"""
self.check_fit()
univariates = [univariate.to_dict() for univariate in self.univariates]
warnings.warn('`covariance` will be renamed to `correlation` in v0.4.0',
DeprecationWarning)
return {
'covariance': self.covariance.tolist(),
'univariates': univariates,
'columns': self.columns,
'type': get_qualified_name(self),
}
def test_fit_distribution_arg(self):
"""On fit, the distributions for each column use instances of copula.distribution."""
# Setup
distribution = 'copulas.univariate.gaussian_kde.GaussianKDE'
copula = GaussianMultivariate(distribution=distribution)
# Run
copula.fit(self.data)
# Check
assert copula.distribution == 'copulas.univariate.gaussian_kde.GaussianKDE'
for i, key in enumerate(self.data.columns):
assert copula.columns[i] == key
assert get_qualified_name(copula.univariates[i].__class__) == copula.distribution
expected_covariance = copula._get_covariance(self.data)
assert (copula.covariance == expected_covariance).all().all()
def test_fit_distribution_arg(self):
"""On fit, the distributions for each column use instances of copula.distribution."""
# Setup
distribution = 'copulas.univariate.kde.KDEUnivariate'
copula = GaussianMultivariate(distribution=distribution)
# Run
copula.fit(self.data)
# Check
assert copula.distribution == 'copulas.univariate.kde.KDEUnivariate'
for key in self.data.columns:
assert key in copula.distribs
assert get_qualified_name(
copula.distribs[key].__class__) == copula.distribution
expected_covariance = copula._get_covariance(self.data)
assert (copula.covariance == expected_covariance).all().all()
def _sample_model(model, num_rows, columns):
"""Sample from model and format into pandas.DataFrame.
Args:
model(copula.multivariate.base): Fitted model.
num_rows(int): Number of rows to sample.
columns(Iterable): Column names for the sampled rows.
Returns:
pd.DataFrame: Sampled rows.
"""
if get_qualified_name(model) == 'copulas.multivariate.vine.VineCopula':
synthesized = [model.sample(num_rows).tolist() for row in range(num_rows)]
else:
synthesized = model.sample(num_rows)
return pd.DataFrame(synthesized, columns=columns)
def to_dict(self):
fitted = self.fitted
result = {
'tree_type': self.tree_type,
'type': get_qualified_name(self),
'fitted': fitted
}
if not fitted:
return result
result.update({
'level': self.level,
'n_nodes': self.n_nodes,
'tau_matrix': self.tau_matrix.tolist(),
'previous_tree': self._serialize_previous_tree(),
'edges': [edge.to_dict() for edge in self.edges],
})
return result
def test_fit_default_distribution(self):
"""On fit, a distribution is created for each column along the covariance and means"""
# Setup
copula = GaussianMultivariate()
# Run
copula.fit(self.data)
# Check
assert copula.distribution == 'copulas.univariate.gaussian.GaussianUnivariate'
for key in self.data.columns:
assert key in copula.distribs
assert get_qualified_name(
copula.distribs[key].__class__) == copula.distribution
assert copula.distribs[key].mean == self.data[key].mean()
assert copula.distribs[key].std == np.std(self.data[key])
expected_covariance = copula._get_covariance(self.data)
assert (copula.covariance == expected_covariance).all().all()
