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#!/usr/bin/env python
import pandas as pd
from sklearn.linear_model import SGDRegressor as _SGDRegressor
from sklearn.preprocessing import StandardScaler
import cexc
from codec import codecs_manager
from base import RegressorMixin, BaseAlgo
from util.param_util import convert_params
from util import df_util
from util.algo_util import add_missing_attr, get_kfold_cross_validation
messages = cexc.get_messages_logger()
class SGDRegressor(RegressorMixin, BaseAlgo):
def __init__(self, options):
self.handle_options(options)
out_params = convert_params(
options.get('params', {}),
bools=['fit_intercept'],
ints=['random_state', 'n_iter'],
floats=['l1_ratio', 'alpha', 'eta0', 'power_t'],
strs=['penalty', 'learning_rate'],
)
if 'eta0' in out_params and out_params['eta0'] < 0:
raise RuntimeError('eta0 must be equal to or greater than zero')
if 'learning_rate' in out_params:
if out_params['learning_rate'] in ("constant", "invscaling"):
if 'eta0' not in out_params:
out_params['eta0'] = 0.1
messages.warn(
'eta0 is not specified for learning_rate={}, defaulting to 0.1'.format(
out_params['learning_rate']
)
)
# Newer versions on sklearn have changed parameter 'n_iter' to 'n_iter_no_change'
# so we rename the parameter to keep the API
if 'n_iter' in out_params:
out_params['n_iter_no_change'] = out_params.pop('n_iter')
self.scaler = StandardScaler()
self.estimator = _SGDRegressor(**out_params)
self.columns = None
def fit(self, df, options):
# Make a copy of data, to not alter original dataframe
X = df.copy()
relevant_variables = self.feature_variables + [self.target_variable]
X, y, self.columns = df_util.prepare_features_and_target(
X=X,
variables=relevant_variables,
target=self.target_variable,
mlspl_limits=options.get('mlspl_limits'),
)
scaled_X = self.scaler.fit_transform(X.values)
# Return cross_validation scores if kfold_cv is set.
kfolds = options.get('kfold_cv')
if kfolds is not None:
cv_df = get_kfold_cross_validation(
estimator=self.estimator,
X=scaled_X,
y=y.values,
scoring=['r2', 'neg_mean_squared_error'],
kfolds=kfolds,
)
return cv_df
self.estimator.fit(scaled_X, y.values)
def partial_fit(self, df, options):
# Handle backwards compatibility.
add_missing_attr(self.estimator, attr='max_iter', value=5, param_key='n_iter')
add_missing_attr(self.estimator, attr='tol', value=None)
# Make a copy of data, to not alter original dataframe
X = df.copy()
relevant_variables = self.feature_variables + [self.target_variable]
X, y, columns = df_util.prepare_features_and_target(
X=X,
variables=relevant_variables,
target=self.target_variable,
mlspl_limits=options.get('mlspl_limits'),
)
if self.columns is not None:
X, y = df_util.handle_new_categorical_values(X, y, options, self.columns)
if X.empty:
return
else:
self.columns = columns
self.scaler.partial_fit(X.values)
scaled_X = self.scaler.transform(X.values)
self.estimator.partial_fit(scaled_X, y)
cexc.messages.warn('n_iter is set to 1 when partial fit is performed')
def apply(self, df, options=None):
# Handle backwards compatibility.
add_missing_attr(self.estimator, attr='max_iter', value=5, param_key='n_iter')
add_missing_attr(self.estimator, attr='tol', value=None)
# Make a copy of data, to not alter original dataframe
X = df.copy()
X, nans, columns = df_util.prepare_features(
X=X,
variables=self.feature_variables,
final_columns=self.columns,
mlspl_limits=options.get('mlspl_limits'),
)
scaled_X = self.scaler.transform(X.values)
y_hat = self.estimator.predict(scaled_X)
default_name = 'predicted({})'.format(self.target_variable)
output_name = options.get('output_name', default_name)
output = df_util.create_output_dataframe(
y_hat=y_hat, nans=nans, output_names=output_name
)
df = df_util.merge_predictions(df, output)
return df
def summary(self, options):
if len(options) != 2: # only model name and mlspl_limits
raise RuntimeError(
'"%s" models do not take options for summarization' % self.__class__.__name__
)
df = pd.DataFrame(
{'feature': self.columns, 'coefficient': self.estimator.coef_.ravel()}
)
idf = pd.DataFrame({'feature': '_intercept', 'coefficient': self.estimator.intercept_})
return pd.concat([df, idf])
@staticmethod
def register_codecs():
from codec.codecs import SimpleObjectCodec
codecs_manager.add_codec('algos.SGDRegressor', 'SGDRegressor', SimpleObjectCodec)
codecs_manager.add_codec(
'sklearn.linear_model._stochastic_gradient', 'SGDRegressor', SimpleObjectCodec
)
codecs_manager.add_codec(
'sklearn.preprocessing._data', 'StandardScaler', SimpleObjectCodec
)