def set_rf_samples(n):
""" Changes Scikit learn's random forests to give each tree a random sample of
n random rows.
"""
forest._generate_sample_indices = (
lambda rs, n_samples: forest.check_random_state(rs).randint(
0, n_samples, n))
yield
forest._generate_sample_indices = (
lambda rs, n_samples: forest.check_random_state(rs).randint(
0, n_samples, n_samples))
def set_rf_samples(n):
""" Changes Scikit learn's random forests to give each tree a random sample of
n random rows.
"""
forest._generate_sample_indices = (
lambda rs, n_samples: forest.check_random_state(rs).choice(
n_samples, n, replace=False))
def jeremy_trick_RF_sample_size(n):
# Jeremy's trick; hmm.. this won't work as a separate function?
# def batch_size_for_node_splitting(rs, n_samples):
# forest.check_random_state(rs).randint(0, n_samples, 20000)
# forest._generate_sample_indices = batch_size_for_node_splitting
forest._generate_sample_indices = \
(lambda rs, n_samples: forest.check_random_state(rs).randint(0, n_samples, n))
def set_rf_samples(n):
""" Changes Scikit-learn's random forests to give each tree a random sample of
n random rows.
Set oob_error in RandomForestRegressor to False if using this.
"""
forest._generate_sample_indices = (lambda rs, n_samples:
forest.check_random_state(rs).randint(0, n_samples, n))
def jeremy_trick_RF_sample_size(n):
# Jeremy's trick; hmm.. this won't work as a separate function?
# def batch_size_for_node_splitting(rs, n_samples):
# forest.check_random_state(rs).randint(0, n_samples, 20000)
# forest._generate_sample_indices = batch_size_for_node_splitting
forest._generate_sample_indices = \
(lambda rs, n_samples: forest.check_random_state(rs).randint(0, n_samples, n))
def set_random_forest_sample_size(nobs):
"""
Override default behavior of scikit-learn random forest models to
sample the same number of rows from the original data with replacement.
Instead, this forces random forest to fit each tree on a sample of size
nobs, greatly speeding up the algorithm on large datasets.
"""
forest.generate_sample_indices = (
lambda rs, n_samples: forest.check_random_state(rs).randint(
0, n_samples, nobs))
def reset_random_forest_sample_size():
"""
Restore the default behavior of scikit-learn random forest models to
sample the same number of rows from the original data with replacement.
This should be used if `set_random_forest_sample_size()` had been
previously run.
"""
forest.generate_sample_indices = (
lambda rs, n_samples: forest.check_random_state(rs).randint(
0, n_samples, n_samples))
def _generate_sample_indices_Peter(random_state, n_samples,n_bootstrap=None , y=None):
"""Private function used to _parallel_build_trees function."""
random_instance = check_random_state(random_state)
if n_bootstrap is None:
sample_indices = random_instance.randint(0, n_samples, n_samples)
else:
if y is None:
sample_indices = random_instance.randint(0, n_samples, n_bootstrap)
else:
sample_indices_y_0 = np.where( y == 0 )[0]
sample_indices_y_1 = np.where( y != 0 )[0]
xxx = list(sample_indices_y_0)
yyy = list(sample_indices_y_1)
random.shuffle(xxx)
random.shuffle(yyy)
sample_indices_y_0 = np.array(xxx)[0:(n_bootstrap/2)]
sample_indices_y_1 = np.array(yyy)[0:(n_bootstrap/2)]
sample_indices = np.array( list(sample_indices_y_0) + list(sample_indices_y_1) )
random.shuffle(sample_indices)
return sample_indices
def reset_rf_samples():
""" Undoes the changes produced by set_rf_samples.
"""
forest._generate_sample_indices = (
lambda rs, n_samples: forest.check_random_state(rs).randint(
0, n_samples, n_samples))
def jeremy_trick_reset_RF_sample_size():
forest._generate_sample_indices = (
lambda rs, n_samples: forest.check_random_state(rs).randint(
0, n_samples, n_samples))
def reset_rf_samples():
forest._generate_sample_indices = (
lambda rs, n_samples: forest.check_random_state(rs).randint(
0, n_samples, n_samples))
def reset_rf_samples():
""" Undoes the changes produced by set_rf_samples.
"""
forest._generate_sample_indices = (lambda rs, n_samples:
forest.check_random_state(rs).randint(0, n_samples, n_samples))
def set_rf_samples(n):
""" Changes Scikit learn's random forests to give each tree a random sample of
n random rows.
"""
forest._generate_sample_indices = (lambda rs, n_samples:
forest.check_random_state(rs).randint(0, n_samples, n))
def jeremy_trick_reset_RF_sample_size():
forest._generate_sample_indices = (lambda rs, n_samples:
forest.check_random_state(rs).randint(0, n_samples, n_samples))
def rf_reg_crossval(df, y, df_ts, n_months, n_days, n_est, min_sam_leaf):
n_folds = int(n_months * 30.0 / n_days)
errors = []
fis = []
first_dt_train = df.date.min(
) # First date available in the training set (train.csv)
#Setting seed
np.random.seed(9001)
#Sequentially split available training dataset into train and validation sets
for i in range(1, n_folds):
print('*____________________________________*')
print('running fold # ', i, ' of ', n_folds)
forest._generate_sample_indices = (
lambda rs, n_samples: forest.check_random_state(rs).randint(
0, n_samples, 1000000))
# Initialize random forest
m_kcv = RandomForestRegressor(n_estimators=n_est,
max_features=0.5,
min_samples_leaf=min_sam_leaf,
n_jobs=-1,
oob_score=False)
# Getting dates for training and validation sets
train_sub_startdt = first_dt_train + relativedelta(days=i * n_days)
valid_sub_startdt = first_dt_train + relativedelta(days=(i + 1) *
n_days)
# Create indices for training and validation sets
index_train = sorted(
df.index[df['date'] == train_sub_startdt].tolist())[0]
index_valid = sorted(
df.index[df['date'] == valid_sub_startdt].tolist())[0]
# Create subsetted dataframes of X,y, and w for training and validation sets
X_train, X_valid = split_vals(df.loc[:, df.columns != 'date'],
index_train, index_valid)
y_train, y_valid = split_vals(y, index_train, index_valid)
print('X train shape: ', X_train.shape)
print('Y train shape: ', y_train.shape)
print('X validation shape: ', X_valid.shape)
print('Y validation shape: ', y_valid.shape)
# Compute arrays of item score weights for the items in the validation
# set (for which we will make predictions)
item_weight_train = 1 + X_train['perishable'] * 0.25
item_weight_valid = 1 + X_valid['perishable'] * 0.25
# Optimizing the model fit by converting it to float array outside
X_train = np.array(X_train, dtype=np.float32)
# Fit the random forest model on training set w/ cross validation
m_kcv.fit(X_train, y_train)
# Print the NWRMSLE score and R-squared values for training and validation sets
train_score = prediction_score(m_kcv,
X_train,
y_train,
item_weight_train,
plot_pre=False)
val_score = prediction_score(m_kcv,
X_valid,
y_valid,
item_weight_valid,
plot_pre=False)
print('For training set: [nwrmsle, rsquared]: ', train_score)
print('For validation set: [nwrmsle, rsquared]: ', val_score)
print('\n')
# Add errors to the errors list
errors.append([train_score, val_score])
# Feature importance
fi = pd.DataFrame({
'col_names': df.loc[:, df.columns != 'date'].columns,
'feature_imp': m_kcv.feature_importances_
}).sort_values('feature_imp', ascending=False)
print(fi[:10])
fis.append(fi[:10])
# Reducing number of features
to_keep = fi[fi.feature_imp > 0.005].col_names
# we nedd to keep perishable for scoring
df_keep = df[to_keep].copy()
# Training on training set again
# Create subsetted dataframes of X,y, and w for training and validation sets
X_train, X_valid = split_vals(
df_keep.loc[:, df_keep.columns != 'date'], index_train,
index_valid)
y_train, y_valid = split_vals(y, index_train, index_valid)
print('\nTraining again on selected features')
print('X train shape: ', X_train.shape)
print('Y train shape: ', y_train.shape)
print('X validation shape: ', X_valid.shape)
print('Y validation shape: ', y_valid.shape)
# Compute arrays of item score weights for the items in the validation set (for which we will make predictions)
item_weight_train = 1 + X_train['perishable'] * 0.25
item_weight_valid = 1 + X_valid['perishable'] * 0.25
# Optimizing the model fit by converting it to float array outside
X_train = np.array(X_train, dtype=np.float32)
# Fit the random forest model on training set w/ cross validation
m_kcv.fit(X_train, y_train)
# Print the NWRMSLE score and R-squared values for training and validation sets
train_score = prediction_score(m_kcv,
X_train,
y_train,
item_weight_train,
plot_pre=False)
val_score = prediction_score(m_kcv,
X_valid,
y_valid,
item_weight_valid,
plot_pre=True)
print(
'For training set after feature selection : [nwrmsle, rsquared]: ',
train_score)
print(
'For validation set after feature selection: [nwrmsle, rsquared]: ',
val_score)
# Add errors to the errors list
errors.append([train_score, val_score])
# Train on entire training set
# Initialize random forest
m_kcv_new = RandomForestRegressor(n_estimators=n_est,
max_features=0.5,
min_samples_leaf=min_sam_leaf,
n_jobs=-1,
oob_score=False)
X_train_new = df_keep.loc[:, df_keep.columns != 'date'][:index_valid]
y_train_new = y[:index_valid]
# Compute arrays of item score weights for the items in the training
# set (for which we will make predictions)
item_weight_train_new = 1 + X_train_new['perishable'] * 0.25
# Optimizing the model fit by converting it to float array outside
X_train_new = np.array(X_train_new, dtype=np.float32)
print('\nTraining again on whole training set with selected features')
print('X train shape: ', X_train_new.shape)
print('Y train shape: ', y_train_new.shape)
# Fit the random forest model on training set w/ cross validation
m_kcv_new.fit(X_train_new, y_train_new)
# Print the NWRMSLE score and R-squared values for training and validation sets
train_score = prediction_score(m_kcv_new,
X_train_new,
y_train_new,
item_weight_train_new,
plot_pre=False)
print(
'For whole training set after feature selection : [nwrmsle, rsquared]: ',
train_score)
# # test set
# test_keep = df_ts[to_keep].copy()
#
# print('\nTesting on test data')
# #Predict for test set
# pred_test_log = m_kcv_new.predict(test_keep)
# pred_test = np.round(np.expm1(pred_test_log), decimals=0)
# output = pd.concat([test_keep['id'], pd.DataFrame(pred_test)], axis=1)
# output.columns = ['id', 'unit_sales']
# name = 'prediction' + str(i) + '.csv'
# output.to_csv(name, index=False)
# Write errors to file
with open('errors_rf_reg.txt', 'w') as file:
file.write(str(errors))
# Write feature importances to file
with open('feature_importance_rf_reg.txt', 'w') as file:
file.write(str(fis))
def fit(self, X, y, sample_weight=None):
"""Build a forest of trees from the training set (X, y).
Parameters
----------
X : array-like or sparse matrix of shape = [n_samples, n_features]
The training input samples. Internally, it will be converted to
``dtype=np.float32`` and if a sparse matrix is provided
to a sparse ``csc_matrix``.
y : array-like, shape = [n_samples] or [n_samples, n_outputs]
The target values (class labels in classification, real numbers in
regression).
sample_weight : array-like, shape = [n_samples] or None
Sample weights. If None, then samples are equally weighted. Splits
that would create child nodes with net zero or negative weight are
ignored while searching for a split in each node. In the case of
classification, splits are also ignored if they would result in any
single class carrying a negative weight in either child node.
Returns
-------
self : object
Returns self.
"""
# Validate or convert input data
X = check_array(X, dtype=DTYPE, accept_sparse="csc")
if issparse(X):
# Pre-sort indices to avoid that each individual tree of the
# ensemble sorts the indices.
X.sort_indices()
# Remap output
n_samples, self.n_features_ = X.shape
y = np.atleast_1d(y)
if y.ndim == 2 and y.shape[1] == 1:
warn("A column-vector y was passed when a 1d array was"
" expected. Please change the shape of y to "
"(n_samples,), for example using ravel().",
DataConversionWarning, stacklevel=2)
if y.ndim == 1:
# reshape is necessary to preserve the data contiguity against vs
# [:, np.newaxis] that does not.
y = np.reshape(y, (-1, 1))
self.n_outputs_ = y.shape[1]
y, expanded_class_weight = self._validate_y_class_weight(y)
if getattr(y, "dtype", None) != DOUBLE or not y.flags.contiguous:
y = np.ascontiguousarray(y, dtype=DOUBLE)
if expanded_class_weight is not None:
if sample_weight is not None:
sample_weight = sample_weight * expanded_class_weight
else:
sample_weight = expanded_class_weight
# Check parameters
self._validate_estimator()
if not self.bootstrap and self.oob_score:
raise ValueError("Out of bag estimation only available"
" if bootstrap=True")
random_state = check_random_state(self.random_state)
if not self.warm_start:
# Free allocated memory, if any
self.estimators_ = []
n_more_estimators = self.n_estimators - len(self.estimators_)
if n_more_estimators < 0:
raise ValueError('n_estimators=%d must be larger or equal to '
'len(estimators_)=%d when warm_start==True'
% (self.n_estimators, len(self.estimators_)))
elif n_more_estimators == 0:
warn("Warm-start fitting without increasing n_estimators does not "
"fit new trees.")
else:
if self.warm_start and len(self.estimators_) > 0:
# We draw from the random state to get the random state we
# would have got if we hadn't used a warm_start.
random_state.randint(MAX_INT, size=len(self.estimators_))
trees = []
for i in range(n_more_estimators):
tree = self._make_estimator(append=False)
tree.set_params(random_state=random_state.randint(MAX_INT))
trees.append(tree)
# Parallel loop: we use the threading backend as the Cython code
# for fitting the trees is internally releasing the Python GIL
# making threading always more efficient than multiprocessing in
# that case.
trees = Parallel(n_jobs=self.n_jobs, verbose=self.verbose,
backend="threading")(
delayed(_parallel_build_trees_Peter)(
t, self, X, y, sample_weight, i, len(trees),
verbose=self.verbose, class_weight=self.class_weight, n_bootstrap=self.n_bootstrap)
for i, t in enumerate(trees))
# Collect newly grown trees
self.estimators_.extend(trees)
if self.oob_score:
self._set_oob_score(X, y)
# Decapsulate classes_ attributes
if hasattr(self, "classes_") and self.n_outputs_ == 1:
self.n_classes_ = self.n_classes_[0]
self.classes_ = self.classes_[0]
return self
