def test_add_features_with_index():
X, y = make_classification(n_samples=1000,
n_features=100,
n_informative=2,
n_redundant=0,
n_repeated=0,
n_classes=2,
n_clusters_per_class=1,
weights=None,
class_sep=1.0,
hypercube=True,
scale=2.0,
shuffle=True,
random_state=0)
X_og = X.copy()
index = [0, 8, 9, 20]
X_two_less = np.delete(X_og, index, axis=1)
nb = CustomNaiveBayes(encode_data=True)
nb.fit(X_two_less, y)
nb.add_features(X_og[:, index], y, index=index)
independent = nb.indepent_term_
smoothed_log_counts_ = nb.smoothed_log_counts_
added = nb.predict_proba(X)
nb.fit(X, y)
og = nb.predict_proba(X)
assert np.allclose(nb.indepent_term_, independent)
assert np.allclose(nb.smoothed_log_counts_, smoothed_log_counts_)
assert np.allclose(og, added)
def test_remove_feature():
X, y = make_classification(n_samples=1000,
n_features=100,
n_informative=2,
n_redundant=0,
n_repeated=0,
n_classes=2,
n_clusters_per_class=1,
weights=None,
class_sep=1.0,
hypercube=True,
scale=2.0,
shuffle=True,
random_state=0)
nb = CustomNaiveBayes(encode_data=True)
nb.fit(X, y)
nb.remove_feature(0)
independent = nb.indepent_term_
smoothed_log_counts_ = nb.smoothed_log_counts_
removed = nb.predict_proba(np.delete(X, 0, axis=1))
nb.fit(np.delete(X, 0, axis=1), y)
og = nb.predict_proba(np.delete(X, 0, axis=1))
assert np.allclose(nb.smoothed_log_counts_, smoothed_log_counts_)
assert np.allclose(nb.indepent_term_, independent)
assert np.allclose(og, removed)
class GeneticProgrammingFlexibleLogic(OptimizationMixin, TransformerMixin,
ClassifierMixin, BaseEstimator):
"""GeneticProgramming for Feature Construction and Selection.
Parameters
----------
seed : int or None
Seed to guarantee reproducibility
individuals : int
Number of individuals per population
generations : int
Number of generations
mutation_probability : float
Probability for each individual of being mutated
select : {rank,proportionate}
Selection strategy
mutation : {simple,complex}
Mutation strategy
combine : {truncation,elitism}
Population combination strategy
n_intervals : int
Number of intervals for the discretization of continous variables
mixed : bool
Mix heuristic and wrapper evaluation
mixed_percentage : float
Percentage of total iterations to do heuristic evaluation
metric : {accuracy,f1-score}
Target metric for the optimization process
flexible_logic: bool
Allow different individual sizes in the generation
encode_data : bool, default=True
Encode data when data is not encoded by default with an OrdinalEncoder
verbose :int {0,1}, default = 1
Display process progress
Attributes
----------
classifier_ : NaiveBayes
Base classifier used for prediction
best_features_ : array-lik of Feature
Array of selected Feature used for transforming new data
"""
def simple_evaluate(self, individual, X, y):
classifier_ = NaiveBayes(encode_data=False, metric=self.metric)
return classifier_.leave_one_out_cross_val(transform_features(
individual[0] + individual[1], X),
y,
fit=True)
def simple_evaluate_heuristic(self, individual, X, y):
return compute_sufs_non_incremental(
features=[f.transform(X) for f in chain(*individual[:2])], y=y)
def fitness(self, population, X, y):
evaluation = []
for individual in population:
evaluation.append((individual, self.evaluate(individual, X, y)))
return evaluation
def generate_population(self):
population = []
for _ in range(self.individuals):
individual = ([], [], set())
if self.flexible_logic:
n_chromosomes = range(random.randint(1, self.size))
else:
n_chromosomes = range(self.size)
for _ in n_chromosomes:
operand1_feature = random.randint(0, self.n_features - 1)
operand2_feature = random.randint(0, self.n_features - 1)
if operand1_feature == operand2_feature:
op = 'OR'
operand1_value = random.randint(
0, self.unique_values[operand1_feature] - 1)
operand2_value = random.randint(
0, self.unique_values[operand1_feature] - 1)
else:
op = random.choice(('OR', 'XOR', 'AND'))
operand1_value = random.randint(
0, self.unique_values[operand1_feature] - 1)
operand2_value = random.randint(
0, self.unique_values[operand2_feature] - 1)
operands = []
operands.append((operand1_feature, operand1_value))
operands.append((operand2_feature, operand2_value))
individual[1].append(
create_feature(operator=op, operands=operands))
n_og_features = random.randint(0, self.n_features - 1)
features = list(range(self.n_features))
for f in random.sample(features, n_og_features):
individual[0].append(DummyFeatureConstructor(feature_index=f))
individual[2].add(f)
population.append(individual)
return population
def mutate_complex(self, population, **kwargs):
new_population = []
for individual in population:
if random.random() < self.mutation_probability:
chromosomes_index = []
if self.flexible_logic:
if len(individual[1]) > 0:
chromosomes_index = random.sample(
list(range(len(individual[1]))),
random.randint(1, len(individual[1])))
else:
op = random.choice(('OR', 'XOR', 'AND'))
operands = []
for _ in range(2):
feature_index = random.randint(
0, self.n_features - 1)
value = random.randint(
0, self.unique_values[feature_index] - 1)
operands.append((feature_index, value))
individual[1].append(
create_feature(operator=op, operands=operands))
new_population.append(individual)
continue
else:
chromosomes_index = random.sample(
list(range(len(individual[1]))),
random.randint(1, len(individual[1])))
for i in range(len(chromosomes_index)):
index = chromosomes_index[i]
if not self.flexible_logic:
feature = individual[1][index]
feature.op = random.choice(('OR', 'XOR', 'AND'))
for operand in feature.operands:
operand.feature_index = random.randint(
0, self.n_features - 1)
operand.value = random.randint(
0,
self.unique_values[operand.feature_index] - 1)
else:
a = random.random()
if a < 0.33:
feature = individual[1][index]
feature.op = random.choice(('OR', 'XOR', 'AND'))
for operand in feature.operands:
operand.feature_index = random.randint(
0, self.n_features - 1)
operand.value = random.randint(
0,
self.unique_values[operand.feature_index] -
1)
elif a < 0.66:
op = random.choice(('OR', 'XOR', 'AND'))
operands = []
for _ in range(2):
feature_index = random.randint(
0, self.n_features - 1)
value = random.randint(
0, self.unique_values[feature_index] - 1)
operands.append((feature_index, value))
individual[1].append(
create_feature(operator=op, operands=operands))
else:
del individual[1][index]
chromosomes_index = [
j - 1 if j > index else j
for j in chromosomes_index
]
if random.random() < self.mutation_probability:
a = random.random()
og_features = individual[0]
included_features = individual[2]
if (a < 0.33 and len(og_features) < self.n_features
) or len(og_features) == 0:
selected = random.choice(
tuple(
set(list(range(0, self.n_features))) -
included_features))
included_features.add(selected)
og_features.append(DummyFeatureConstructor(selected))
elif a < 0.66 and len(og_features) < self.n_features and len(
og_features) > 0:
selected = random.choice(
tuple(
set(list(range(0, self.n_features))) -
included_features))
index = random.randint(0, len(og_features) - 1)
feature = og_features[index].feature_index
og_features[index] = DummyFeatureConstructor(selected)
included_features.remove(feature)
included_features.add(selected)
else:
index = random.randint(0, len(og_features) - 1)
feature = og_features[index].feature_index
del og_features[index]
included_features.remove(feature)
if len(individual[0]) == 0 and len(individual[1]) == 0:
og_features = individual[0]
included_features = individual[2]
selected = random.choice(
tuple(
set(list(range(0, self.n_features))) -
included_features))
included_features.add(selected)
og_features.append(DummyFeatureConstructor(selected))
new_population.append(individual)
return new_population
def mutate_simple(self, population, **kwargs):
new_population = []
for individual in population:
if random.random() < self.mutation_probability:
chromosomes_index = []
if self.flexible_logic:
if len(individual[1]) > 0:
chromosomes_index = random.sample(
list(range(len(individual[1]))),
random.randint(1, len(individual[1])))
else:
op = random.choice(('OR', 'XOR', 'AND'))
operands = []
for _ in range(2):
feature_index = random.randint(
0, self.n_features - 1)
value = random.randint(
0, self.unique_values[feature_index] - 1)
operands.append((feature_index, value))
individual[1].append(
create_feature(operator=op, operands=operands))
new_population.append(individual)
continue
else:
chromosomes_index = random.sample(
list(range(len(individual[1]))),
random.randint(1, len(individual[1])))
for i in range(len(chromosomes_index)):
index = chromosomes_index[i]
feature = individual[1][index]
if not self.flexible_logic:
feature.op = random.choice(('OR', 'XOR', 'AND'))
for operand in feature.operands:
operand.feature_index = random.randint(
0, self.n_features - 1)
operand.value = random.randint(
0,
self.unique_values[operand.feature_index] - 1)
else:
a = random.random()
if a < 0.33:
b = random.random()
if b < 0.2:
# Change operatior
feature.op = random.choice(
('OR', 'XOR', 'AND'))
elif b < 0.4:
# Change full operand
operand = feature.operands[0]
operand.value = random.randint(
0,
self.unique_values[operand.feature_index] -
1)
elif b < 0.6:
# Change full operand
operand = feature.operands[1]
operand.value = random.randint(
0,
self.unique_values[operand.feature_index] -
1)
elif b < 0.8:
# Change value
operand = feature.operands[0]
operand.value = random.randint(
0,
self.unique_values[operand.feature_index] -
1)
else:
# Change value
operand = feature.operands[1]
operand.value = random.randint(
0,
self.unique_values[operand.feature_index] -
1)
elif a < 0.66:
# Add feature
op = random.choice(('OR', 'XOR', 'AND'))
operands = []
for _ in range(2):
feature_index = random.randint(
0, self.n_features - 1)
value = random.randint(
0, self.unique_values[feature_index] - 1)
operands.append((feature_index, value))
individual[1].append(
create_feature(operator=op, operands=operands))
else:
# Remove feature
del individual[1][index]
chromosomes_index = [
j - 1 if j > index else j
for j in chromosomes_index
]
if random.random() < self.mutation_probability:
a = random.random()
og_features = individual[0]
included_features = individual[2]
if (a < 0.33 and len(og_features) < self.n_features
) or len(og_features) == 0:
selected = random.choice(
tuple(
set(list(range(0, self.n_features))) -
included_features))
included_features.add(selected)
og_features.append(DummyFeatureConstructor(selected))
elif a < 0.66 and len(og_features) < self.n_features and len(
og_features) > 0:
selected = random.choice(
tuple(
set(list(range(0, self.n_features))) -
included_features))
index = random.randint(0, len(og_features) - 1)
feature = og_features[index].feature_index
og_features[index] = DummyFeatureConstructor(selected)
included_features.remove(feature)
included_features.add(selected)
else:
index = random.randint(0, len(og_features) - 1)
feature = og_features[index].feature_index
del og_features[index]
included_features.remove(feature)
if len(individual[0]) == 0 and len(individual[1]) == 0:
og_features = individual[0]
included_features = individual[2]
selected = random.choice(
tuple(
set(list(range(0, self.n_features))) -
included_features))
included_features.add(selected)
og_features.append(DummyFeatureConstructor(selected))
new_population.append(individual)
return new_population
def elitism(self, population1, population2):
maximum = max(population1, key=lambda x: x[1])
minimum_index = min(enumerate(population2), key=lambda x: x[1][1])[0]
population2[minimum_index] = maximum
return population2
def truncation(self, population1, population2):
return sorted(population1 + population2,
reverse=True,
key=lambda x: x[1])[:len(population1)]
def select_population(self, population):
selected_individuals = []
num_selected = len(population)
totalFitness = sum(fitness for _, fitness in population)
for _ in range(num_selected):
cumulative_prob = 0.0
r = random.random()
for individual_with_fitness in population:
cumulative_prob += individual_with_fitness[1] / totalFitness
if r <= cumulative_prob:
selected_individuals.append(
self.copy_individual(individual_with_fitness[0]))
break
return selected_individuals
def select_population_rank(self, population):
selected_individuals = []
num_selected = len(population)
totalRank = (num_selected * (num_selected + 1)) / 2
population.sort(reverse=True, key=lambda x: x[1])
for _ in range(num_selected):
cumulative_prob = 0.0
r = random.random()
for i, individual_with_fitness in enumerate(population, start=1):
cumulative_prob += (num_selected - i + 1) / totalRank
if r <= cumulative_prob:
selected_individuals.append(
self.copy_individual(individual_with_fitness[0]))
break
return selected_individuals
def copy_individual(self, individual):
return ([chrms.copy() for chrms in individual[0]],
[chrms.copy()
for chrms in individual[1]], individual[2].copy())
def fit(self, X, y):
self.feature_encoder_ = CustomOrdinalFeatureEncoder()
self.class_encoder_ = CustomLabelEncoder()
if isinstance(X, pd.DataFrame):
self.categories_ = X.columns
if self.encode_data:
X = self.feature_encoder_.fit_transform(X)
y = self.class_encoder_.fit_transform(y)
classifier_ = NaiveBayes(encode_data=False,
n_intervals=self.n_intervals,
metric=self.metric)
self.n_features = X.shape[1]
if self.encode_data:
self.unique_values = [
values.shape[0] for values in self.feature_encoder_.categories_
]
else:
self.unique_values = [
np.unique(X[:, j]).shape[0] for j in range(X.shape[1])
]
random.seed(self.seed)
np.random.seed(self.seed)
self.size = np.ceil(np.sqrt(X.shape[1]))
best_individual = self.execute_algorithm(X, y)
self.best_features = best_individual
self.classifier_ = NaiveBayes(encode_data=False, metric=self.metric)
self.classifier_.fit(
np.concatenate(
[feature.transform(X) for feature in self.best_features],
axis=1), y)
return self
def execute_algorithm(self, X, y):
if self.mixed:
self.evaluate = self.evaluate_heuristic
else:
self.evaluate = self.evaluate_wrapper
population = self.generate_population()
population_with_fitness = self.fitness(population, X, y)
iterator = tqdm(range(self.generations),
leave=False) if self.verbose else range(
self.generations)
for generation in iterator:
if self.mixed and generation > int(
self.generations * self.mixed_percentage
) and self.evaluate == self.evaluate_heuristic:
self.evaluate = self.evaluate_wrapper
# Reevaluate for fair combination
population_with_fitness = self.fitness([
individual_with_fitness[0]
for individual_with_fitness in population_with_fitness
], X, y)
selected_individuals = self.selection(population_with_fitness)
crossed_individuals = selected_individuals # self.crossover(selected_individuals)
mutated_individuals = self.mutation(crossed_individuals, X=X, y=y)
new_population = self.fitness(mutated_individuals, X, y)
population_with_fitness = self.combine(population_with_fitness,
new_population)
# Obtaining population's statistics
if self.verbose:
best, mean = get_max_mean(population_with_fitness)
iterator.set_postfix({
"Generation":
generation,
"hit_count":
self.evaluate.hit_count,
"populationLength":
len(population_with_fitness),
"best fitness":
best,
"mean fitness":
mean
})
best_individual = max(population_with_fitness, key=lambda x: x[1])[0]
return best_individual[0] + best_individual[1]
def reset_evaluation(self):
self.evaluate_wrapper = memoize_genetic(self.simple_evaluate)
self.evaluate_heuristic = memoize_genetic(
self.simple_evaluate_heuristic)
def set_params(self, **params):
super().set_params(**params)
if "selection" in params:
if params["selection"] not in ("rank", "proportionate"):
raise ValueError(
"Unknown selection parameter expected one of : " +
str(tuple(["rank", "proportionate"])))
self.selection = self.select_population_rank if "rank" in params[
"selection"] else self.select_population
if "combine" in params:
if params["combine"] not in ("elitism", "truncate"):
raise ValueError(
"Unknown selection parameter expected one of : " +
str(tuple(["elitism", "truncate"])))
self.combine = self.elitism if "elit" in params[
"combine"] else self.truncation
if "mutation" in params:
if params["mutation"] not in ("complex", "simple"):
raise ValueError(
"Unknown selection parameter expected one of : " +
str(tuple(["complex", "simple"])))
self.mutation = self.mutate_simple if "simple" == params[
"mutation"] else self.mutate_complex
def __init__(self,
seed=None,
individuals=1,
generations=40,
mutation_probability=0.2,
selection="rank",
mutation="simple",
combine="elitism",
n_intervals=5,
metric="accuracy",
flexible_logic=True,
verbose=False,
encode_data=True,
mixed=True,
mixed_percentage=0.5):
self.mixed_percentage = mixed_percentage
self.mixed = mixed
self.encode_data = encode_data
self.flexible_logic = flexible_logic
self.verbose = verbose
self.n_intervals = n_intervals
self.metric = metric
self.seed = seed
self.individuals = individuals
self.generations = generations
self.mutation_probability = mutation_probability
self.selection = selection
self.combine = combine
self.mutation = mutation
allowed_selection = ('rank', 'proportionate')
allowed_combine = ('elitism', 'truncate')
allowed_mutation = ('complex', 'simple')
if self.selection not in allowed_selection:
raise ValueError(
"Unknown selection type: %s, expected one of %s." %
(self.selection, selection))
if self.combine not in allowed_combine:
raise ValueError("Unknown combine type: %s, expected one of %s." %
(self.combine, combine))
if self.mutation not in allowed_mutation:
raise ValueError(
"Unknown selection type: %s, expected one of %s." %
(self.mutation, mutation))
self.selection = self.select_population_rank if "rank" in selection else self.select_population
self.combine = self.elitism if "elit" in combine else self.truncation
self.mutation = self.mutate_simple if "simple" in mutation else self.mutate_complex
self.reset_evaluation()
def acfs_score_comparison(datasets,
seed,
base_path,
params,
n_splits=3,
n_repeats=5,
n_intervals=5,
metric="accuracy",
send_email=False,
email_data=dict(),
verbose=True):
# List to store results and column names for the csv
result = []
columns = [
"Database", "Number of attributes", "NBScore", "NBScore STD",
"ACFCS Score", "ACFCS Score STD", "Configuration", "Nodes",
"Contruction Matrix", "Selection Matrix", "Selected_attributes",
"Original"
]
dataset_tqdm = tqdm(datasets)
# Instantiate the classifier
acfcs = ACFCS(verbose=0, metric=metric)
nb = NaiveBayes(encode_data=False, n_intervals=n_intervals, metric=metric)
# Execute algorithm on datasets
for database in dataset_tqdm:
name, label = database
if not os.path.exists(base_path + name):
print(f"{name} doesnt' exist")
continue
# Assume UCI REPO like data
test = f"{name}.test.csv"
data = f"{name}.data.csv"
X, y = get_X_y_from_database(base_path, name, data, test, label)
# Update progressbar
dataset_tqdm.set_postfix({"DATABASE": name})
# Set up data structures to store results
nb_score = np.zeros(shape=(len(params), n_splits * n_repeats))
acfcs_score = np.zeros(shape=(len(params), n_splits * n_repeats))
acfcs_selection_matrix = np.zeros(shape=(len(params),
n_splits * n_repeats))
acfcs_construction_matrix = np.zeros(shape=(len(params),
n_splits * n_repeats))
acfcs_nodes = np.zeros(shape=(len(params), n_splits * n_repeats))
acfcs_dummy = np.zeros(shape=(len(params), n_splits * n_repeats))
acfcs_selected = np.zeros(shape=(len(params), n_splits * n_repeats))
# Create splits for the experiments
rskf = RepeatedStratifiedKFold(n_splits=n_splits,
n_repeats=n_repeats,
random_state=seed)
seed_tqdm = tqdm(rskf.split(X, y),
leave=False,
total=n_splits * n_repeats,
bar_format='{l_bar}{bar:20}{r_bar}{bar:-10b}'
) if verbose else rskf.split(X, y)
# Execute experiments
for i, data in enumerate(seed_tqdm):
train_index, test_index = data
X_train, X_test = X.iloc[train_index], X.iloc[test_index]
y_train, y_test = y.iloc[train_index], y.iloc[test_index]
# Encode the data
c = CustomOrdinalFeatureEncoder(n_intervals=n_intervals)
X_train = c.fit_transform(X_train)
X_test = c.transform(X_test)
l = CustomLabelEncoder()
y_train = l.fit_transform(y_train)
y_test = l.transform(y_test)
# Assess the classifiers reusing info to speed up evaluation
nb.fit(X_train, y_train)
naive_bayes_score = nb.score(X_test, y_test)
acfcs.reset_cache()
for conf_index, conf in enumerate(params):
acfcs.set_params(**conf)
acfcs.fit(X_train, y_train, init_graph=conf_index == 0)
# score
acfcs_score_conf = acfcs.score(X_test, y_test)
if verbose:
seed_tqdm.set_postfix({
"config": conf_index,
"nb_score": naive_bayes_score,
"ant_score": acfcs_score_conf
})
# Get data
n_original_features = len(
list(
filter(
lambda x: isinstance(x, DummyFeatureConstructor),
acfcs.best_features)))
n_selected = len(acfcs.best_features)
selection_matrix = len(acfcs.afg.pheromone_selection)
construction_matrix = len(acfcs.afg.pheromone_construction)
nodes = len(acfcs.afg.nodes)
# Update
nb_score[conf_index, i] = naive_bayes_score
acfcs_score[conf_index, i] = acfcs_score_conf
acfcs_selection_matrix[conf_index, i] = selection_matrix
acfcs_construction_matrix[conf_index, i] = construction_matrix
acfcs_nodes[conf_index, i] = nodes
acfcs_dummy[conf_index, i] = n_original_features
acfcs_selected[conf_index, i] = n_selected
# Insert the final result - averaged metrics for this database.
for conf_index, conf in enumerate(params):
row = [
name, X.shape[1],
np.mean(nb_score[conf_index]),
np.std(nb_score[conf_index]),
np.mean(acfcs_score[conf_index]),
np.std(acfcs_score[conf_index]), conf,
np.mean(acfcs_nodes[conf_index]),
np.mean(acfcs_construction_matrix[conf_index]),
np.mean(acfcs_selection_matrix[conf_index]),
np.mean(acfcs_selected[conf_index]),
np.mean(acfcs_dummy[conf_index])
]
result.append(row)
result = pd.DataFrame(result, columns=columns)
if send_email:
from tfg.utils import send_results
send_results("ACFCS", email_data, result)
return result
def ranker_score_comparison(datasets,
seed,
base_path,
params,
n_splits=3,
n_repeats=5,
n_intervals=5,
metric="accuracy",
send_email=False,
email_data=dict(),
share_rank=True):
result = []
columns = ["Database",
"Number of attributes",
"NBScore",
"NBScore STD",
"Ranker Score",
"Ranker Score STD",
"Configuration",
"Combinations",
"Selected_attributes",
"Original"]
dataset_tqdm = tqdm(datasets)
# Instantiate the classifier
r = RankerLogicalFeatureConstructor(n_intervals=n_intervals, metric=metric)
nb = NaiveBayes(encode_data=False, n_intervals=n_intervals, metric=metric)
# Execute algorithm on datasets
for database in dataset_tqdm:
name, label = database
if not os.path.exists(base_path + name):
print(f"{name} doesnt' exist")
continue
# Assume UCI REPO like data
test = f"{name}.test.csv"
data = f"{name}.data.csv"
X, y = get_X_y_from_database(base_path, name, data, test, label)
dataset_tqdm.set_postfix({"DATABASE": name})
# Set up data structures to store results
nb_score = np.zeros(shape=(len(params), n_splits*n_repeats))
r_score = np.zeros(shape=(len(params), n_splits*n_repeats))
r_combinations = np.zeros(shape=(len(params), n_splits*n_repeats))
r_selected = np.zeros(shape=(len(params), n_splits*n_repeats))
r_dummy = np.zeros(shape=(len(params), n_splits*n_repeats))
r_total_constructed = np.zeros(shape=(len(params), n_splits*n_repeats))
r_total_selected = np.zeros(shape=(len(params), n_splits*n_repeats))
r_original_selected = np.zeros(shape=(len(params), n_splits*n_repeats))
rskf = RepeatedStratifiedKFold(n_splits=n_splits, n_repeats=n_repeats, random_state=seed)
seed_tqdm = tqdm(rskf.split(X, y),
leave=False,
total=n_splits*n_repeats,
bar_format='{l_bar}{bar:20}{r_bar}{bar:-10b}')
for i, data in enumerate(seed_tqdm):
train_index, test_index = data
X_train, X_test = X.iloc[train_index], X.iloc[test_index]
y_train, y_test = y.iloc[train_index], y.iloc[test_index]
c = CustomOrdinalFeatureEncoder(n_intervals=n_intervals)
X_train = c.fit_transform(X_train)
X_test = c.transform(X_test)
l = CustomLabelEncoder()
y_train = l.fit_transform(y_train)
y_test = l.transform(y_test)
# Assess the classifiers
nb.fit(X=X_train, y=y_train)
naive_bayes_score = nb.score(X_test, y_test)
for conf_index, conf in enumerate(params):
seed_tqdm.set_postfix({"config": conf_index})
r.set_params(**conf)
# Fit
if conf_index == 0 or not share_rank:
# The rank is computed from scratch
r.fit(X_train, y_train)
else:
r.filter_features(r.feature_encoder_.transform(
X_train), r.class_encoder_.transform(y_train))
# score
ranker_score = r.score(X_test, y_test)
# Get data
n_original_features = len(list(filter(lambda x: isinstance(
x, DummyFeatureConstructor), r.final_feature_constructors)))
n_combinations = len(r.all_feature_constructors)
n_selected = len(r.final_feature_constructors)
# Update
nb_score[conf_index, i] = naive_bayes_score
r_score[conf_index, i] = ranker_score
r_combinations[conf_index, i] = n_combinations
r_selected[conf_index, i] = n_selected
r_dummy[conf_index, i] = n_original_features
# Insert to final result averaged metrics for this dataset
for conf_index, conf in enumerate(params):
row = [name,
X.shape[1],
np.mean(nb_score[conf_index]),
np.std(nb_score[conf_index]),
np.mean(r_score[conf_index]),
np.std(r_score[conf_index]),
conf,
np.mean(r_combinations[conf_index]),
np.mean(r_selected[conf_index]),
np.mean(r_dummy[conf_index])]
result.append(row)
result = pd.DataFrame(result, columns=columns)
if send_email:
from tfg.utils import send_results
send_results("RANKER", email_data, result)
return result
def fit(self, X, y):
# Parse input
if isinstance(y, pd.DataFrame):
y = y.to_numpy()
if self.encode_data:
self.feature_encoder_ = CustomOrdinalFeatureEncoder(
n_intervals=self.n_intervals)
self.class_encoder_ = CustomLabelEncoder()
X = self.feature_encoder_.fit_transform(X)
y = self.class_encoder_.fit_transform(y)
if isinstance(X, pd.DataFrame):
X = X.to_numpy()
check_X_y(X, y)
# Reset the stored results for new fit
self.reset_evaluation()
# Generate rank
if self.use_graph:
# Construct the minimum graph and create rank
graph = AntFeatureGraphMI(seed=None, connections=1).compute_graph(
X, y, ("AND", "OR", "XOR"))
self.all_feature_constructors = graph.get_rank()
elif self.prune is not None:
# Construct the rank with pruning by selecting pais that maximise SU(X_iX_j,Y)
feature_combinations = list(
combinations(list(range(X.shape[1])),
2)) + [(i, i) for i in range(X.shape[1])]
rank_pairs = [
symmetrical_uncertainty_two_variables(X[:, i], X[:, j], y)
for i, j in feature_combinations
]
rank_pairs_index = np.argsort(rank_pairs)[::-1]
# Create the unsorted list
self.all_feature_constructors = []
for index in rank_pairs_index[:self.prune]:
i, j = feature_combinations[index]
if i == j:
from tfg.feature_construction import create_feature
self.all_feature_constructors.extend([
create_feature("OR", [(i, n), (i, m)])
for n, m in combinations(np.unique(X[:, i]), 2)
])
else:
self.all_feature_constructors.extend(
construct_features(X[:, [i, j]],
operators=self.operators,
same_feature=False))
else:
# Create the unsorted list of all features
self.all_feature_constructors = construct_features(
X, operators=self.operators)
if self.verbose:
print(
f"Total number of constructed features: {len(self.all_feature_constructors)}"
)
self.all_feature_constructors.extend(
[DummyFeatureConstructor(j) for j in range(X.shape[1])])
self.symmetrical_uncertainty_rank = []
# Sort the ranking
for feature_constructor in self.all_feature_constructors:
feature = feature_constructor.transform(X)
su = symmetrical_uncertainty(f1=feature.flatten(), f2=y)
self.symmetrical_uncertainty_rank.append(su)
# Store the descending order index
self.rank = np.argsort(self.symmetrical_uncertainty_rank)[::-1]
# If the initial variables are
if self.use_initials:
classifier = NaiveBayes(encode_data=False,
n_intervals=self.n_intervals,
metric=self.metric)
classifier.fit(X, y)
current_features = [
DummyFeatureConstructor(j) for j in range(X.shape[1])
]
# Store the backward result to reuse it for other executions
self.initial_backward_features = backward_search(
X, y, current_features, classifier)
# Feature Subset Selection (FSS) from the rank
self.filter_features(X, y)
return self
def genetic_score_comparison(datasets,
seed,
base_path,
params,
n_splits=3,
n_repeats=5,
n_intervals=5,
metric="accuracy",
send_email=False,
email_data=dict(),
verbose=True,
version=1):
result = []
columns = [
"Database", "Number of attributes", "NBScore", "NBScore STD",
"Genetic Score", "Genetic Score STD", "Configuration",
"Selected_attributes", "Original"
]
dataset_tqdm = tqdm(datasets)
# Instantiate the classifier
if version == 1:
# First Version - No flexibility in the number of attributes (bad performance)
# clf = GeneticProgramming(seed=seed, metric=metric)
clf = GeneticProgrammingFlexibleLogic(seed=seed, metric=metric)
elif version == 2:
# Version with flexibility
clf = GeneticProgrammingFlexibleLogic(seed=seed, metric=metric)
else:
# Guided mutation based on SU
clf = GeneticProgrammingRankMutation(seed=seed, metric=metric)
nb = NaiveBayes(encode_data=False, n_intervals=n_intervals, metric=metric)
# Execute algorithm on datasets
for database in dataset_tqdm:
name, label = database
if not os.path.exists(base_path + name):
print(f"{name} doesnt' exist")
continue
# Assume UCI REPO like data
test = f"{name}.test.csv"
data = f"{name}.data.csv"
X, y = get_X_y_from_database(base_path, name, data, test, label)
dataset_tqdm.set_postfix({"DATABASE": name})
# Set up data structures to store results
nb_score = np.zeros(shape=(len(params), n_splits * n_repeats))
clf_score = np.zeros(shape=(len(params), n_splits * n_repeats))
clf_selected = np.zeros(shape=(len(params), n_splits * n_repeats))
clf_dummy = np.zeros(shape=(len(params), n_splits * n_repeats))
# Create splits for the experiments
rskf = RepeatedStratifiedKFold(n_splits=n_splits,
n_repeats=n_repeats,
random_state=seed)
seed_tqdm = tqdm(rskf.split(X, y),
leave=False,
total=n_splits * n_repeats,
bar_format='{l_bar}{bar:20}{r_bar}{bar:-10b}'
) if verbose else rskf.split(X, y)
# Execute experiments
for i, data in enumerate(seed_tqdm):
train_index, test_index = data
X_train, X_test = X.iloc[train_index], X.iloc[test_index]
y_train, y_test = y.iloc[train_index], y.iloc[test_index]
# Encode the data
c = CustomOrdinalFeatureEncoder(n_intervals=n_intervals)
X_train = c.fit_transform(X_train)
X_test = c.transform(X_test)
l = CustomLabelEncoder()
y_train = l.fit_transform(y_train)
y_test = l.transform(y_test)
# Assess the classifiers reusing info to speed up evaluation
nb.fit(X_train, y_train)
naive_bayes_score = nb.score(X_test, y_test)
# Reset evaluation-cache for new split
clf.reset_evaluation()
for conf_index, conf in enumerate(params):
if verbose:
seed_tqdm.set_postfix({"config": conf_index})
clf.set_params(**conf)
clf.fit(X_train, y_train)
# score
genetic_score = clf.score(X_test, y_test)
# Get data
n_original_features = len(
list(
filter(
lambda x: isinstance(x, DummyFeatureConstructor),
clf.best_features)))
n_selected = len(clf.best_features)
# Update
nb_score[conf_index, i] = naive_bayes_score
clf_score[conf_index, i] = genetic_score
clf_selected[conf_index, i] = n_selected
clf_dummy[conf_index, i] = n_original_features
# Insert to final result averaged metrics for this database
for conf_index, conf in enumerate(params):
row = [
name, X.shape[1],
np.mean(nb_score[conf_index]),
np.std(nb_score[conf_index]),
np.mean(clf_score[conf_index]),
np.std(clf_score[conf_index]), conf,
np.mean(clf_selected[conf_index]),
np.mean(clf_dummy[conf_index])
]
result.append(row)
result = pd.DataFrame(result, columns=columns)
if send_email:
from tfg.utils import send_results
send_results(f"GENETIC_{version}", email_data, result)
return result
class ACFCS(OptimizationMixin, TransformerMixin, ClassifierMixin,
BaseEstimator):
def __init__(self,
ants=10,
evaporation_rate=0.05,
intensification_factor=0.05,
alpha=1.0,
beta=0.0,
beta_evaporation_rate=0.05,
step=1,
iterations=100,
early_stopping=20,
update_strategy="best",
seed=None,
parallel=False,
save_features=False,
path=None,
filename=None,
verbose=0,
graph_strategy="mutual_info",
connections=2,
max_errors=0,
metric="accuracy",
use_initials=False,
final_selection="ALL",
encode_data=True):
self.step = step
self.ants = ants
self.evaporation_rate = evaporation_rate
self.intensification_factor = intensification_factor
self.alpha = alpha
self.beta = beta
self.beta_evaporation_rate = beta_evaporation_rate
self.iterations = iterations
self.early_stopping = early_stopping
self.seed = seed
self.parallel = parallel
self.save_features = save_features
self.path = path
self.filename = filename
self.verbose = verbose
self.graph_strategy = graph_strategy
self.connections = connections
self.metric = metric
self.update_strategy = update_strategy
self.use_initials = use_initials
self.final_selection = final_selection
self.encode_data = encode_data
self.max_errors = max_errors
allowed_graph_strategy = ("full", "mutual_info")
if self.graph_strategy not in allowed_graph_strategy:
raise ValueError(
"Unknown graph strategy type: %s, expected one of %s." %
(self.graph_strategy, allowed_graph_strategy))
allowed_update_strategy = ("all", "best")
if self.update_strategy not in allowed_update_strategy:
raise ValueError(
"Unknown graph strategy type: %s, expected one of %s." %
(self.update_strategy, allowed_update_strategy))
self.reset_cache()
def reset_cache(self):
self.cache_loo = dict()
self.cache_heuristic = dict()
def fit(self, X, y, init_graph=True):
self.feature_encoder_ = CustomOrdinalFeatureEncoder()
self.class_encoder_ = CustomLabelEncoder()
self.categories_ = None
if isinstance(X, pd.DataFrame):
self.categories_ = X.columns
if self.encode_data:
X = self.feature_encoder_.fit_transform(X)
y = self.class_encoder_.fit_transform(y)
if init_graph:
if self.graph_strategy == "full":
#Full graph
self.afg = AntFeatureGraph(seed=self.seed).compute_graph(
X, y, ("XOR", "OR", "AND"))
else:
#Pruned graph
self.afg = AntFeatureGraphMI(
seed=self.seed,
connections=self.connections).compute_graph(
X, y, ("XOR", "OR", "AND"))
else:
self.afg.reset_pheromones()
if self.verbose:
print(f"Number of nodes: {len(self.afg.nodes)}")
random.seed(self.seed)
best_score = 0
self.best_features = []
iterations_without_improvement = 0
iterator = tqdm(range(self.iterations)) if self.verbose else range(
self.iterations)
beta = self.beta
distance_from_best = -1
for iteration in iterator:
if self.verbose:
iterator.set_postfix({
"best_score":
best_score,
"n_features":
len(self.best_features),
"p_matrix_c":
len(self.afg.pheromone_construction),
"p_matrix_s":
len(self.afg.pheromone_selection),
"distance_from_best":
distance_from_best
})
ants = [
Ant(ant_id=i,
alpha=self.alpha,
beta=beta,
metric=self.metric,
use_initials=self.use_initials,
cache_loo=self.cache_loo,
cache_heuristic=self.cache_heuristic,
step=self.step) for i in range(self.ants)
]
beta *= (1 - self.beta_evaporation_rate)
results = []
for ant in ants:
results.append(
ant.run(X=X,
y=y,
graph=self.afg,
random_generator=random,
parallel=self.parallel,
max_errors=self.max_errors))
results = np.array(results)
self.afg.update_pheromone_matrix_evaporation(self.evaporation_rate)
distance_from_best = np.mean(np.abs(results - best_score))
best_ant = np.argmax(results)
if self.update_strategy == "best":
ant = ants[best_ant]
self.afg.intensify(ant.current_features,
self.intensification_factor, 1,
self.use_initials)
else:
for ant_score, ant in zip(results, ants):
self.afg.intensify(ant.current_features,
self.intensification_factor, ant_score,
self.use_initials)
if results[best_ant] >= best_score:
iterations_without_improvement = 0
ant = ants[best_ant]
best_score = results[best_ant]
self.best_features = ant.current_features
else:
iterations_without_improvement += 1
if iterations_without_improvement > self.early_stopping:
break
self.classifier_ = NaiveBayes(encode_data=False, metric=self.metric)
if self.final_selection == "BEST":
pass
else:
#An ant traverses the graph deterministically to obtain the features
final_ant = FinalAnt(ant_id=0,
alpha=self.alpha,
beta=beta,
metric=self.metric,
use_initials=self.use_initials,
cache_loo=self.cache_loo,
cache_heuristic=self.cache_heuristic,
step=self.step)
final_ant.run(X=X,
y=y,
graph=self.afg,
random_generator=random,
parallel=self.parallel)
self.best_features = final_ant.current_features
#Train model with final features
self.classifier_.fit(
np.concatenate(
[feature.transform(X) for feature in self.best_features],
axis=1), y)
if self.save_features:
#Save to features to dict
translate_features(features=self.best_features,
feature_encoder=self.feature_encoder_,
categories=self.categories_,
path=self.path,
filename=self.filename)
return self
class PazzaniWrapperNB(PazzaniWrapper):
''''Optimized version of Pazzani's wrapper for the Naive Bayes classifier.
LOO cross validation
Update, add, delete features
'''
def __init__(self, seed=None, strategy="BSEJ", verbose=0):
super().__init__(seed=seed,
strategy=strategy,
verbose=verbose,
cv=None)
def _generate_neighbors_bsej(self, current_columns, X):
if X.shape[1] > 1:
for column_to_drop in range(X.shape[1]):
new_columns = current_columns.copy()
del new_columns[column_to_drop]
yield new_columns, column_to_drop, None, True # Updated column list, columns to remove, columns to add, delete?
for features in combinations(np.arange(X.shape[1]), 2):
new_col_name = flatten([
current_columns[features[0]], current_columns[features[1]]
])
new_columns = current_columns.copy()
new_columns.append(tuple(new_col_name))
columns_to_drop = sorted(features, reverse=True)
del new_columns[columns_to_drop[0]]
del new_columns[columns_to_drop[1]]
combined_columns = combine_columns(X, list(features))
yield new_columns, list(
columns_to_drop), combined_columns, False
def fit_bsej(self, X, y):
self.evaluate = memoize(_evaluate, attribute_to_cache="columns")
current_best = X.copy()
current_columns = deque(range(X.shape[1]))
best_score = self.evaluate(self.classifier,
current_best,
y,
columns=current_columns,
fit=True)
stop = False
while not stop:
update = False
stop = True
if self.verbose:
print("Current Best: ", current_columns, " Score: ",
best_score)
for new_columns, columns_to_delete, columns_to_add, delete in self._generate_neighbors_bsej(
current_columns, current_best):
if delete:
action = "DELETE"
# Update classifier and get validation result
self.classifier.remove_feature(columns_to_delete)
neighbor = np.delete(current_best,
columns_to_delete,
axis=1)
score = self.evaluate(self.classifier,
neighbor,
y,
columns=new_columns,
fit=False)
# Restore the column for the next iteration
self.classifier.add_features(
current_best[:, columns_to_delete].reshape(-1, 1),
y,
index=[columns_to_delete])
else:
action = "ADD"
self.classifier.add_features(columns_to_add, y)
self.classifier.remove_feature(columns_to_delete[0])
self.classifier.remove_feature(columns_to_delete[1])
neighbor = np.delete(current_best,
columns_to_delete,
axis=1)
neighbor = np.concatenate([neighbor, columns_to_add],
axis=1)
score = self.evaluate(self.classifier,
neighbor,
y,
columns=new_columns,
fit=False)
if self.classifier.n_features_ == 1:
# We reverse it for insert order
self.classifier.add_features(
current_best[:, columns_to_delete], y)
self.classifier.remove_feature(0)
else:
self.classifier.remove_feature(neighbor.shape[1] - 1)
# We reverse it for insert order
self.classifier.add_features(
current_best[:, columns_to_delete],
y,
index=columns_to_delete)
if self.verbose == 2:
print("\tNeighbor: ", new_columns, " Score: ", score)
if score > best_score:
stop = False
best_columns = new_columns
best_action = action
best_score = score
best_columns_to_delete = columns_to_delete
update = True
if best_action == "ADD":
best_columns_to_add = columns_to_add
if score == 1.0:
stop = True
break
if update:
current_columns = best_columns
if best_action == "DELETE":
current_best = np.delete(current_best,
best_columns_to_delete,
axis=1)
# Update best
self.classifier.remove_feature(best_columns_to_delete)
else:
current_best = np.delete(current_best,
best_columns_to_delete,
axis=1)
current_best = np.concatenate(
[current_best, best_columns_to_add], axis=1)
# Update classifier
self.classifier.add_features(best_columns_to_add, y)
self.classifier.remove_feature(best_columns_to_delete[0])
self.classifier.remove_feature(best_columns_to_delete[1])
if self.verbose:
print("Final best: ", list(current_columns), " Score: ",
best_score)
self.features_ = current_columns
self.feature_transformer = lambda X: join_columns(
X, columns=self.features_)
model = self.classifier.fit(self.feature_transformer(X), y)
return self
def _generate_neighbors_fssj(self, current_columns, individual,
original_data, available_columns):
if available_columns:
for index, col in enumerate(available_columns):
new_columns = current_columns.copy()
new_columns.append(col)
new_available_columns = available_columns.copy()
del new_available_columns[index]
column_to_add = original_data[:, col].reshape(-1, 1)
column_to_delete = None
# New columns, Availables,ColumnToDelete,ColumnToAdd,Delete?
yield new_columns, new_available_columns, column_to_delete, column_to_add, False
if individual is not None and individual.shape[
1] > 0 and available_columns:
for features_index in product(np.arange(len(available_columns)),
np.arange(len(current_columns))):
features = available_columns[
features_index[0]], current_columns[features_index[1]]
new_col_name = flatten([features[0], features[1]])
new_available_columns = available_columns.copy()
del new_available_columns[features_index[0]]
new_columns = current_columns.copy()
new_columns.append(tuple(new_col_name))
del new_columns[features_index[1]]
separated_columns = np.concatenate([
original_data[:, features[0]].reshape(-1, 1),
individual[:, features_index[1]].reshape(-1, 1)
],
axis=1)
if isinstance(features[1], tuple):
features = list(features)
features[1] = list(features[1])
features = tuple(features)
column_to_delete = features_index[1]
combined_columns = combine_columns(separated_columns)
column_to_add = combined_columns
yield new_columns, new_available_columns, column_to_delete, column_to_add, True
def fit_fssj(self, X, y):
self.evaluate = memoize(_evaluate, attribute_to_cache="columns")
current_best = None
current_columns = deque()
available_columns = list(range(X.shape[1]))
best_score = -float("inf")
stop = False
while not stop:
update = False
stop = True
# self.classifier.encode_data=True
if self.verbose:
print("Current Best: ", current_columns, " Score: ",
best_score, "Available columns: ", available_columns)
for new_columns, new_available_columns, column_to_delete, column_to_add, delete in self._generate_neighbors_fssj(
current_columns=current_columns,
individual=current_best,
original_data=X,
available_columns=available_columns):
if delete:
action = "JOIN"
# Update classifier and get validation result
self.classifier.add_features(column_to_add, y)
self.classifier.remove_feature(column_to_delete)
neighbor = np.concatenate([current_best, column_to_add],
axis=1)
neighbor = np.delete(neighbor, column_to_delete, axis=1)
score = self.evaluate(self.classifier,
neighbor,
y,
columns=new_columns,
fit=False)
# Restore the column for the next iteration
if neighbor.shape[1] == 1:
self.classifier.fit(current_best, y)
else:
self.classifier.remove_feature(neighbor.shape[1] - 1)
self.classifier.add_features(
current_best[:, column_to_delete].reshape(-1, 1),
y,
index=[column_to_delete])
else:
action = "ADD"
if current_best is None:
neighbor = column_to_add
self.classifier.fit(neighbor, y)
else:
neighbor = np.concatenate(
[current_best, column_to_add], axis=1)
self.classifier.add_features(column_to_add, y)
score = self.evaluate(self.classifier,
neighbor,
y,
columns=new_columns,
fit=False)
if current_best is None:
self.classifier = NaiveBayes(encode_data=True)
else:
self.classifier.remove_feature(neighbor.shape[1] - 1)
if self.verbose == 2:
print("\tNeighbour: ", new_columns, " Score: ", score,
"Available columns: ", new_available_columns)
if score > best_score:
stop = False
best_columns = new_columns
best_available_columns = new_available_columns
best_action = action
best_score = score
best_column_to_delete = column_to_delete
best_column_to_add = column_to_add
update = True
if score == 1.0:
stop = True
break
if update:
current_columns = best_columns
available_columns = best_available_columns
if best_action == "JOIN":
self.classifier.add_features(best_column_to_add, y)
self.classifier.remove_feature(best_column_to_delete)
current_best = np.concatenate(
[current_best, best_column_to_add], axis=1)
current_best = np.delete(current_best,
best_column_to_delete,
axis=1)
else:
if current_best is None:
current_best = best_column_to_add
self.classifier.fit(current_best, y)
else:
current_best = np.concatenate(
[current_best, best_column_to_add], axis=1)
self.classifier.add_features(best_column_to_add, y)
if self.verbose:
print("Final best: ", list(current_columns), " Score: ",
best_score)
self.features_ = current_columns
self.feature_transformer = lambda X: join_columns(
X, columns=self.features_)
model = self.classifier.fit(self.feature_transformer(X), y)
return self
def evaluate(self, classifier, X, y, fit=True, columns=None):
return _evaluate(classifier, X, y, fit=True, columns=None)
def scoring_comparison(base_path,datasets,verbose=1,test_size=0.3,seed=None,n_iterations=30):
column_names = ["dataset",
"custom_training_score",
"custom_test_score",
"categorical_training_score",
"categorical_test_score"]
data =[]
clf_no_encoding = NaiveBayes(encode_data=True)
clf_categorical_sklearn = CategoricalNB()
datasets_iter = tqdm(datasets, bar_format='{l_bar}{bar:20}{r_bar}{bar:-10b}')
c = CustomOrdinalFeatureEncoder()
l = CustomLabelEncoder()
for dataset in datasets_iter:
dataset_name, label = dataset
data_filename = f"{dataset_name}.data.csv"
test_filename = f"{dataset_name}.test.csv"
X, y = get_X_y_from_database(base_path=base_path,
name = dataset_name,
data = data_filename,
test = test_filename,
label = label)
custom_train = []
custom_test = []
sklearn_train = []
sklearn_test = []
X = c.fit_transform(X)
y = l.fit_transform(y)
for iteration in range(n_iterations):
if verbose:
datasets_iter.set_postfix({"Dataset": dataset_name, "seed":iteration})
datasets_iter.refresh()
try:
X_train,X_test,y_train,y_test = train_test_split(X,y,
test_size=test_size,
random_state=seed+iteration,
shuffle=True,
stratify=y)
except:
#Not enough values to stratify y
X_train,X_test,y_train,y_test = train_test_split(X,y,
test_size=test_size,
random_state=seed+iteration,
shuffle=True
)
#Fit
clf_no_encoding.fit(X_train,y_train)
clf_categorical_sklearn.min_categories = [1+np.max(np.concatenate([X_train[:,j],X_test[:,j]])) for j in range(X_train.shape[1])]
clf_categorical_sklearn.fit(X_train,y_train)
#Predict
custom_train.append(clf_no_encoding.score(X_train,y_train))
custom_test.append(clf_no_encoding.score(X_test,y_test))
sklearn_train.append(clf_categorical_sklearn.score(X_train,y_train))
sklearn_test.append(clf_categorical_sklearn.score(X_test,y_test))
data.append([dataset_name,np.mean(custom_train),np.mean(custom_test),np.mean(sklearn_train),np.mean(sklearn_test)])
return pd.DataFrame(data,columns = column_names)
def explore(self, X, y, graph, random_generator, parallel, max_errors=0):
'''
Search method that follows the following steps:
1. The initial node is connected to all the others (roulette wheel selection is performed)
2. There are 2 type of nodes (corresponding to an original feature (2.1) or corresponding to a value of a feature (2.2)):
2.1. If the selected node is an original feature we add it to the selected subset and go to step 3.
2.2. If the selected node is part of a logical feature then we select another node (the CONSTRUCTION step will not return full original features)
3. Compute the score
3.1. If it improves the previous one
3.1.1 Add the feature to the current subset
3.1.2 Update the score
3.1.3 Select another node (SELECTION step)
3.1.4 Go to step 2
3.2. If not, the exploration ends
Note: Threading does not speed up the calculations as they are CPU bound and in python only I/O operations will benefit from this parallelism
GPU improvement would reduce the time of the exploration.
'''
self.step = math.ceil(math.log2(X.shape[1]))
self.current_features = []
selected_nodes = set()
constructed_nodes = set()
classifier = NaiveBayes(encode_data=False, metric=self.metric)
current_score = np.NINF
score = 0
if self.use_initials:
self.current_features = [
DummyFeatureConstructor(j) for j in range(X.shape[1])
]
classifier.fit(X, y)
current_transformed_features_numpy = np.concatenate(
[f.transform(X) for f in self.current_features], axis=1)
score = self.evaluate_loo(self.current_features, classifier,
current_transformed_features_numpy, y)
current_score = score
selected_nodes.update(graph.get_original_ids())
if len(self.current_features) == 0:
current_transformed_features_numpy = None
initial, pheromones, heuristics = graph.get_initial_nodes(
selected_nodes)
probabilities = self.compute_probability(pheromones, heuristics)
index = self.choose_next(probabilities, random_generator)
node_id, selected_node = initial[index]
# SU variable contains the MIFS-SU for the selected variable
current_su = 0
su = heuristics[index]
is_fitted = self.use_initials
feature_constructor = None
n_errors = 0
number_steps = 1
while True:
current_score = score
if selected_node[1] is None:
# Original Feature
feature_constructor = DummyFeatureConstructor(selected_node[0])
selected_nodes.add(node_id)
else:
# Need to construct next feature and compute heuristic value for the feature to replace temporal su from half-var
neighbours, pheromones = graph.get_neighbours(
selected_node, constructed_nodes, step="CONSTRUCTION")
if len(neighbours) == 0:
break
if self.beta != 0:
if parallel:
with concurrent.futures.ThreadPoolExecutor(
) as executor:
futures = []
for neighbour in neighbours:
futures.append(
executor.submit(
self.compute_neighbour_sufs,
neighbour=neighbour,
transformed_features=
current_transformed_features_numpy,
constructors=self.current_features,
selected_node=selected_node,
current_su=current_su,
X=X,
y=y))
concurrent.futures.wait(
futures,
timeout=None,
return_when='ALL_COMPLETED')
su = [future.result() for future in futures]
else:
su = [
self.compute_neighbour_sufs(
neighbour=neighbour,
transformed_features=
current_transformed_features_numpy,
selected_node=selected_node,
constructors=self.current_features,
current_su=current_su,
X=X,
y=y) for neighbour in neighbours
]
else:
#Avoid unnecessary evaluation
su = np.ones(len(neighbours))
probabilities = self.compute_probability(
pheromones, np.array(su))
index = self.choose_next(probabilities, random_generator)
su = su[index]
feature_constructor = create_feature(
neighbours[index][2],
[selected_node, neighbours[index][1]])
constructed_nodes.add(
frozenset(
(node_id, neighbours[index][0], neighbours[index][2])))
node_id, selected_node = neighbours[index][:2]
# Assess new feature
transformed_feature = feature_constructor.transform(X)
if is_fitted:
classifier.add_features(transformed_feature, y)
else:
classifier.fit(transformed_feature, y)
is_fitted = True
if current_transformed_features_numpy is None:
current_transformed_features_numpy = transformed_feature
else:
current_transformed_features_numpy = append_column_to_numpy(
current_transformed_features_numpy, transformed_feature)
if number_steps >= self.step:
score = self.evaluate_loo(
self.current_features + [feature_constructor], classifier,
current_transformed_features_numpy, y)
if score <= current_score:
if n_errors >= max_errors:
break
else:
n_errors += 1
else:
n_errors = 0
number_steps = 0
else:
number_steps += 1
current_su = su
self.current_features.append(feature_constructor)
current_score = score
# Select next
neighbours, pheromones = graph.get_neighbours(selected_node,
selected_nodes,
step="SELECTION")
# Compute heuristic
su = []
if len(neighbours) == 0:
break
if self.beta != 0:
for neighbour, pheromone in zip(neighbours, pheromones):
if neighbour[1][1] is None:
# Original variable
su.append(
self.compute_sufs_cached(
current_su,
current_transformed_features_numpy,
X[:, neighbour[1][0]],
self.current_features,
DummyFeatureConstructor(neighbour[1][0]),
y,
minimum=0))
else:
# This is a temporal variable that will not be finally selected but only used to calculate the heuristic
su.append(
self.compute_sufs_cached(
current_su,
current_transformed_features_numpy,
X[:, neighbour[1][0]] == neighbour[1][1],
self.current_features,
FeatureOperand(feature_index=neighbour[1][0],
value=neighbour[1][1]),
y,
minimum=0))
else:
su = np.ones(len(neighbours))
probabilities = self.compute_probability(pheromones, np.array(su))
index = self.choose_next(probabilities, random_generator)
su = su[index]
node_id, selected_node = neighbours[index][:2]
if current_transformed_features_numpy.shape[1] > len(
self.current_features):
current_transformed_features_numpy = np.delete(
current_transformed_features_numpy, -1, axis=1)
self.final_score = self.evaluate_loo(
self.current_features, classifier,
current_transformed_features_numpy, y)
return self.final_score
