def main(args):
print('initialize BigML API')
if args.username and args.apikey:
api = BigML(args.username,args.apikey)
else:
api = BigML()
print('generate cross validation splits')
cv_files = generate_cross_validation(args.filename,args.nfolds)
cv_datasets = []
params = {'tags':[args.tag]}
if args.objective_field >= 0:
params['objective_field'] = {'id':'%06x' % args.objective_field}
for (train_file,test_file) in cv_files:
if args.sequential:
# wait for source before creating dataset
train_source = api.create_source(train_file,params)
train_dataset = api.create_dataset(train_source,params)
if api.ok(train_dataset):
test_source = api.create_source(test_file,params)
test_dataset = api.create_dataset(test_source,params)
else:
# upload sources in parallel and create datasets in parallel
train_source = api.create_source(train_file,params)
test_source = api.create_source(test_file,params)
train_dataset = api.create_dataset(train_source,params)
test_dataset = api.create_dataset(test_source,params)
cv_datasets.append((train_dataset,test_dataset))
# don't pass objective field to model
del(params['objective_field'])
# wait for dataset creation to finish so we can find out the number of features
dataset_res = api.check_resource(cv_datasets[0][0],api.get_dataset)
dataset_obj = dataset_res['object']
# initial feature set
field_ids = dataset_obj['fields'].keys()
field_ids.remove(dataset_obj['objective_field']['id'])
initial_state = [False for id in field_ids]
# do best-first search
done = False
open_list = [(initial_state,0)]
closed_list = []
best_accuracy = -1
best_unchanged_count = 0
while not done:
(v,fv) = find_max_state(open_list)
v_ids = [field_ids[i] for (i,val) in enumerate(v) if val]
print('Max state is: %s\n Accuracy = %f' % (v_ids,fv))
closed_list.append((v,fv))
open_list.remove((v,fv))
if (fv - EPSILON) > best_accuracy:
best_state = v
best_accuracy = fv
best_unchanged_count = 0
print('new best state')
else:
best_unchanged_count += 1
children = expand_state(v)
for c in children:
if (c not in [pair[0] for pair in open_list]
and c not in [pair[0] for pair in closed_list]):
input_fields = [id for (i,id) in enumerate(field_ids) if c[i]]
print('Evaluating %s' % input_fields)
params['input_fields'] = input_fields
val = evaluate(cv_datasets,params,api,args.penalty,args.sequential)
open_list.append((c,val))
if best_unchanged_count >= args.staleness:
done = True
best_features = [field_ids[i] for (i,val) in enumerate(best_state) if val]
print('The best feature subset is: %s \n Accuracy = %0.2f%%' % (best_features,best_accuracy*100))
print('Evaluated %d/%d feature subsets' % ((len(open_list) + len(closed_list)),2**len(field_ids)))
class Cluster(ModelFields):
""" A lightweight wrapper around a cluster model.
Uses a BigML remote cluster model to build a local version that can be used
to generate centroid predictions locally.
"""
def __init__(self, cluster, api=None):
self.resource_id = None
self.centroids = None
self.cluster_global = None
self.total_ss = None
self.within_ss = None
self.between_ss = None
self.ratio_ss = None
self.critical_value = None
self.default_numeric_value = None
self.k = None
self.summary_fields = []
self.scales = {}
self.term_forms = {}
self.tag_clouds = {}
self.term_analysis = {}
self.item_analysis = {}
self.items = {}
self.datasets = {}
self.api = api
if self.api is None:
self.api = BigML(storage=STORAGE)
self.resource_id, cluster = get_resource_dict( \
cluster, "cluster", api=api)
if 'object' in cluster and isinstance(cluster['object'], dict):
cluster = cluster['object']
if 'clusters' in cluster and isinstance(cluster['clusters'], dict):
status = get_status(cluster)
if 'code' in status and status['code'] == FINISHED:
self.default_numeric_value = cluster.get( \
"default_numeric_value")
self.summary_fields = cluster.get("summary_fields", [])
self.datasets = cluster.get("cluster_datasets", {})
the_clusters = cluster['clusters']
cluster_global = the_clusters.get('global')
clusters = the_clusters['clusters']
self.centroids = [Centroid(centroid) for centroid in clusters]
self.cluster_global = cluster_global
if cluster_global:
self.cluster_global = Centroid(cluster_global)
# "global" has no "name" and "count" then we set them
self.cluster_global.name = GLOBAL_CLUSTER_LABEL
self.cluster_global.count = \
self.cluster_global.distance['population']
self.total_ss = the_clusters.get('total_ss')
self.within_ss = the_clusters.get('within_ss')
if not self.within_ss:
self.within_ss = sum(centroid.distance['sum_squares']
for centroid in self.centroids)
self.between_ss = the_clusters.get('between_ss')
self.ratio_ss = the_clusters.get('ratio_ss')
self.critical_value = cluster.get('critical_value', None)
self.k = cluster.get('k')
self.scales.update(cluster['scales'])
self.term_forms = {}
self.tag_clouds = {}
self.term_analysis = {}
fields = cluster['clusters']['fields']
summary_fields = cluster['summary_fields']
for field_id in summary_fields:
try:
del fields[field_id]
except KeyError:
# clusters retrieved from API will only contain
# model fields
pass
for field_id, field in fields.items():
if field['optype'] == 'text':
self.term_forms[field_id] = {}
self.term_forms[field_id].update(
field['summary']['term_forms'])
self.tag_clouds[field_id] = {}
self.tag_clouds[field_id].update(
field['summary']['tag_cloud'])
self.term_analysis[field_id] = {}
self.term_analysis[field_id].update(
field['term_analysis'])
if field['optype'] == 'items':
self.items[field_id] = {}
self.items[field_id].update(
dict(field['summary']['items']))
self.item_analysis[field_id] = {}
self.item_analysis[field_id].update(
field['item_analysis'])
ModelFields.__init__(self, fields)
if not all(
[field_id in self.fields for field_id in self.scales]):
raise Exception("Some fields are missing"
" to generate a local cluster."
" Please, provide a cluster with"
" the complete list of fields.")
else:
raise Exception("The cluster isn't finished yet")
else:
raise Exception("Cannot create the Cluster instance. Could not"
" find the 'clusters' key in the resource:\n\n%s" %
cluster)
def centroid(self, input_data):
"""Returns the id of the nearest centroid
"""
clean_input_data, unique_terms = self._prepare_for_distance( \
input_data)
nearest = {
'centroid_id': None,
'centroid_name': None,
'distance': float('inf')
}
for centroid in self.centroids:
distance2 = centroid.distance2(clean_input_data,
unique_terms,
self.scales,
stop_distance2=nearest['distance'])
if distance2 is not None:
nearest = {
'centroid_id': centroid.centroid_id,
'centroid_name': centroid.name,
'distance': distance2
}
nearest['distance'] = math.sqrt(nearest['distance'])
return nearest
@property
def is_g_means(self):
"""Checks whether the cluster has been created using g-means
"""
return self.critical_value is not None
def fill_numeric_defaults(self, input_data, average="mean"):
"""Checks whether input data is missing a numeric field and
fills it with the average quantity provided in the
``average`` parameter
"""
for field_id, field in self.fields.items():
if (field_id not in self.summary_fields and \
field['optype'] == NUMERIC and
field_id not in input_data):
if average not in NUMERIC_DEFAULTS:
raise ValueError("The available defaults are: %s" % \
", ".join(NUMERIC_DEFAULTS))
default_value = 0 if average == "zero" \
else field['summary'].get(average)
input_data[field_id] = default_value
return input_data
def get_unique_terms(self, input_data):
"""Parses the input data to find the list of unique terms in the
tag cloud
"""
unique_terms = {}
for field_id in self.term_forms:
if field_id in input_data:
input_data_field = input_data.get(field_id, '')
if isinstance(input_data_field, basestring):
case_sensitive = self.term_analysis[field_id].get(
'case_sensitive', True)
token_mode = self.term_analysis[field_id].get(
'token_mode', 'all')
if token_mode != TM_FULL_TERM:
terms = parse_terms(input_data_field,
case_sensitive=case_sensitive)
else:
terms = []
if token_mode != TM_TOKENS:
terms.append(input_data_field if case_sensitive else
input_data_field.lower())
unique_terms[field_id] = get_unique_terms(
terms, self.term_forms[field_id],
self.tag_clouds.get(field_id, []))
else:
unique_terms[field_id] = input_data_field
del input_data[field_id]
# the same for items fields
for field_id in self.item_analysis:
if field_id in input_data:
input_data_field = input_data.get(field_id, '')
if isinstance(input_data_field, basestring):
# parsing the items in input_data
separator = self.item_analysis[field_id].get(
'separator', ' ')
regexp = self.item_analysis[field_id].get(
'separator_regexp')
if regexp is None:
regexp = ur'%s' % re.escape(separator)
terms = parse_items(input_data_field, regexp)
unique_terms[field_id] = get_unique_terms(
terms, {}, self.items.get(field_id, []))
else:
unique_terms[field_id] = input_data_field
del input_data[field_id]
return unique_terms
def centroids_distance(self, to_centroid):
"""Statistic distance information from the given centroid
to the rest of centroids in the cluster
"""
intercentroid_distance = []
unique_terms = self.get_unique_terms(to_centroid.center)
distances = []
for centroid in self.centroids:
if centroid.centroid_id != to_centroid.centroid_id:
distances.append(
math.sqrt(
centroid.distance2(to_centroid.center, unique_terms,
self.scales)))
for measure, function in INTERCENTROID_MEASURES:
result = function(distances)
intercentroid_distance.append([measure, result])
return intercentroid_distance
def cluster_global_distance(self):
"""Used to populate the intercentroid distances columns in the CSV
report. For now we don't want to compute real distance and jsut
display "N/A"
"""
intercentroid_distance = []
for measure, _ in INTERCENTROID_MEASURES:
intercentroid_distance.append([measure, 'N/A'])
return intercentroid_distance
def _prepare_for_distance(self, input_data):
"""Prepares the fields to be able to compute the distance2
"""
# Checks and cleans input_data leaving the fields used in the model
clean_input_data = self.filter_input_data(input_data)
# Checks that all numeric fields are present in input data and
# fills them with the default average (if given) when otherwise
try:
self.fill_numeric_defaults(clean_input_data,
self.default_numeric_value)
except ValueError:
raise Exception("Missing values in input data. Input"
" data must contain values for all "
"numeric fields to compute a distance.")
# Strips affixes for numeric values and casts to the final field type
cast(clean_input_data, self.fields)
unique_terms = self.get_unique_terms(clean_input_data)
return clean_input_data, unique_terms
def distances2_to_point(self, reference_point, list_of_points):
"""Computes the cluster square of the distance to an arbitrary
reference point for a list of points.
reference_point: (dict) The field values for the point used as
reference
list_of_points: (dict|Centroid) The field values or a Centroid object
which contains these values
"""
# Checks and cleans input_data leaving the fields used in the model
reference_point, _ = self._prepare_for_distance( \
reference_point)
# mimic centroid structure to use it in distance computation
point_info = {"center": reference_point}
reference = Centroid(point_info)
distances = []
for point in list_of_points:
centroid_id = None
if isinstance(point, Centroid):
centroid_id = point.centroid_id
point = point.center
clean_point, unique_terms = self._prepare_for_distance( \
point)
if clean_point != reference_point:
result = {"data": point, "distance": reference.distance2( \
clean_point, unique_terms, self.scales)}
if centroid_id is not None:
result.update({"centroid_id": centroid_id})
distances.append(result)
return distances
def points_in_cluster(self, centroid_id):
"""Returns the list of data points that fall in one cluster.
"""
cluster_datasets = self.datasets
centroid_dataset = cluster_datasets.get(centroid_id)
if centroid_dataset in [None, ""]:
centroid_dataset = self.api.create_dataset( \
self.resource_id, {"centroid": centroid_id})
self.api.ok(centroid_dataset)
else:
centroid_dataset = self.api.check_resource( \
"dataset/%s" % centroid_dataset)
# download dataset to compute local predictions
downloaded_data = self.api.download_dataset( \
centroid_dataset["resource"])
if PY3:
text_reader = codecs.getreader("utf-8")
downloaded_data = text_reader(downloaded_data)
reader = csv.DictReader(downloaded_data)
points = []
for row in reader:
points.append(row)
return points
def closest_in_cluster(self,
reference_point,
number_of_points=None,
centroid_id=None):
"""Computes the list of data points closer to a reference point.
If no centroid_id information is provided, the points are chosen
from the same cluster as the reference point.
The points are returned in a list, sorted according
to their distance to the reference point. The number_of_points
parameter can be set to truncate the list to a maximum number of
results. The response is a dictionary that contains the
centroid id of the cluster plus the list of points
"""
if centroid_id is not None and centroid_id not in \
[centroid.centroid_id for centroid in self.centroids]:
raise AttributeError( \
"Failed to find the provided centroid_id: %s" % centroid_id)
if centroid_id is None:
# finding the reference point cluster's centroid
centroid_info = self.centroid(reference_point)
centroid_id = centroid_info["centroid_id"]
# reading the points that fall in the same cluster
points = self.points_in_cluster(centroid_id)
# computing distance to reference point
points = self.distances2_to_point(reference_point, points)
points = sorted(points, key=lambda x: x["distance"])
if number_of_points is not None:
points = points[:number_of_points]
for point in points:
point["distance"] = math.sqrt(point["distance"])
return {
"centroid_id": centroid_id,
"reference": reference_point,
"closest": points
}
def sorted_centroids(self, reference_point):
""" Gives the list of centroids sorted according to its distance to
an arbitrary reference point.
"""
close_centroids = self.distances2_to_point( \
reference_point, self.centroids)
for centroid in close_centroids:
centroid["distance"] = math.sqrt(centroid["distance"])
centroid["center"] = centroid["data"]
del centroid["data"]
return {
"reference": reference_point,
"centroids": sorted(close_centroids, key=lambda x: x["distance"])
}
def centroid_features(self, centroid, field_ids, encode=True):
"""Returns features defining the centroid according to the list
of common field ids that define the centroids.
"""
features = []
for field_id in field_ids:
value = centroid.center[field_id]
if isinstance(value, basestring) and encode:
value = value.encode('utf-8')
features.append(value)
return features
def get_data_distribution(self):
"""Returns training data distribution
"""
distribution = [[centroid.name, centroid.count]
for centroid in self.centroids]
return sorted(distribution, key=lambda x: x[0])
def print_global_distribution(self, out=sys.stdout):
"""Prints the line Global: 100% (<total> instances)
"""
output = u""
if self.cluster_global:
output += (u" %s: 100%% (%d instances)\n" %
(self.cluster_global.name, self.cluster_global.count))
out.write(output)
out.flush()
def print_ss_metrics(self, out=sys.stdout):
"""Prints the block of *_ss metrics from the cluster
"""
ss_metrics = [("total_ss (Total sum of squares)", self.total_ss),
("within_ss (Total within-cluster sum of the sum "
"of squares)", self.within_ss),
("between_ss (Between sum of squares)", self.between_ss),
("ratio_ss (Ratio of sum of squares)", self.ratio_ss)]
output = u""
for metric in ss_metrics:
if metric[1]:
output += (u"%s%s: %5f\n" % (INDENT, metric[0], metric[1]))
out.write(output)
out.flush()
def statistics_csv(self, file_name=None):
"""Clusters statistic information in CSV format
"""
rows = []
writer = None
field_ids = self.centroids[0].center.keys()
headers = [u"Centroid_name"]
headers.extend(
[u"%s" % self.fields[field_id]["name"] for field_id in field_ids])
headers.extend([u"Instances"])
intercentroids = False
header_complete = False
centroids_list = sorted(self.centroids, key=lambda x: x.name)
for centroid in centroids_list:
row = [centroid.name]
row.extend(
self.centroid_features(centroid, field_ids, encode=False))
row.append(centroid.count)
if len(self.centroids) > 1:
for measure, result in self.centroids_distance(centroid):
if not intercentroids:
headers.append(u"%s intercentroid distance" % \
measure.title())
row.append(result)
intercentroids = True
for measure, result in centroid.distance.items():
if measure in CSV_STATISTICS:
if not header_complete:
headers.append(u"Distance %s" %
measure.lower().replace("_", " "))
row.append(result)
if not header_complete:
rows.append(headers)
header_complete = True
rows.append(row)
if self.cluster_global:
row = [u"%s" % self.cluster_global.name]
row.extend(
self.centroid_features(self.cluster_global,
field_ids,
encode=False))
row.append(self.cluster_global.count)
if len(self.centroids) > 1:
for measure, result in self.cluster_global_distance():
row.append(result)
for measure, result in self.cluster_global.distance.items():
if measure in CSV_STATISTICS:
row.append(result)
# header is already in rows then insert cluster_global after it
rows.insert(1, row)
if file_name is None:
return rows
with UnicodeWriter(file_name) as writer:
writer.writerows(rows)
def summarize(self, out=sys.stdout):
"""Prints a summary of the cluster info
"""
report_header = ''
if self.is_g_means:
report_header = \
u'G-means Cluster (critical_value=%d)' % self.critical_value
else:
report_header = u'K-means Cluster (k=%d)' % self.k
out.write(report_header +
' with %d centroids\n\n' % len(self.centroids))
out.write(u"Data distribution:\n")
# "Global" is set as first entry
self.print_global_distribution(out=out)
print_distribution(self.get_data_distribution(), out=out)
out.write(u"\n")
centroids_list = [self.cluster_global] if self.cluster_global else []
centroids_list.extend(sorted(self.centroids, key=lambda x: x.name))
out.write(u"Cluster metrics:\n")
self.print_ss_metrics(out=out)
out.write(u"\n")
out.write(u"Centroids:\n")
for centroid in centroids_list:
out.write(utf8(u"\n%s%s: " % (INDENT, centroid.name)))
connector = ""
for field_id, value in centroid.center.items():
if isinstance(value, basestring):
value = u"\"%s\"" % value
out.write(
utf8(u"%s%s: %s" %
(connector, self.fields[field_id]['name'], value)))
connector = ", "
out.write(u"\n\n")
out.write(u"Distance distribution:\n\n")
for centroid in centroids_list:
centroid.print_statistics(out=out)
out.write(u"\n")
if len(self.centroids) > 1:
out.write(u"Intercentroid distance:\n\n")
centroids_list = (centroids_list[1:]
if self.cluster_global else centroids_list)
for centroid in centroids_list:
out.write(
utf8(u"%sTo centroid: %s\n" % (INDENT, centroid.name)))
for measure, result in self.centroids_distance(centroid):
out.write(u"%s%s: %s\n" % (INDENT * 2, measure, result))
out.write(u"\n")
class Cluster(ModelFields):
""" A lightweight wrapper around a cluster model.
Uses a BigML remote cluster model to build a local version that can be used
to generate centroid predictions locally.
"""
def __init__(self, cluster, api=None):
self.resource_id = None
self.centroids = None
self.cluster_global = None
self.total_ss = None
self.within_ss = None
self.between_ss = None
self.ratio_ss = None
self.critical_value = None
self.default_numeric_value = None
self.k = None
self.summary_fields = []
self.scales = {}
self.term_forms = {}
self.tag_clouds = {}
self.term_analysis = {}
self.item_analysis = {}
self.items = {}
self.datasets = {}
self.api = api
# checks whether the information needed for local predictions is in
# the first argument
if isinstance(cluster, dict) and \
not check_model_fields(cluster):
# if the fields used by the cluster are not
# available, use only ID to retrieve it again
cluster = get_cluster_id(cluster)
self.resource_id = cluster
if not (isinstance(cluster, dict) and 'resource' in cluster and
cluster['resource'] is not None):
if api is None:
api = BigML(storage=STORAGE)
self.api = api
self.resource_id = get_cluster_id(cluster)
if self.resource_id is None:
raise Exception(api.error_message(cluster,
resource_type='cluster',
method='get'))
query_string = ONLY_MODEL
cluster = retrieve_resource(api, self.resource_id,
query_string=query_string)
else:
self.resource_id = get_cluster_id(cluster)
if 'object' in cluster and isinstance(cluster['object'], dict):
cluster = cluster['object']
if 'clusters' in cluster and isinstance(cluster['clusters'], dict):
status = get_status(cluster)
if 'code' in status and status['code'] == FINISHED:
self.default_numeric_value = cluster.get( \
"default_numeric_value")
self.summary_fields = cluster.get("summary_fields", [])
self.datasets = cluster.get("cluster_datasets", {})
the_clusters = cluster['clusters']
cluster_global = the_clusters.get('global')
clusters = the_clusters['clusters']
self.centroids = [Centroid(centroid) for centroid in clusters]
self.cluster_global = cluster_global
if cluster_global:
self.cluster_global = Centroid(cluster_global)
# "global" has no "name" and "count" then we set them
self.cluster_global.name = GLOBAL_CLUSTER_LABEL
self.cluster_global.count = \
self.cluster_global.distance['population']
self.total_ss = the_clusters.get('total_ss')
self.within_ss = the_clusters.get('within_ss')
if not self.within_ss:
self.within_ss = sum(centroid.distance['sum_squares'] for
centroid in self.centroids)
self.between_ss = the_clusters.get('between_ss')
self.ratio_ss = the_clusters.get('ratio_ss')
self.critical_value = cluster.get('critical_value', None)
self.k = cluster.get('k')
self.scales.update(cluster['scales'])
self.term_forms = {}
self.tag_clouds = {}
self.term_analysis = {}
fields = cluster['clusters']['fields']
summary_fields = cluster['summary_fields']
for field_id in summary_fields:
del fields[field_id]
for field_id, field in fields.items():
if field['optype'] == 'text':
self.term_forms[field_id] = {}
self.term_forms[field_id].update(field[
'summary']['term_forms'])
self.tag_clouds[field_id] = {}
self.tag_clouds[field_id].update(field[
'summary']['tag_cloud'])
self.term_analysis[field_id] = {}
self.term_analysis[field_id].update(
field['term_analysis'])
if field['optype'] == 'items':
self.items[field_id] = {}
self.items[field_id].update(
dict(field['summary']['items']))
self.item_analysis[field_id] = {}
self.item_analysis[field_id].update(
field['item_analysis'])
ModelFields.__init__(self, fields)
if not all([field_id in self.fields for
field_id in self.scales]):
raise Exception("Some fields are missing"
" to generate a local cluster."
" Please, provide a cluster with"
" the complete list of fields.")
else:
raise Exception("The cluster isn't finished yet")
else:
raise Exception("Cannot create the Cluster instance. Could not"
" find the 'clusters' key in the resource:\n\n%s" %
cluster)
def centroid(self, input_data, by_name=True):
"""Returns the id of the nearest centroid
"""
clean_input_data, unique_terms = self._prepare_for_distance( \
input_data, by_name=by_name)
nearest = {'centroid_id': None, 'centroid_name': None,
'distance': float('inf')}
for centroid in self.centroids:
distance2 = centroid.distance2(clean_input_data, unique_terms,
self.scales,
stop_distance2=nearest['distance'])
if distance2 is not None:
nearest = {'centroid_id': centroid.centroid_id,
'centroid_name': centroid.name,
'distance': distance2}
nearest['distance'] = math.sqrt(nearest['distance'])
return nearest
@property
def is_g_means(self):
"""Checks whether the cluster has been created using g-means
"""
return self.critical_value is not None
def fill_numeric_defaults(self, input_data, average="mean"):
"""Checks whether input data is missing a numeric field and
fills it with the average quantity provided in the
``average`` parameter
"""
for field_id, field in self.fields.items():
if (field_id not in self.summary_fields and \
field['optype'] not in OPTIONAL_FIELDS and
field_id not in input_data):
if average not in NUMERIC_DEFAULTS:
raise ValueError("The available defaults are: %s" % \
", ".join(NUMERIC_DEFAULTS))
default_value = 0 if average == "zero" \
else field['summary'].get(average)
input_data[field_id] = default_value
return input_data
def get_unique_terms(self, input_data):
"""Parses the input data to find the list of unique terms in the
tag cloud
"""
unique_terms = {}
for field_id in self.term_forms:
if field_id in input_data:
input_data_field = input_data.get(field_id, '')
if isinstance(input_data_field, basestring):
case_sensitive = self.term_analysis[field_id].get(
'case_sensitive', True)
token_mode = self.term_analysis[field_id].get(
'token_mode', 'all')
if token_mode != TM_FULL_TERM:
terms = parse_terms(input_data_field,
case_sensitive=case_sensitive)
else:
terms = []
if token_mode != TM_TOKENS:
terms.append(
input_data_field if case_sensitive
else input_data_field.lower())
unique_terms[field_id] = get_unique_terms(
terms, self.term_forms[field_id],
self.tag_clouds.get(field_id, []))
else:
unique_terms[field_id] = input_data_field
del input_data[field_id]
# the same for items fields
for field_id in self.item_analysis:
if field_id in input_data:
input_data_field = input_data.get(field_id, '')
if isinstance(input_data_field, basestring):
# parsing the items in input_data
separator = self.item_analysis[field_id].get(
'separator', ' ')
regexp = self.item_analysis[field_id].get(
'separator_regexp')
if regexp is None:
regexp = ur'%s' % re.escape(separator)
terms = parse_items(input_data_field, regexp)
unique_terms[field_id] = get_unique_terms(
terms, {},
self.items.get(field_id, []))
else:
unique_terms[field_id] = input_data_field
del input_data[field_id]
return unique_terms
def centroids_distance(self, to_centroid):
"""Statistic distance information from the given centroid
to the rest of centroids in the cluster
"""
intercentroid_distance = []
unique_terms = self.get_unique_terms(to_centroid.center)
distances = []
for centroid in self.centroids:
if centroid.centroid_id != to_centroid.centroid_id:
distances.append(
math.sqrt(
centroid.distance2(to_centroid.center,
unique_terms,
self.scales)))
for measure, function in INTERCENTROID_MEASURES:
result = function(distances)
intercentroid_distance.append([measure, result])
return intercentroid_distance
def cluster_global_distance(self):
"""Used to populate the intercentroid distances columns in the CSV
report. For now we don't want to compute real distance and jsut
display "N/A"
"""
intercentroid_distance = []
for measure, _ in INTERCENTROID_MEASURES:
intercentroid_distance.append([measure, 'N/A'])
return intercentroid_distance
def _prepare_for_distance(self, input_data, by_name=True):
"""Prepares the fields to be able to compute the distance2
"""
# Checks and cleans input_data leaving the fields used in the model
clean_input_data = self.filter_input_data(input_data, by_name=by_name)
# Checks that all numeric fields are present in input data and
# fills them with the default average (if given) when otherwise
try:
self.fill_numeric_defaults(clean_input_data,
self.default_numeric_value)
except ValueError:
raise Exception("Missing values in input data. Input"
" data must contain values for all "
"numeric fields to compute a distance.")
# Strips affixes for numeric values and casts to the final field type
cast(clean_input_data, self.fields)
unique_terms = self.get_unique_terms(clean_input_data)
return clean_input_data, unique_terms
def distances2_to_point(self, reference_point,
list_of_points, by_name=True):
"""Computes the cluster square of the distance to an arbitrary
reference point for a list of points.
reference_point: (dict) The field values for the point used as
reference
list_of_points: (dict|Centroid) The field values or a Centroid object
which contains these values
by_name: (boolean) Set if the dict information is keyed by field name.
Expects IDs as keys otherwise.
"""
# Checks and cleans input_data leaving the fields used in the model
reference_point, _ = self._prepare_for_distance( \
reference_point, by_name=by_name)
# mimic centroid structure to use it in distance computation
point_info = {"center": reference_point}
reference = Centroid(point_info)
distances = []
for point in list_of_points:
centroid_id = None
if isinstance(point, Centroid):
centroid_id = point.centroid_id
point = point.center
by_name = False
clean_point, unique_terms = self._prepare_for_distance( \
point, by_name=by_name)
if clean_point != reference_point:
result = {"data": point, "distance": reference.distance2( \
clean_point, unique_terms, self.scales)}
if centroid_id is not None:
result.update({"centroid_id": centroid_id})
distances.append(result)
return distances
def points_in_cluster(self, centroid_id):
"""Returns the list of data points that fall in one cluster.
"""
cluster_datasets = self.datasets
centroid_dataset = cluster_datasets.get(centroid_id)
if self.api is None:
self.api = BigML(storage=STORAGE)
if centroid_dataset in [None, ""]:
centroid_dataset = self.api.create_dataset( \
self.resource_id, {"centroid": centroid_id})
self.api.ok(centroid_dataset)
else:
centroid_dataset = self.api.check_resource( \
"dataset/%s" % centroid_dataset)
# download dataset to compute local predictions
downloaded_data = self.api.download_dataset( \
centroid_dataset["resource"])
if PY3:
text_reader = codecs.getreader("utf-8")
downloaded_data = text_reader(downloaded_data)
reader = csv.DictReader(downloaded_data)
points = []
for row in reader:
points.append(row)
return points
def closest_in_cluster(self, reference_point,
number_of_points=None,
centroid_id=None,
by_name=True):
"""Computes the list of data points closer to a reference point.
If no centroid_id information is provided, the points are chosen
from the same cluster as the reference point.
The points are returned in a list, sorted according
to their distance to the reference point. The number_of_points
parameter can be set to truncate the list to a maximum number of
results. The response is a dictionary that contains the
centroid id of the cluster plus the list of points
"""
if centroid_id is not None and centroid_id not in \
[centroid.centroid_id for centroid in self.centroids]:
raise AttributeError( \
"Failed to find the provided centroid_id: %s" % centroid_id)
if centroid_id is None:
# finding the reference point cluster's centroid
centroid_info = self.centroid(reference_point, by_name=True)
centroid_id = centroid_info["centroid_id"]
# reading the points that fall in the same cluster
points = self.points_in_cluster(centroid_id)
# computing distance to reference point
points = self.distances2_to_point(reference_point, points)
points = sorted(points, key=lambda x: x["distance"])
if number_of_points is not None:
points = points[:number_of_points]
for point in points:
point["distance"] = math.sqrt(point["distance"])
return {"centroid_id": centroid_id, "reference": reference_point,
"closest": points}
def sorted_centroids(self, reference_point, by_name=True):
""" Gives the list of centroids sorted according to its distance to
an arbitrary reference point.
"""
close_centroids = self.distances2_to_point( \
reference_point, self.centroids, by_name=by_name)
for centroid in close_centroids:
centroid["distance"] = math.sqrt(centroid["distance"])
centroid["center"] = centroid["data"]
del centroid["data"]
return {"reference": reference_point,
"centroids": sorted(close_centroids,
key=lambda x: x["distance"])}
def centroid_features(self, centroid, field_ids):
"""Returns features defining the centroid according to the list
of common field ids that define the centroids.
"""
features = []
for field_id in field_ids:
value = centroid.center[field_id]
if isinstance(value, basestring):
value = value.encode('utf-8')
features.append(value)
return features
def get_data_distribution(self):
"""Returns training data distribution
"""
distribution = [[centroid.name, centroid.count] for centroid in
self.centroids]
return sorted(distribution, key=lambda x: x[0])
def print_global_distribution(self, out=sys.stdout):
"""Prints the line Global: 100% (<total> instances)
"""
output = u""
if self.cluster_global:
output += (u" %s: 100%% (%d instances)\n" % (
self.cluster_global.name,
self.cluster_global.count))
out.write(output)
out.flush()
def print_ss_metrics(self, out=sys.stdout):
"""Prints the block of *_ss metrics from the cluster
"""
ss_metrics = [("total_ss (Total sum of squares)", self.total_ss),
("within_ss (Total within-cluster sum of the sum "
"of squares)", self.within_ss),
("between_ss (Between sum of squares)", self.between_ss),
("ratio_ss (Ratio of sum of squares)", self.ratio_ss)]
output = u""
for metric in ss_metrics:
if metric[1]:
output += (u"%s%s: %5f\n" % (INDENT, metric[0], metric[1]))
out.write(output)
out.flush()
def statistics_csv(self, file_name=None):
"""Clusters statistic information in CSV format
"""
rows = []
writer = None
field_ids = self.centroids[0].center.keys()
headers = [u"Centroid_name"]
headers.extend([u"%s" % self.fields[field_id]["name"]
for field_id in field_ids])
headers.extend([u"Instances"])
intercentroids = False
header_complete = False
centroids_list = sorted(self.centroids, key=lambda x: x.name)
for centroid in centroids_list:
row = [centroid.name]
row.extend(self.centroid_features(centroid, field_ids))
row.append(centroid.count)
if len(self.centroids) > 1:
for measure, result in self.centroids_distance(centroid):
if not intercentroids:
headers.append(u"%s intercentroid distance" % \
measure.title())
row.append(result)
intercentroids = True
for measure, result in centroid.distance.items():
if measure in CSV_STATISTICS:
if not header_complete:
headers.append(u"Distance %s" %
measure.lower().replace("_", " "))
row.append(result)
if not header_complete:
rows.append(headers)
header_complete = True
rows.append(row)
if self.cluster_global:
row = [u"%s" % self.cluster_global.name]
row.extend(self.centroid_features(self.cluster_global, field_ids))
row.append(self.cluster_global.count)
if len(self.centroids) > 1:
for measure, result in self.cluster_global_distance():
row.append(result)
for measure, result in self.cluster_global.distance.items():
if measure in CSV_STATISTICS:
row.append(result)
# header is already in rows then insert cluster_global after it
rows.insert(1, row)
if file_name is None:
return rows
with UnicodeWriter(file_name) as writer:
for row in rows:
writer.writerow([item if not isinstance(item, basestring)
else item.encode("utf-8") for item in row])
def summarize(self, out=sys.stdout):
"""Prints a summary of the cluster info
"""
report_header = ''
if self.is_g_means:
report_header = \
u'G-means Cluster (critical_value=%d)' % self.critical_value
else:
report_header = u'K-means Cluster (k=%d)' % self.k
out.write(report_header + ' with %d centroids\n\n' %
len(self.centroids))
out.write(u"Data distribution:\n")
# "Global" is set as first entry
self.print_global_distribution(out=out)
print_distribution(self.get_data_distribution(), out=out)
out.write(u"\n")
centroids_list = [self.cluster_global] if self.cluster_global else []
centroids_list.extend(sorted(self.centroids, key=lambda x: x.name))
out.write(u"Cluster metrics:\n")
self.print_ss_metrics(out=out)
out.write(u"\n")
out.write(u"Centroids:\n")
for centroid in centroids_list:
out.write(utf8(u"\n%s%s: " % (INDENT, centroid.name)))
connector = ""
for field_id, value in centroid.center.items():
if isinstance(value, basestring):
value = u"\"%s\"" % value
out.write(utf8(u"%s%s: %s" % (connector,
self.fields[field_id]['name'],
value)))
connector = ", "
out.write(u"\n\n")
out.write(u"Distance distribution:\n\n")
for centroid in centroids_list:
centroid.print_statistics(out=out)
out.write(u"\n")
if len(self.centroids) > 1:
out.write(u"Intercentroid distance:\n\n")
centroids_list = (centroids_list[1:] if self.cluster_global else
centroids_list)
for centroid in centroids_list:
out.write(utf8(u"%sTo centroid: %s\n" % (INDENT,
centroid.name)))
for measure, result in self.centroids_distance(centroid):
out.write(u"%s%s: %s\n" % (INDENT * 2, measure, result))
out.write(u"\n")
