def get_objective_value(X_data, op_centroids, indicator_vector):
logger.info("Compute objective")
if paraman["--minibatch"]:
final_objective_value = compute_objective_by_batch(X_data, op_centroids, indicator_vector, paraman["--minibatch"])
else:
final_objective_value = compute_objective(X_data, op_centroids, indicator_vector)
resprinter.add({
"final_objective_value": final_objective_value,
})
return final_objective_value
def qmeans(X_data: np.ndarray,
K_nb_cluster: int,
nb_iter: int,
nb_factors: int,
params_palm4msa: dict,
initialization: np.ndarray,
hierarchical_inside=False,
delta_objective_error_threshold=1e-6,
hierarchical_init=False):
"""
:param X_data: The data matrix of n examples in dimensions d in shape (n, d).
:param K_nb_cluster: The number of clusters to look for.
:param nb_iter: The maximum number of iteration.
:param nb_factors: The number of factors for the decomposition.
:param initialization: The initial matrix of centroids not yet factorized.
:param params_palm4msa: The dictionnary of parameters for the palm4msa algorithm.
:param hierarchical_inside: Tell the algorithm if the hierarchical version of palm4msa should be used.
:param delta_objective_error_threshold:
:param hierarchical_init: Tells if the algorithm should make the initialization of sparse factors with the hierarchical version of palm or not.
:return:
"""
assert K_nb_cluster == initialization.shape[0], "The number of cluster {} is not equal to the number of centroids in the initialization {}.".format(K_nb_cluster, initialization.shape[0])
X_data_norms = get_squared_froebenius_norm_line_wise(X_data)
nb_examples = X_data.shape[0]
logger.info("Initializing Qmeans")
init_lambda = params_palm4msa["init_lambda"]
nb_iter_palm = params_palm4msa["nb_iter"]
lst_proj_op_by_fac_step = params_palm4msa["lst_constraint_sets"]
residual_on_right = params_palm4msa["residual_on_right"]
delta_objective_error_threshold_inner_palm = params_palm4msa["delta_objective_error_threshold"]
track_objective_palm = params_palm4msa["track_objective"]
X_centroids_hat = copy.deepcopy(initialization)
lst_factors = init_lst_factors(K_nb_cluster, X_centroids_hat.shape[1], nb_factors)
eye_norm = np.sqrt(K_nb_cluster)
if hierarchical_inside or hierarchical_init:
_lambda_tmp, op_factors, U_centroids, objective_palm, array_objective_hierarchical= \
hierarchical_palm4msa(
arr_X_target=np.eye(K_nb_cluster) @ X_centroids_hat,
lst_S_init=lst_factors,
lst_dct_projection_function=lst_proj_op_by_fac_step,
f_lambda_init=init_lambda * eye_norm,
nb_iter=nb_iter_palm,
update_right_to_left=True,
residual_on_right=residual_on_right,
track_objective_palm=track_objective_palm,
delta_objective_error_threshold_palm=delta_objective_error_threshold_inner_palm,
return_objective_function=track_objective_palm)
else:
_lambda_tmp, op_factors, U_centroids, objective_palm, nb_iter_palm = \
palm4msa(
arr_X_target=np.eye(K_nb_cluster) @ X_centroids_hat,
lst_S_init=lst_factors,
nb_factors=len(lst_factors),
lst_projection_functions=lst_proj_op_by_fac_step[-1][
"finetune"],
f_lambda_init=init_lambda * eye_norm,
nb_iter=nb_iter_palm,
update_right_to_left=True,
track_objective=track_objective_palm,
delta_objective_error_threshold=delta_objective_error_threshold_inner_palm)
lst_factors = None # safe assignment for debug
_lambda = _lambda_tmp / eye_norm
objective_function = np.ones(nb_iter) * -1
lst_all_objective_functions_palm = []
lst_all_objective_functions_palm.append(objective_palm)
i_iter = 0
delta_objective_error = np.inf
while ((i_iter < nb_iter) and (delta_objective_error > delta_objective_error_threshold)):
logger.info("Iteration Qmeans {}".format(i_iter))
lst_factors_ = op_factors.get_list_of_factors()
op_centroids = SparseFactors([lst_factors_[1] * _lambda] + lst_factors_[2:])
###########################
# Cluster assignment step #
###########################
indicator_vector, distances = assign_points_to_clusters(X_data, op_centroids, X_norms=X_data_norms)
#######################
# Cluster update step #
#######################
# get the number of observation in each cluster
cluster_names, counts = np.unique(indicator_vector, return_counts=True)
cluster_names_sorted = np.argsort(cluster_names)
# Update centroid location using the newly (it happens in the assess_cluster_integrity function)
# assigned data point classes
# and check if all clusters still have points
# and change the object X_centroids_hat in place if some cluster have lost points (biggest cluster)
counts, cluster_names_sorted = update_clusters_with_integrity_check(X_data,
X_data_norms,
X_centroids_hat, # in place changes
K_nb_cluster,
counts,
indicator_vector,
distances,
cluster_names,
cluster_names_sorted)
#################
# PALM4MSA step #
#################
# create the diagonal of the sqrt of those counts
diag_counts_sqrt_normalized = csr_matrix(
(np.sqrt(counts[cluster_names_sorted] / nb_examples),
(np.arange(K_nb_cluster), np.arange(K_nb_cluster))))
diag_counts_sqrt = np.sqrt(counts[cluster_names_sorted])
# set it as first factor
op_factors.set_factor(0, diag_counts_sqrt_normalized)
if hierarchical_inside:
_lambda_tmp, op_factors, _, objective_palm, array_objective_hierarchical = \
hierarchical_palm4msa(
arr_X_target=diag_counts_sqrt[:, None,] * X_centroids_hat,
lst_S_init=op_factors.get_list_of_factors(),
lst_dct_projection_function=lst_proj_op_by_fac_step,
f_lambda_init=_lambda * np.sqrt(nb_examples),
nb_iter=nb_iter_palm,
update_right_to_left=True,
residual_on_right=residual_on_right,
return_objective_function=track_objective_palm,
track_objective_palm=track_objective_palm,
delta_objective_error_threshold_palm=delta_objective_error_threshold_inner_palm)
else:
_lambda_tmp, op_factors, _, objective_palm, nb_iter_palm = \
palm4msa(arr_X_target=diag_counts_sqrt[:, None,] * X_centroids_hat,
lst_S_init=op_factors.get_list_of_factors(),
nb_factors=op_factors.n_factors,
lst_projection_functions=lst_proj_op_by_fac_step[-1][
"finetune"],
f_lambda_init=_lambda * np.sqrt(nb_examples),
nb_iter=nb_iter_palm,
update_right_to_left=True,
track_objective=track_objective_palm,
delta_objective_error_threshold=delta_objective_error_threshold_inner_palm)
lst_all_objective_functions_palm.append(objective_palm)
_lambda = _lambda_tmp / np.sqrt(nb_examples)
objective_function[i_iter] = compute_objective(X_data, op_centroids, indicator_vector)
if i_iter >= 1:
delta_objective_error = np.abs(objective_function[i_iter] - objective_function[i_iter-1]) / objective_function[i_iter-1]
# todo vérifier que l'erreur absolue est plus petite que le threshold plusieurs fois d'affilee
i_iter += 1
lst_factors_ = op_factors.get_list_of_factors()
op_centroids = SparseFactors([lst_factors_[1] * _lambda] + lst_factors_[2:])
return objective_function[:i_iter], op_centroids, indicator_vector, lst_all_objective_functions_palm
def kmeans_minibatch(X_data, K_nb_cluster, nb_iter, initialization,
batch_size):
"""
:param X_data: The data matrix of n examples in dimensions d in shape (n, d).
:param K_nb_cluster: The number of clusters to look for.
:param nb_iter: The maximum number of iteration.
:param initialization: The (K, d) matrix of centroids at initialization.
:param batch_size: The size of each batch.
:return:
"""
X_data_norms = get_squared_froebenius_norm_line_wise(X_data)
# Initialize our centroids by picking random data points
U_centroids_hat = copy.deepcopy(initialization)
U_centroids = U_centroids_hat
full_indicator_vector = np.zeros(X_data.shape[0], dtype=int)
full_count_vector = np.zeros(K_nb_cluster, dtype=int)
objective_function = np.empty((nb_iter, ))
# Loop for the maximum number of iterations
i_iter = 0
delta_objective_error_threshold = 1e-6
delta_objective_error = np.inf
while True:
for i_iter, example_batch_indexes in enumerate(
DataGenerator(X_data,
batch_size=batch_size,
return_indexes=True)):
if not (delta_objective_error > delta_objective_error_threshold):
logger.info(
"not (delta_objective_error {}-{}={} > delta_objective_error_threshold {})"
.format(objective_function[i_iter],
objective_function[i_iter - 1],
delta_objective_error,
delta_objective_error_threshold))
break
example_batch = X_data[example_batch_indexes]
logger.info("Iteration Kmeans {}".format(i_iter))
indicator_vector, distances = assign_points_to_clusters(
example_batch,
U_centroids,
X_norms=X_data_norms[example_batch_indexes])
full_indicator_vector[example_batch_indexes] = indicator_vector
cluster_names, counts = np.unique(indicator_vector,
return_counts=True)
# cluster_names_sorted = np.argsort(cluster_names)
#
count_vector = np.zeros(K_nb_cluster, dtype=int)
count_vector[cluster_names] = counts
full_count_vector += count_vector
# previous_full_count_vector = full_count_vector - count_vector
# Update centroid location using the newly
# assigned data point classes
# This way of updating the centroids (centroid index wise) is better than the one proposed in the paper "Web-Scale K-Means Clustering"
# as the number of update with always be <= batch_size
for c in range(K_nb_cluster):
if full_count_vector[c] != 0 and count_vector[c] != 0:
U_centroids_hat[c] += (1 / full_count_vector[c]) * np.sum(
example_batch[indicator_vector == c] -
U_centroids_hat[c],
axis=0)
# this is exactly equivalent to an update of the mean:
# U_centroids_hat[c] = (previous_full_count_vector[c] / full_count_vector[c]) * U_centroids_hat[c] + (1 / full_count_vector[c]) * np.sum(example_batch[indicator_vector == c], axis=0)
# for i_ex, ex in enumerate(example_batch):
# c = indicator_vector[i_ex]
# full_count_vector[c] += 1
# eta = 1./full_count_vector[c]
# U_centroids_hat[c] = (1-eta) * U_centroids_hat[c] + eta * ex
# counts, cluster_names_sorted = assess_clusters_integrity(X_data,
# X_data_norms,
# U_centroids_hat,
# K_nb_cluster,
# counts,
# indicator_vector,
# distances,
# cluster_names,
# cluster_names_sorted)
# check if all clusters still have points
# for c in range(K_nb_cluster):
# biggest_cluster_index = np.argmax(counts) # type: int
# biggest_cluster = cluster_names[biggest_cluster_index]
# biggest_cluster_data = X_data[indicator_vector == biggest_cluster]
#
# cluster_data = X_data[indicator_vector == c]
# if len(cluster_data) == 0:
# logger.warning("cluster has lost data, add new cluster. cluster idx: {}".format(c))
# U_centroids_hat[c] = biggest_cluster_data[np.random.randint(len(biggest_cluster_data))].reshape(1, -1)
# counts = list(counts)
# counts[biggest_cluster_index] -= 1
# counts.append(1)
# counts = np.array(counts)
# cluster_names_sorted = list(cluster_names_sorted)
# cluster_names_sorted.append(c)
# cluster_names_sorted = np.array(cluster_names_sorted)
# else:
# U_centroids_hat[c] = np.mean(X_data[indicator_vector == c], 0)
U_centroids = U_centroids_hat
objective_function[i_iter, ] = compute_objective(
X_data, U_centroids, full_indicator_vector)
if i_iter >= 1:
delta_objective_error = np.abs(
objective_function[i_iter] - objective_function[i_iter - 1]
) / objective_function[
i_iter -
1] # todo vérifier que l'erreur absolue est plus petite que le threshold plusieurs fois d'affilée
i_iter += 1
else:
continue
break
return objective_function[:i_iter], U_centroids, indicator_vector
def qmeans(X_data: np.ndarray,
K_nb_cluster: int,
nb_iter: int,
nb_factors: int,
params_palm4msa: dict,
initialization: np.ndarray,
hierarchical_inside=False,
graphical_display=False):
"""
:param X_data: The data matrix of n examples in dimensions d in shape (n, d).
:param K_nb_cluster: The number of clusters to look for.
:param nb_iter: The maximum number of iteration.
:param nb_factors: The number of factors for the decomposition.
:param initialization: The initial matrix of centroids not yet factorized.
:param params_palm4msa: The dictionnary of parameters for the palm4msa algorithm.
:param hierarchical_inside: Tell the algorithm if the hierarchical version of palm4msa should be used.
:param graphical_display: Tell the algorithm to display the results.
:return:
"""
assert K_nb_cluster == initialization.shape[0]
X_data_norms = get_squared_froebenius_norm_line_wise(X_data)
init_lambda = params_palm4msa["init_lambda"]
nb_iter_palm = params_palm4msa["nb_iter"]
lst_proj_op_by_fac_step = params_palm4msa["lst_constraint_sets"]
residual_on_right = params_palm4msa["residual_on_right"]
X_centroids_hat = copy.deepcopy(initialization)
min_K_d = min(X_centroids_hat.shape)
lst_factors = [np.eye(min_K_d) for _ in range(nb_factors)]
eye_norm = np.sqrt(K_nb_cluster)
lst_factors[0] = np.eye(K_nb_cluster) / eye_norm
lst_factors[1] = np.eye(K_nb_cluster, min_K_d)
lst_factors[-1] = np.zeros((min_K_d, X_centroids_hat.shape[1]))
if graphical_display:
lst_factors_init = copy.deepcopy(lst_factors)
_lambda_tmp, lst_factors, U_centroids, nb_iter_by_factor, objective_palm = hierarchical_palm4msa(
arr_X_target=np.eye(K_nb_cluster) @ X_centroids_hat,
lst_S_init=lst_factors,
lst_dct_projection_function=lst_proj_op_by_fac_step,
f_lambda_init=init_lambda * eye_norm,
nb_iter=nb_iter_palm,
update_right_to_left=True,
residual_on_right=residual_on_right,
graphical_display=False)
_lambda = _lambda_tmp / eye_norm
if graphical_display:
if hierarchical_inside:
plt.figure()
plt.yscale("log")
plt.scatter(np.arange(len(objective_palm) * 3, step=3),
objective_palm[:, 0],
marker="x",
label="before split")
plt.scatter(np.arange(len(objective_palm) * 3, step=3) + 1,
objective_palm[:, 1],
marker="x",
label="between")
plt.scatter(np.arange(len(objective_palm) * 3, step=3) + 2,
objective_palm[:, 2],
marker="x",
label="after finetune")
plt.plot(np.arange(len(objective_palm) * 3),
objective_palm.flatten(),
color="k")
plt.legend()
plt.show()
visual_evaluation_palm4msa(
np.eye(K_nb_cluster) @ X_centroids_hat, lst_factors_init,
lst_factors, _lambda * multi_dot(lst_factors))
objective_function = np.empty((nb_iter, 2))
# Loop for the maximum number of iterations
i_iter = 0
delta_objective_error_threshold = 1e-6
delta_objective_error = np.inf
while (i_iter <= 1) or (
(i_iter < nb_iter) and
(delta_objective_error > delta_objective_error_threshold)):
logger.info("Iteration Qmeans {}".format(i_iter))
U_centroids = _lambda * multi_dot(lst_factors[1:])
if i_iter > 0:
objective_function[i_iter,
0] = compute_objective(X_data, U_centroids,
indicator_vector)
# Assign all points to the nearest centroid
# first get distance from all points to all centroids
distances = get_distances(X_data,
U_centroids,
precomputed_data_points_norm=X_data_norms)
# then, Determine class membership of each point
# by picking the closest centroid
indicator_vector = np.argmin(distances, axis=1)
objective_function[i_iter,
1] = compute_objective(X_data, U_centroids,
indicator_vector)
# Update centroid location using the newly
# assigned data point classes
for c in range(K_nb_cluster):
X_centroids_hat[c] = np.mean(X_data[indicator_vector == c], 0)
# get the number of observation in each cluster
cluster_names, counts = np.unique(indicator_vector, return_counts=True)
cluster_names_sorted = np.argsort(cluster_names)
if len(counts) < K_nb_cluster:
raise ValueError(
"Some clusters have no point. Aborting iteration {}".format(
i_iter))
diag_counts_sqrt = np.diag(np.sqrt(
counts[cluster_names_sorted])) # todo use sparse matrix object
diag_counts_sqrt_norm = np.linalg.norm(
diag_counts_sqrt
) # todo analytic sqrt(n) instead of cumputing it with norm
diag_counts_sqrt_normalized = diag_counts_sqrt / diag_counts_sqrt_norm
# set it as first factor
lst_factors[0] = diag_counts_sqrt_normalized
if graphical_display:
lst_factors_init = copy.deepcopy(lst_factors)
if hierarchical_inside:
_lambda_tmp, lst_factors, _, nb_iter_by_factor, objective_palm = hierarchical_palm4msa(
arr_X_target=diag_counts_sqrt @ X_centroids_hat,
lst_S_init=lst_factors,
lst_dct_projection_function=lst_proj_op_by_fac_step,
# f_lambda_init=_lambda,
f_lambda_init=_lambda * diag_counts_sqrt_norm,
nb_iter=nb_iter_palm,
update_right_to_left=True,
residual_on_right=residual_on_right,
graphical_display=False)
loss_palm_before = objective_palm[0, 0]
loss_palm_after = objective_palm[-1, -1]
else:
_lambda_tmp, lst_factors, _, objective_palm, nb_iter_palm = palm4msa(
arr_X_target=diag_counts_sqrt @ X_centroids_hat,
lst_S_init=lst_factors,
nb_factors=len(lst_factors),
lst_projection_functions=lst_proj_op_by_fac_step[-1]
["finetune"],
f_lambda_init=_lambda * diag_counts_sqrt_norm,
nb_iter=nb_iter_palm,
update_right_to_left=True,
graphical_display=False)
loss_palm_before = objective_palm[0, -1]
loss_palm_after = objective_palm[-1, -1]
logger.debug("Loss palm before: {}".format(loss_palm_before))
logger.debug("Loss palm after: {}".format(loss_palm_after))
if graphical_display:
if hierarchical_inside:
plt.figure()
plt.yscale("log")
plt.scatter(np.arange(len(objective_palm) * 3, step=3),
objective_palm[:, 0],
marker="x",
label="before split")
plt.scatter(np.arange(len(objective_palm) * 3, step=3) + 1,
objective_palm[:, 1],
marker="x",
label="between")
plt.scatter(np.arange(len(objective_palm) * 3, step=3) + 2,
objective_palm[:, 2],
marker="x",
label="after finetune")
plt.plot(np.arange(len(objective_palm) * 3),
objective_palm.flatten(),
color="k")
plt.legend()
plt.show()
visual_evaluation_palm4msa(diag_counts_sqrt @ X_centroids_hat,
lst_factors_init, lst_factors,
_lambda_tmp * multi_dot(lst_factors))
_lambda = _lambda_tmp / diag_counts_sqrt_norm
logger.debug("Returned loss (with diag) palm: {}".format(
objective_palm[-1, 0]))
if i_iter >= 2:
delta_objective_error = np.abs(
objective_function[i_iter, 0] -
objective_function[i_iter - 1, 0]
) / objective_function[
i_iter - 1,
0] # todo vérifier que l'erreur absolue est plus petite que le threshold plusieurs fois d'affilée
i_iter += 1
U_centroids = _lambda * multi_dot(lst_factors[1:])
distances = get_distances(X_data,
U_centroids,
precomputed_data_points_norm=X_data_norms)
indicator_vector = np.argmin(distances, axis=1)
return objective_function[:i_iter], U_centroids, indicator_vector
def kmeans(X_data,
K_nb_cluster,
nb_iter,
initialization,
delta_objective_error_threshold=1e-6,
proj_l1=False,
_lambda=None,
epsilon=None):
"""
:param X_data: The data matrix of n examples in dimensions d in shape (n, d).
:param K_nb_cluster: The number of clusters to look for.
:param nb_iter: The maximum number of iteration.
:param initialization: The (K, d) matrix of centroids at initialization.
:param delta_objective_error_threshold: The normalized difference between the error criterion at 2 successive step must be greater or equal to that value.
:return:
"""
X_data_norms = get_squared_froebenius_norm_line_wise(X_data)
# Initialize our centroids by picking random data points
U_centroids_hat = copy.deepcopy(initialization)
U_centroids = U_centroids_hat
objective_function = np.empty((nb_iter, ))
# Loop for the maximum number of iterations
i_iter = 0
delta_objective_error = np.inf
while (i_iter == 0) or (
(i_iter < nb_iter) and
(delta_objective_error > delta_objective_error_threshold)):
logger.info("Iteration Kmeans {}".format(i_iter))
indicator_vector, distances = assign_points_to_clusters(
X_data, U_centroids, X_norms=X_data_norms)
cluster_names, counts = np.unique(indicator_vector, return_counts=True)
cluster_names_sorted = np.argsort(cluster_names)
# Update centroid location using the new indicator vector
counts, cluster_names_sorted = update_clusters_with_integrity_check(
X_data, X_data_norms, U_centroids_hat, K_nb_cluster, counts,
indicator_vector, distances, cluster_names, cluster_names_sorted)
U_centroids = U_centroids_hat
if proj_l1:
if _lambda is None or epsilon is None:
raise ValueError(
"epsilon and lambda must be set if proj_l1 is True")
for i_centroid, centroid in enumerate(U_centroids):
U_centroids[i_centroid, :] = proj_onto_l1_ball(
_lambda=_lambda, epsilon_tol=epsilon, vec=centroid)
objective_function[i_iter, ] = compute_objective(
X_data, U_centroids, indicator_vector)
if i_iter >= 1:
delta_objective_error = np.abs(objective_function[i_iter] -
objective_function[i_iter - 1]
) / objective_function[i_iter - 1]
i_iter += 1
return objective_function[:i_iter], U_centroids, indicator_vector