def predict(spectral_net, x, y, n_clusters):
x_spectralnet = spectral_net.predict(x)
kmeans_assignments, km = get_cluster_sols(x_spectralnet, ClusterClass=KMeans, n_clusters=n_clusters, init_args={'n_init':10})
y_spectralnet, _ = get_y_preds(kmeans_assignments, y, n_clusters)
return x_spectralnet, y_spectralnet
def fit(self, x, y):
if self.cluster_obj is None:
self.cluster_obj = self.ClusterClass(self.n_clusters,
**self.init_args)
for _ in range(10):
try:
self.cluster_obj.fit(x)
break
except:
print("Unexpected error:", sys.exc_info())
else:
return np.zeros((len(x), ))
cluster_assignments = self.cluster_obj.predict(x)
_, confusion_matrix, kmeans_to_true_cluster_labels = get_y_preds(
cluster_assignments, y, self.n_clusters)
_, self.kmeans_to_true_cluster_labels = get_y_preds_from_cm(
cluster_assignments, self.n_clusters, confusion_matrix)
return self
def run_net(data, params):
#
# UNPACK DATA
#
x_train, y_train, x_val, y_val, x_test, y_test = data['spectral'][
'train_and_test']
x_train_unlabeled, y_train_unlabeled, x_train_labeled, y_train_labeled = data[
'spectral']['train_unlabeled_and_labeled']
x_val_unlabeled, y_val_unlabeled, x_val_labeled, y_val_labeled = data[
'spectral']['val_unlabeled_and_labeled']
if 'siamese' in params['affinity']:
pairs_train, dist_train, pairs_val, dist_val = data['siamese'][
'train_and_test']
x = np.concatenate((x_train, x_val, x_test), axis=0)
y = np.concatenate((y_train, y_val, y_test), axis=0)
if len(x_train_labeled):
y_train_labeled_onehot = OneHotEncoder().fit_transform(
y_train_labeled.reshape(-1, 1)).toarray()
else:
y_train_labeled_onehot = np.empty((0, len(np.unique(y))))
#
# SET UP INPUTS
#
# create true y placeholder (not used in unsupervised training)
y_true = tf.placeholder(tf.float32,
shape=(None, params['n_clusters']),
name='y_true')
batch_sizes = {
'Unlabeled': params['batch_size'],
'Labeled': params['batch_size'],
'Orthonorm': params.get('batch_size_orthonorm', params['batch_size']),
}
input_shape = x.shape[1:]
# spectralnet has three inputs -- they are defined here
inputs = {
'Unlabeled': Input(shape=input_shape, name='UnlabeledInput'),
'Labeled': Input(shape=input_shape, name='LabeledInput'),
'Orthonorm': Input(shape=input_shape, name='OrthonormInput'),
}
#
# DEFINE AND TRAIN SIAMESE NET
#
# run only if we are using a siamese network
if params['affinity'] == 'siamese':
siamese_net = networks.SiameseNet(inputs, params['arch'],
params.get('siam_reg'), y_true)
history = siamese_net.train(pairs_train, dist_train, pairs_val,
dist_val, params['siam_lr'],
params['siam_drop'],
params['siam_patience'], params['siam_ne'],
params['siam_batch_size'])
else:
siamese_net = None
#
# DEFINE AND TRAIN SPECTRALNET
#
spectral_net = networks.SpectralNet(inputs, params['arch'],
params.get('spec_reg'), y_true,
y_train_labeled_onehot,
params['n_clusters'],
params['affinity'],
params['scale_nbr'], params['n_nbrs'],
batch_sizes, siamese_net, x_train,
len(x_train_labeled))
spectral_net.train(x_train_unlabeled, x_train_labeled, x_val_unlabeled,
params['spec_lr'], params['spec_drop'],
params['spec_patience'], params['spec_ne'])
print("finished training")
#
# EVALUATE
#
# get final embeddings
x_spectralnet = spectral_net.predict(x)
# get accuracy and nmi
kmeans_assignments, km = get_cluster_sols(x_spectralnet,
ClusterClass=KMeans,
n_clusters=params['n_clusters'],
init_args={'n_init': 10})
y_spectralnet, _ = get_y_preds(kmeans_assignments, y, params['n_clusters'])
print_accuracy(kmeans_assignments, y, params['n_clusters'])
from sklearn.metrics import normalized_mutual_info_score as nmi
nmi_score = nmi(kmeans_assignments, y)
print('NMI: ' + str(np.round(nmi_score, 3)))
if params['generalization_metrics']:
x_spectralnet_train = spectral_net.predict(x_train_unlabeled)
x_spectralnet_test = spectral_net.predict(x_test)
km_train = KMeans(
n_clusters=params['n_clusters']).fit(x_spectralnet_train)
from scipy.spatial.distance import cdist
dist_mat = cdist(x_spectralnet_test, km_train.cluster_centers_)
closest_cluster = np.argmin(dist_mat, axis=1)
print_accuracy(closest_cluster, y_test, params['n_clusters'],
' generalization')
nmi_score = nmi(closest_cluster, y_test)
print('generalization NMI: ' + str(np.round(nmi_score, 3)))
return x_spectralnet, y_spectralnet
def run_net(data, params):
#
# UNPACK DATA
#
x_train_unlabeled, y_train_unlabeled, x_val, y_val, x_test, y_test = data[
'spectral']['train_and_test']
print(params['input_shape'])
inputs_vae = Input(shape=params['input_shape'], name='inputs_vae')
ConvAE = Conv.ConvAE(inputs_vae, params)
try:
ConvAE.vae.load_weights('vae_mnist.h5')
except OSError:
print('No pretrained weights available...')
lh = LearningHandler(lr=params['spec_lr'],
drop=params['spec_drop'],
lr_tensor=ConvAE.learning_rate,
patience=params['spec_patience'])
lh.on_train_begin()
n_epochs = 5000
losses_vae = np.empty((n_epochs, ))
homo_plot = np.empty((n_epochs, ))
nmi_plot = np.empty((n_epochs, ))
ari_plot = np.empty((n_epochs, ))
y_val = np.squeeze(np.asarray(y_val).ravel()) # squeeze into 1D array
start_time = time.time()
for i in range(n_epochs):
# if i==0:
x_recon, _, x_val_y = ConvAE.vae.predict(x_val)
losses_vae[i] = ConvAE.train_vae(x_val, x_val_y, params['batch_size'])
#x_val_y = ConvAE.vae.predict(x_val)[2]
#y_sp = x_val_y.argmax(axis=1)
#print_accuracy(y_sp, y_val, params['n_clusters'])
print("Epoch: {}, loss={:2f}".format(i, losses_vae[i]))
os.makedirs('vae', exist_ok=True)
os.makedirs('vae_umap', exist_ok=True)
fig, axs = plt.subplots(3, 4, figsize=(25, 18))
fig.subplots_adjust(wspace=0.25)
embedding = ConvAE.encoder.predict(x_val)
kmeans = KMeans(n_clusters=params['n_clusters'], n_init=30)
predicted_labels = kmeans.fit_predict(
embedding) # cluster on current embeddings for metric eval
_, confusion_matrix = get_y_preds(predicted_labels, y_val,
params['n_clusters'])
homo_plot[i] = metrics.acc(y_val, predicted_labels)
nmi_plot[i] = metrics.nmi(y_val, predicted_labels)
ari_plot[i] = metrics.ari(y_val, predicted_labels)
tsne = manifold.TSNE(n_components=2, init='pca', random_state=0)
Z_tsne = tsne.fit_transform(embedding)
sc = axs[1][0].scatter(Z_tsne[:, 0],
Z_tsne[:, 1],
s=2,
c=y_train_unlabeled,
cmap=plt.cm.get_cmap("jet", 14))
axs[1][0].set_title('t-SNE Embeddings')
axs[1][0].set_xlabel('t-SNE 1')
axs[1][0].set_ylabel('t-SNE 2')
axs[1][0].set_xticks([])
axs[1][0].set_yticks([])
axs[1][0].spines['right'].set_visible(False)
axs[1][0].spines['top'].set_visible(False)
divider = make_axes_locatable(axs[1][0])
cax = divider.append_axes('right', size='15%', pad=0.05)
cbar = fig.colorbar(sc,
cax=cax,
orientation='vertical',
ticks=range(params['n_clusters']))
cbar.ax.set_yticklabels(
params['cluster_names']) # vertically oriented colorbar
# Create offset transform by 5 points in x direction
dx = 0 / 72.
dy = -5 / 72.
offset = matplotlib.transforms.ScaledTranslation(
dx, dy, fig.dpi_scale_trans)
# apply offset transform to all cluster ticklabels.
for label in cbar.ax.yaxis.get_majorticklabels():
label.set_transform(label.get_transform() + offset)
reducer = umap.UMAP(transform_seed=36, random_state=36)
matrix_reduce = reducer.fit_transform(embedding)
sc = axs[1][1].scatter(matrix_reduce[:, 0],
matrix_reduce[:, 1],
s=2,
c=y_train_unlabeled,
cmap=plt.cm.get_cmap("jet", 14))
axs[1][1].set_title('UMAP Embeddings')
axs[1][1].set_xlabel('UMAP 1')
axs[1][1].set_ylabel('UMAP 2')
axs[1][1].set_xticks([])
axs[1][1].set_yticks([])
# Hide the right and top spines
axs[1][1].spines['right'].set_visible(False)
axs[1][1].spines['top'].set_visible(False)
im = axs[1][2].imshow(confusion_matrix, cmap='YlOrRd')
axs[1][2].set_title('Confusion Matrix')
axs[1][2].set_xticks(range(params['n_clusters']))
axs[1][2].set_yticks(range(params['n_clusters']))
axs[1][2].set_xticklabels(params['cluster_names'], fontsize=8)
axs[1][2].set_yticklabels(params['cluster_names'], fontsize=8)
divider = make_axes_locatable(axs[1][2])
cax = divider.append_axes('right', size='10%', pad=0.05)
cbar = fig.colorbar(im, cax=cax, orientation='vertical', ticks=[])
axs[0][0].plot(losses_vae[:i + 1])
axs[0][0].set_title('VAE Loss')
axs[0][0].set_xlabel('epochs')
axs[0][1].plot(homo_plot[:i + 1])
axs[0][1].set_title('Homogeneity')
axs[0][1].set_xlabel('epochs')
axs[0][1].set_ylim(0, 1)
axs[0][2].plot(ari_plot[:i + 1])
axs[0][2].set_title('ARI')
axs[0][2].set_xlabel('epochs')
axs[0][2].set_ylim(0, 1)
axs[0][3].plot(nmi_plot[:i + 1])
axs[0][3].set_title('NMI')
axs[0][3].set_xlabel('epochs')
axs[0][3].set_ylim(0, 1)
#reconstructed_cell = ConvAE.vae.predict(x_val[:1, ...])[0, ..., 0]
cell_tile = x_val[0, ..., 0]
cell_tile = cell_tile[:, :64]
x_recon = x_recon[0, ..., 0]
reconstructed_cell_tile = x_recon[:, :64]
reconstructed_cell_tile = np.flipud(reconstructed_cell_tile)
cell_heatmap = np.vstack((cell_tile, reconstructed_cell_tile))
axs[1][3].imshow(cell_heatmap, cmap='Reds')
axs[1][3].set_xticks([])
axs[1][3].set_yticks([])
axs[1][3].spines['right'].set_visible(False)
axs[1][3].spines['top'].set_visible(False)
axs[1][3].spines['left'].set_visible(False)
axs[1][3].spines['bottom'].set_visible(False)
# get eigenvalues and eigenvectors
scale = get_scale(embedding, params['batch_size'], params['scale_nbr'])
values, vectors = spectral_clustering(embedding, scale,
params['n_nbrs'],
params['affinity'])
# sort, then store the top n_clusters=2
values_idx = np.argsort(values)
x_spectral_clustering = vectors[:, values_idx[:params['n_clusters']]]
# do kmeans clustering in this subspace
y_spectral_clustering = KMeans(
n_clusters=params['n_clusters']).fit_predict(
vectors[:, values_idx[:params['n_clusters']]])
tsne = manifold.TSNE(n_components=2, init='pca', random_state=0)
Z_tsne = tsne.fit_transform(x_spectral_clustering)
sc = axs[2][0].scatter(Z_tsne[:, 0],
Z_tsne[:, 1],
s=2,
c=y_train_unlabeled,
cmap=plt.cm.get_cmap("jet", 14))
axs[2][0].set_title('Spectral Clusters (t-SNE) True Labels')
axs[2][0].set_xlabel('t-SNE 1')
axs[2][0].set_ylabel('t-SNE 2')
axs[2][0].set_xticks([])
axs[2][0].set_yticks([])
axs[2][0].spines['right'].set_visible(False)
axs[2][0].spines['top'].set_visible(False)
reducer = umap.UMAP(transform_seed=36, random_state=36)
matrix_reduce = reducer.fit_transform(x_spectral_clustering)
axs[2][1].scatter(matrix_reduce[:, 0],
matrix_reduce[:, 1],
s=2,
c=y_spectral_clustering,
cmap=plt.cm.get_cmap("jet", 14))
axs[2][1].set_title('Spectral Clusters (UMAP)')
axs[2][1].set_xlabel('UMAP 1')
axs[2][1].set_ylabel('UMAP 2')
axs[2][1].set_xticks([])
axs[2][1].set_yticks([])
# Hide the right and top spines
axs[2][1].spines['right'].set_visible(False)
axs[2][1].spines['top'].set_visible(False)
axs[2][2].scatter(matrix_reduce[:, 0],
matrix_reduce[:, 1],
s=2,
c=y_train_unlabeled,
cmap=plt.cm.get_cmap("jet", 14))
axs[2][2].set_title('True Labels (UMAP)')
axs[2][2].set_xlabel('UMAP 1')
axs[2][2].set_ylabel('UMAP 2')
axs[2][2].set_xticks([])
axs[2][2].set_yticks([])
# Hide the right and top spines
axs[2][2].spines['right'].set_visible(False)
axs[2][2].spines['top'].set_visible(False)
axs[2][3].hist(x_spectral_clustering)
axs[2][3].set_title("histogram of true eigenvectors")
train_time = str(
datetime.timedelta(seconds=(int(time.time() - start_time))))
n_matrices = (i + 1) * params['batch_size'] * 100
fig.suptitle('Trained on ' + '{:,}'.format(n_matrices) + ' cells\n' +
train_time)
plt.savefig('vae/%d.png' % i)
plt.close()
plt.close()
if i > 1:
if np.abs(losses_vae[i] - losses_vae[i - 1]) < 0.0001:
print('STOPPING EARLY')
break
print("finished training")
plt.plot(losses_vae)
plt.title('VAE Loss')
plt.show()
x_val_y = ConvAE.vae.predict(x_val)[2]
# x_val_y = ConvAE.classfier.predict(x_val_lp)
y_sp = x_val_y.argmax(axis=1)
print_accuracy(y_sp, y_val, params['n_clusters'])
from sklearn.metrics import normalized_mutual_info_score as nmi
y_val = np.squeeze(np.asarray(y_val).ravel()) # squeeze into 1D array
print(y_sp.shape, y_val.shape)
nmi_score1 = nmi(y_sp, y_val)
print('NMI: ' + str(np.round(nmi_score1, 4)))
embedding = ConvAE.encoder.predict(x_val)
tsne = manifold.TSNE(n_components=2, init='pca', random_state=0)
Z_tsne = tsne.fit_transform(embedding)
fig = plt.figure()
plt.scatter(Z_tsne[:, 0],
Z_tsne[:, 1],
s=2,
c=y_train_unlabeled,
cmap=plt.cm.get_cmap("jet", 14))
plt.colorbar(ticks=range(params['n_clusters']))
plt.show()
def run_net(data, params):
#
# UNPACK DATA
#
x_train, y_train, x_val, y_val, x_test, y_test = data['spectral'][
'train_and_test']
x_train_unlabeled, y_train_unlabeled, x_train_labeled, y_train_labeled = data[
'spectral']['train_unlabeled_and_labeled']
x_val_unlabeled, y_val_unlabeled, x_val_labeled, y_val_labeled = data[
'spectral']['val_unlabeled_and_labeled']
if 'siamese' in params['affinity']:
pairs_train, dist_train, pairs_val, dist_val = data['siamese'][
'train_and_test']
x = np.concatenate((x_train, x_val, x_test), axis=0)
y = np.concatenate((y_train, y_val, y_test), axis=0)
X = x
n_samples, n_features = X.shape
def plot_embedding(X, title=None):
x_min, x_max = np.min(X, 0), np.max(X, 0)
X = (X - x_min) / (x_max - x_min)
plt.figure(figsize=(12, 12))
ax = plt.subplot(111)
for i in range(X.shape[0]):
plt.text(X[i, 0],
X[i, 1],
'.',
color=plt.cm.Set1(1),
fontdict={
'weight': 'bold',
'size': 20
})
plt.xticks([]), plt.yticks([])
if title is not None:
plt.title(title)
from sklearn import manifold
tsne = manifold.TSNE(n_components=2, init='pca', random_state=0)
start_time = time.time()
X_tsne = tsne.fit_transform(X)
plot_embedding(X_tsne)
plt.show()
if len(x_train_labeled):
y_train_labeled_onehot = OneHotEncoder().fit_transform(
y_train_labeled.reshape(-1, 1)).toarray()
else:
y_train_labeled_onehot = np.empty((0, len(np.unique(y))))
#
# SET UP INPUTS
#
# create true y placeholder (not used in unsupervised training)
y_true = tf.placeholder(tf.float32,
shape=(None, params['n_clusters']),
name='y_true')
batch_sizes = {
'Unlabeled': params['batch_size'],
'Labeled': params['batch_size'],
'Orthonorm': params.get('batch_size_orthonorm', params['batch_size']),
}
input_shape = x.shape[1:]
# spectralnet has three inputs -- they are defined here
inputs = {
'Unlabeled': Input(shape=input_shape, name='UnlabeledInput'),
'Labeled': Input(shape=input_shape, name='LabeledInput'),
'Orthonorm': Input(shape=input_shape, name='OrthonormInput'),
}
#
# DEFINE AND TRAIN SIAMESE NET
#
# run only if we are using a siamese network
if params['affinity'] == 'siamese':
siamese_net = networks.SiameseNet(inputs, params['arch'],
params.get('siam_reg'), y_true)
history = siamese_net.train(pairs_train, dist_train, pairs_val,
dist_val, params['siam_lr'],
params['siam_drop'],
params['siam_patience'], params['siam_ne'],
params['siam_batch_size'])
else:
siamese_net = None
spectral_net = networks.SpectralNet(inputs, params['arch'],
params.get('spec_reg'), y_true,
y_train_labeled_onehot,
params['n_clusters'],
params['affinity'],
params['scale_nbr'], params['n_nbrs'],
batch_sizes, siamese_net, x_train,
len(x_train_labeled))
spectral_net.train(x_train_unlabeled, x_train_labeled, x_val_unlabeled,
params['spec_lr'], params['spec_drop'],
params['spec_patience'], params['spec_ne'])
print("finished training")
#
# EVALUATE
#
# get final embeddings
x_spectralnet = spectral_net.predict(x)
# get accuracy and nmi
kmeans_assignments, km = get_cluster_sols(x_spectralnet,
ClusterClass=KMeans,
n_clusters=params['n_clusters'],
init_args={'n_init': 10})
y_spectralnet, _, _1 = get_y_preds(kmeans_assignments, y,
params['n_clusters'])
print_accuracy(kmeans_assignments, y, params['n_clusters'])
from sklearn.metrics import normalized_mutual_info_score as nmi
nmi_score = nmi(kmeans_assignments, y)
print('NMI: ' + str(np.round(nmi_score, 3)))
if params['generalization_metrics']:
x_spectralnet_train = spectral_net.predict(x_train_unlabeled)
x_spectralnet_test = spectral_net.predict(x_test)
km_train = KMeans(
n_clusters=params['n_clusters']).fit(x_spectralnet_train)
from scipy.spatial.distance import cdist
dist_mat = cdist(x_spectralnet_test, km_train.cluster_centers_)
closest_cluster = np.argmin(dist_mat, axis=1)
print_accuracy(closest_cluster, y_test, params['n_clusters'],
' generalization')
nmi_score = nmi(closest_cluster, y_test)
print('generalization NMI: ' + str(np.round(nmi_score, 3)))
return x_spectralnet, y_spectralnet
def run_net(data, params):
#
# UNPACK DATA
#
x_train, y_train, x_val, y_val, x_test, y_test = data['spectral'][
'train_and_test']
x_train_unlabeled, y_train_unlabeled, x_train_labeled, y_train_labeled = data[
'spectral']['train_unlabeled_and_labeled']
x_val_unlabeled, y_val_unlabeled, x_val_labeled, y_val_labeled = data[
'spectral']['val_unlabeled_and_labeled']
if 'siamese' in params['affinity']:
pairs_train, dist_train, pairs_val, dist_val = data['siamese'][
'train_and_test']
x = np.concatenate((x_train, x_val, x_test), axis=0)
y = np.concatenate((y_train, y_val, y_test), axis=0)
if len(x_train_labeled):
y_train_labeled_onehot = OneHotEncoder().fit_transform(
y_train_labeled.reshape(-1, 1)).toarray()
else:
y_train_labeled_onehot = np.empty((0, len(np.unique(y))))
#
# SET UP INPUTS
#
# create true y placeholder (not used in unsupervised training)
y_true = tf.placeholder(tf.float32,
shape=(None, params['n_clusters']),
name='y_true')
batch_sizes = {
'Unlabeled': params['batch_size'],
'Labeled': params['batch_size'],
'Orthonorm': params.get('batch_size_orthonorm', params['batch_size']),
}
input_shape = x.shape[1:]
# spectralnet has three inputs -- they are defined here
inputs = {
'Unlabeled': Input(shape=input_shape, name='UnlabeledInput'),
'Labeled': Input(shape=input_shape, name='LabeledInput'),
'Orthonorm': Input(shape=input_shape, name='OrthonormInput'),
}
#
# DEFINE SIAMESE NET
#
# run only if we are using a siamese network
if params['affinity'] == 'siamese':
# set up the siamese network inputs as well
siamese_inputs = {
'A': inputs['Unlabeled'],
'B': Input(shape=input_shape),
'Labeled': inputs['Labeled'],
}
# generate layers
layers = []
layers += make_layer_list(params['arch'], 'siamese',
params.get('siam_reg'))
# create the siamese net
siamese_outputs = stack_layers(siamese_inputs, layers)
# add the distance layer
distance = Lambda(costs.euclidean_distance,
output_shape=costs.eucl_dist_output_shape)(
[siamese_outputs['A'], siamese_outputs['B']])
#create the distance model for training
siamese_net_distance = Model(
[siamese_inputs['A'], siamese_inputs['B']], distance)
#
# TRAIN SIAMESE NET
#
# compile the siamese network
siamese_net_distance.compile(loss=costs.contrastive_loss,
optimizer=RMSprop())
# create handler for early stopping and learning rate scheduling
siam_lh = LearningHandler(lr=params['siam_lr'],
drop=params['siam_drop'],
lr_tensor=siamese_net_distance.optimizer.lr,
patience=params['siam_patience'])
# initialize the training generator
train_gen_ = train_gen(pairs_train, dist_train,
params['siam_batch_size'])
# format the validation data for keras
validation_data = ([pairs_val[:, 0], pairs_val[:, 1]], dist_val)
# compute the steps per epoch
steps_per_epoch = int(len(pairs_train) / params['siam_batch_size'])
# train the network
hist = siamese_net_distance.fit_generator(
train_gen_,
epochs=params['siam_ne'],
validation_data=validation_data,
steps_per_epoch=steps_per_epoch,
callbacks=[siam_lh])
# compute the siamese embeddings of the input data
all_siam_preds = train.predict(siamese_outputs['A'],
x_unlabeled=x_train,
inputs=inputs,
y_true=y_true,
batch_sizes=batch_sizes)
#
# DEFINE SPECTRALNET
#
# generate layers
layers = []
layers = make_layer_list(params['arch'][:-1], 'spectral',
params.get('spec_reg'))
layers += [{
'type': 'tanh',
'size': params['n_clusters'],
'l2_reg': params.get('spec_reg'),
'name': 'spectral_{}'.format(len(params['arch']) - 1)
}, {
'type': 'Orthonorm',
'name': 'orthonorm'
}]
# create spectralnet
outputs = stack_layers(inputs, layers)
spectral_net = Model(inputs=inputs['Unlabeled'],
outputs=outputs['Unlabeled'])
#
# DEFINE SPECTRALNET LOSS
#
# generate affinity matrix W according to params
if params['affinity'] == 'siamese':
input_affinity = tf.concat(
[siamese_outputs['A'], siamese_outputs['Labeled']], axis=0)
x_affinity = all_siam_preds
elif params['affinity'] in ['knn', 'full']:
input_affinity = tf.concat([inputs['Unlabeled'], inputs['Labeled']],
axis=0)
x_affinity = x_train
# calculate scale for affinity matrix
scale = get_scale(x_affinity, batch_sizes['Unlabeled'],
params['scale_nbr'])
# create affinity matrix
if params['affinity'] == 'full':
W = costs.full_affinity(input_affinity, scale=scale)
elif params['affinity'] in ['knn', 'siamese']:
W = costs.knn_affinity(input_affinity,
params['n_nbrs'],
scale=scale,
scale_nbr=params['scale_nbr'])
# if we have labels, use them
if len(x_train_labeled):
# get true affinities (from labeled data)
W_true = tf.cast(tf.equal(costs.squared_distance(y_true), 0),
dtype='float32')
# replace lower right corner of W with W_true
unlabeled_end = tf.shape(inputs['Unlabeled'])[0]
W_u = W[:unlabeled_end, :] # upper half
W_ll = W[unlabeled_end:, :unlabeled_end] # lower left
W_l = tf.concat((W_ll, W_true), axis=1) # lower half
W = tf.concat((W_u, W_l), axis=0)
# create pairwise batch distance matrix Dy
Dy = costs.squared_distance(
tf.concat([outputs['Unlabeled'], outputs['Labeled']], axis=0))
else:
Dy = costs.squared_distance(outputs['Unlabeled'])
# define loss
spectral_net_loss = K.sum(W * Dy) / (2 * params['batch_size'])
# create the train step update
learning_rate = tf.Variable(0., name='spectral_net_learning_rate')
train_step = tf.train.RMSPropOptimizer(
learning_rate=learning_rate).minimize(
spectral_net_loss, var_list=spectral_net.trainable_weights)
#
# TRAIN SPECTRALNET
#
# initialize spectralnet variables
K.get_session().run(
tf.variables_initializer(spectral_net.trainable_weights))
# set up validation/test set inputs
inputs_test = {
'Unlabeled': inputs['Unlabeled'],
'Orthonorm': inputs['Orthonorm']
}
# create handler for early stopping and learning rate scheduling
spec_lh = LearningHandler(lr=params['spec_lr'],
drop=params['spec_drop'],
lr_tensor=learning_rate,
patience=params['spec_patience'])
# begin spectralnet training loop
spec_lh.on_train_begin()
for i in range(params['spec_ne']):
# train spectralnet
loss = train.train_step(return_var=[spectral_net_loss],
updates=spectral_net.updates + [train_step],
x_unlabeled=x_train_unlabeled,
inputs=inputs,
y_true=y_true,
batch_sizes=batch_sizes,
x_labeled=x_train_labeled,
y_labeled=y_train_labeled_onehot,
batches_per_epoch=100)[0]
# get validation loss
val_loss = train.predict_sum(spectral_net_loss,
x_unlabeled=x_val_unlabeled,
inputs=inputs,
y_true=y_true,
x_labeled=x[0:0],
y_labeled=y_train_labeled_onehot,
batch_sizes=batch_sizes)
# do early stopping if necessary
if spec_lh.on_epoch_end(i, val_loss):
print('STOPPING EARLY')
break
# print training status
print("Epoch: {}, loss={:2f}, val_loss={:2f}".format(
i, loss, val_loss))
print("finished training")
#
# EVALUATE
#
# get final embeddings
x_spectralnet = train.predict(outputs['Unlabeled'],
x_unlabeled=x,
inputs=inputs_test,
y_true=y_true,
x_labeled=x_train_labeled[0:0],
y_labeled=y_train_labeled_onehot[0:0],
batch_sizes=batch_sizes)
# get accuracy and nmi
kmeans_assignments, km = get_cluster_sols(x_spectralnet,
ClusterClass=KMeans,
n_clusters=params['n_clusters'],
init_args={'n_init': 10})
y_spectralnet, _ = get_y_preds(kmeans_assignments, y, params['n_clusters'])
print_accuracy(kmeans_assignments, y, params['n_clusters'])
from sklearn.metrics import normalized_mutual_info_score as nmi
nmi_score = nmi(kmeans_assignments, y)
print('NMI: ' + str(np.round(nmi_score, 3)))
if params['generalization_metrics']:
x_spectralnet_train = train.predict(
outputs['Unlabeled'],
x_unlabeled=x_train_unlabeled,
inputs=inputs_test,
y_true=y_true,
x_labeled=x_train_labeled[0:0],
y_labeled=y_train_labeled_onehot[0:0],
batch_sizes=batch_sizes)
x_spectralnet_test = train.predict(
outputs['Unlabeled'],
x_unlabeled=x_test,
inputs=inputs_test,
y_true=y_true,
x_labeled=x_train_labeled[0:0],
y_labeled=y_train_labeled_onehot[0:0],
batch_sizes=batch_sizes)
km_train = KMeans(
n_clusters=params['n_clusters']).fit(x_spectralnet_train)
from scipy.spatial.distance import cdist
dist_mat = cdist(x_spectralnet_test, km_train.cluster_centers_)
closest_cluster = np.argmin(dist_mat, axis=1)
print_accuracy(closest_cluster, y_test, params['n_clusters'],
' generalization')
nmi_score = nmi(closest_cluster, y_test)
print('generalization NMI: ' + str(np.round(nmi_score, 3)))
return x_spectralnet, y_spectralnet