def inductive_step_hinsage(self, S, trained_model,
inductive_node_identifiers, batch_size):
"""
This function generates embeddings for unseen nodes using a trained hinsage model.
It returns the embeddings for these unseen nodes.
Parameters
----------
S : StellarGraph Object
The graph on which HinSAGE is deployed.
trained_model : Neural Network
The trained hinsage model, containing the trained and optimized aggregation functions per depth.
inductive_node_identifiers : list
Defines the nodes that HinSAGE needs to generate embeddings for
batch_size: int
batch size for the neural network in which HinSAGE is implemented.
"""
# The mapper feeds data from sampled subgraph to HinSAGE model
generator = HinSAGENodeGenerator(
S,
batch_size,
self.num_samples,
head_node_type=self.embedding_for_node_type)
test_gen_not_shuffled = generator.flow(inductive_node_identifiers,
shuffle=False)
inductive_emb = trained_model.predict(test_gen_not_shuffled, verbose=1)
inductive_emb = pd.DataFrame(inductive_emb,
index=inductive_node_identifiers)
return inductive_emb
def train_hinsage(self, S, node_identifiers, label, batch_size, epochs):
"""
This function trains a HinSAGE model, implemented in Tensorflow.
It returns the trained HinSAGE model and a pandas datarame containing the embeddings generated for the train nodes.
Parameters
----------
S : StellarGraph Object
The graph on which HinSAGE trains its aggregator functions.
node_identifiers : list
Defines the nodes that HinSAGE uses to train its aggregation functions.
label: Pandas dataframe
Defines the label of the nodes used for training, with the index representing the nodes.
batch_size: int
batch size to train the neural network in which HinSAGE is implemented.
epochs: int
Number of epochs for the neural network.
"""
# The mapper feeds data from sampled subgraph to GraphSAGE model
train_node_identifiers = node_identifiers[:round(0.8*len(node_identifiers))]
train_labels = label.loc[train_node_identifiers]
validation_node_identifiers = node_identifiers[round(0.8*len(node_identifiers)):]
validation_labels = label.loc[validation_node_identifiers]
generator = HinSAGENodeGenerator(S, batch_size, self.num_samples, head_node_type= self.embedding_for_node_type)
train_gen = generator.flow(train_node_identifiers, train_labels, shuffle=True)
test_gen = generator.flow(validation_node_identifiers, validation_labels)
# HinSAGE model
model = HinSAGE(layer_sizes=[self.embedding_size]*len(self.num_samples), generator=generator, dropout=0)
x_inp, x_out = model.build()
# Final estimator layer
prediction = layers.Dense(units=1, activation="sigmoid", dtype='float32')(x_out)
# Create Keras model for training
model = Model(inputs=x_inp, outputs=prediction)
model.compile(
optimizer=optimizers.Adam(lr=1e-3),
loss=binary_crossentropy,
)
# Train Model
model.fit(
train_gen, epochs=epochs, verbose=1, validation_data=test_gen, shuffle=False
)
trained_model = Model(inputs=x_inp, outputs=x_out)
train_gen_not_shuffled = generator.flow( node_identifiers, label, shuffle=False)
embeddings_train = trained_model.predict(train_gen_not_shuffled)
train_emb = pd.DataFrame(embeddings_train, index=node_identifiers)
return trained_model, train_emb
def create_HinSAGE_model(graph, link_prediction=False):
if link_prediction:
generator = HinSAGELinkGenerator(graph,
batch_size=2,
num_samples=[2, 1])
edge_ids_train = np.array([[1, 2], [2, 3], [1, 3]])
train_gen = generator.flow(edge_ids_train, np.array([1, 1, 0]))
else:
generator = HinSAGENodeGenerator(graph,
batch_size=2,
num_samples=[2, 2])
train_gen = generator.flow([1, 2], np.array([[1, 0], [0, 1]]))
base_model = HinSAGE(layer_sizes=[8, 8],
generator=train_gen,
bias=True,
dropout=0.5)
if link_prediction:
# Define input and output sockets of hinsage:
x_inp, x_out = base_model.build()
# Final estimator layer
prediction = link_regression(edge_embedding_method="ip")(x_out)
else:
x_inp, x_out = base_model.build()
prediction = layers.Dense(units=2, activation="softmax")(x_out)
keras_model = Model(inputs=x_inp, outputs=prediction)
return base_model, keras_model, generator, train_gen
def train(
G,
user_targets,
layer_size,
num_samples,
batch_size,
num_epochs,
learning_rate,
dropout,
):
"""
Train a HinSAGE model on the specified graph G with given parameters.
Args:
G: A StellarGraph object ready for machine learning
layer_size: A list of number of hidden nodes in each layer
num_samples: Number of neighbours to sample at each layer
batch_size: Size of batch for inference
num_epochs: Number of epochs to train the model
learning_rate: Initial Learning rate
dropout: The dropout (0->1)
"""
print(G.info())
# Split "user" nodes into train/test
# Split nodes into train/test using stratification.
train_targets, test_targets = model_selection.train_test_split(
user_targets, train_size=0.25, test_size=None
)
print("Train targets:\n", train_targets.iloc[:, 0].value_counts())
print("Test targets:\n", test_targets.iloc[:, 0].value_counts())
# The mapper feeds data from sampled subgraph to GraphSAGE model
generator = HinSAGENodeGenerator(G, batch_size, num_samples, head_node_type="user")
train_gen = generator.flow_from_dataframe(train_targets, shuffle=True)
test_gen = generator.flow_from_dataframe(test_targets)
# GraphSAGE model
model = HinSAGE(layer_sizes=layer_size, generator=generator, dropout=dropout)
x_inp, x_out = model.build()
# Final estimator layer
prediction = layers.Dense(units=train_targets.shape[1], activation="softmax")(x_out)
# The elite label is only true for a small fraction of the total users,
# so weight the training loss to ensure that model learns to predict
# the positive class.
# class_count = train_targets.values.sum(axis=0)
# weights = class_count.sum()/class_count
weights = [0.01, 1.0]
print("Weighting loss by: {}".format(weights))
# Create Keras model for training
model = keras.Model(inputs=x_inp, outputs=prediction)
model.compile(
optimizer=optimizers.Adam(lr=learning_rate),
loss=weighted_binary_crossentropy(weights),
metrics=[metrics.binary_accuracy],
)
# Train model
history = model.fit_generator(
train_gen, epochs=num_epochs, verbose=2, shuffle=False
)
# Evaluate on test set and print metrics
predictions = model.predict_generator(test_gen)
binary_predictions = predictions[:, 1] > 0.5
print("\nTest Set Metrics (on {} nodes)".format(len(predictions)))
# Calculate metrics using Scikit-Learn
cm = sk_metrics.confusion_matrix(test_targets.iloc[:, 1], binary_predictions)
print("Confusion matrix:")
print(cm)
accuracy = sk_metrics.accuracy_score(test_targets.iloc[:, 1], binary_predictions)
precision = sk_metrics.precision_score(test_targets.iloc[:, 1], binary_predictions)
recall = sk_metrics.recall_score(test_targets.iloc[:, 1], binary_predictions)
f1 = sk_metrics.f1_score(test_targets.iloc[:, 1], binary_predictions)
roc_auc = sk_metrics.roc_auc_score(test_targets.iloc[:, 1], binary_predictions)
print(
"accuracy = {:0.3}, precision = {:0.3}, recall = {:0.3}, f1 = {:0.3}".format(
accuracy, precision, recall, f1
)
)
print("ROC AUC = {:0.3}".format(roc_auc))
# Save model
save_str = "_n{}_l{}_d{}_r{}".format(
"_".join([str(x) for x in num_samples]),
"_".join([str(x) for x in layer_size]),
dropout,
learning_rate,
)
model.save("yelp_model" + save_str + ".h5")
def create_embeddings(node_type, num_samples, hinsage_layer_sizes, epochs,
patience, batch_size, dropout, activations):
# Check if num_samples and layer_size are compatible
assert len(hinsage_layer_sizes) == len(num_samples)
generator = HinSAGENodeGenerator(G,
batch_size,
num_samples=num_samples,
head_node_type=node_type)
# HinSAGE layers
hinsage = HinSAGE(layer_sizes=hinsage_layer_sizes,
activations=activations,
generator=generator,
bias=True,
normalize="l2",
dropout=dropout)
def run_deep_graph_infomax(base_model, generator, epochs, node_type):
corrupted_generator = CorruptedGenerator(generator)
gen = corrupted_generator.flow(G.nodes(node_type=node_type))
infomax = DeepGraphInfomax(base_model, corrupted_generator)
x_in, x_out = infomax.in_out_tensors()
print("Starting Training")
ttrain = time.time()
# Train
model = Model(inputs=x_in, outputs=x_out)
model.compile(loss=tf.nn.sigmoid_cross_entropy_with_logits,
optimizer=Adam(lr=1e-3))
es = EarlyStopping(monitor="loss", min_delta=0, patience=patience)
history = model.fit(gen,
epochs=epochs,
verbose=verbose,
callbacks=[es])
# sg.utils.plot_history(history)
ttrain1 = time.time()
print(
f"Training complete in {(ttrain1-ttrain):.2f} s ({(ttrain1-ttrain)/60:.2f} min)"
)
x_emb_in, x_emb_out = base_model.in_out_tensors()
# for full batch models, squeeze out the batch dim (which is 1)
if generator.num_batch_dims() == 2:
x_emb_out = tf.squeeze(x_emb_out, axis=0)
return x_emb_in, x_emb_out
# Run Deep Graph Infomax
x_emb_in, x_emb_out = run_deep_graph_infomax(hinsage,
generator,
epochs=epochs,
node_type=node_type)
emb_model = Model(inputs=x_emb_in, outputs=x_emb_out)
all_embeddings = emb_model.predict(
generator.flow(G.nodes(node_type=node_type)))
# TSNE visualization of embeddings
ttsne = time.time()
print("Creating TSNE")
embeddings_2d = pd.DataFrame(
TSNE(n_components=2).fit_transform(all_embeddings),
index=G.nodes(node_type=node_type))
# draw the points (colors based on ExtendedCaseGraphID)
node_ids = G.nodes(node_type=node_type).tolist()
ext_targets = v_sample.loc[[int(node_id) for node_id in node_ids
]].ExtendedCaseGraphID
label_map = {
l: i * 10
for i, l in enumerate(np.unique(ext_targets), start=10)
if pd.notna(l)
}
node_colours = [
label_map[target] if pd.notna(target) else 0
for target in ext_targets
]
ttsne1 = time.time()
print(
f"TSNE completed in {(ttsne1-ttsne):.2f} s ({(ttsne1-ttsne)/60:.2f} min)"
)
alpha = 0.7
fig, ax = plt.subplots(figsize=(15, 15))
ax.scatter(
embeddings_2d[0],
embeddings_2d[1],
c=node_colours,
cmap="jet",
alpha=alpha,
)
ax.set(aspect="equal")
plt.title(
f'TSNE visualization of HinSAGE "{node_type}" embeddings with Deep Graph Infomax'
)
plt.savefig(f"./embeddings/HinSAGE_DGI_embeddings_{node_type}.pdf")
return all_embeddings, embeddings_2d
def run_for_node_type(v_type, hinsage_layer_sizes, num_samples,
activations, epochs):
nan_tflag = data_splits[v_type].iloc[0].values[0]
train_tflag = data_splits[v_type].iloc[1].values[0]
test_tflag = data_splits[v_type].iloc[2].values[0]
train_cv_set = v_sets[v_type][nan_tflag:nan_tflag + train_tflag]
train_cv_ids = train_cv_set.index.values.tolist()
train_cv_labels = v_data.loc[[
int(node_id) for node_id in train_cv_ids
]].ExtendedCaseGraphID
test_set = v_sets[v_type][-test_tflag:]
test_ids = test_set.index.values.tolist()
generator = HinSAGENodeGenerator(G,
batch_size,
num_samples,
head_node_type=v_type)
hinsage = HinSAGE(layer_sizes=hinsage_layer_sizes,
activations=activations,
generator=generator,
bias=True,
normalize="l2",
dropout=dropout)
def run_deep_graph_infomax(base_model, generator, epochs):
print(f"Starting training for {v_type} type: ")
t0 = time.time()
corrupted_generator = CorruptedGenerator(generator)
gen = corrupted_generator.flow(G.nodes(node_type=v_type))
infomax = DeepGraphInfomax(base_model, corrupted_generator)
x_in, x_out = infomax.in_out_tensors()
# Train with DGI
model = Model(inputs=x_in, outputs=x_out)
model.compile(loss=tf.nn.sigmoid_cross_entropy_with_logits,
optimizer=Adam(lr=1e-3))
es = EarlyStopping(monitor="loss", min_delta=0, patience=10)
history = model.fit(gen,
epochs=epochs,
verbose=verbose,
callbacks=[es])
#sg.utils.plot_history(history)
x_emb_in, x_emb_out = base_model.in_out_tensors()
if generator.num_batch_dims() == 2:
x_emb_out = tf.squeeze(x_emb_out, axis=0)
t1 = time.time()
print(f'Time required: {t1-t0:.2f} s ({(t1-t0)/60:.1f} min)')
return x_emb_in, x_emb_out, model
#? Train HinSAGE model:
x_emb_in, x_emb_out, _model = run_deep_graph_infomax(hinsage,
generator,
epochs=epochs)
emb_model = Model(inputs=x_emb_in, outputs=x_emb_out)
train_cv_embs = emb_model.predict(
generator.flow(train_cv_set.index.values))
#? Optional: Plot embeddings of training and CV set of current node type
if (visualize == True):
train_cv_embs_2d = pd.DataFrame(
TSNE(n_components=2).fit_transform(train_cv_embs),
index=train_cv_set.index.values)
label_map = {
l: i * 10
for i, l in enumerate(np.unique(train_cv_labels), start=10)
if pd.notna(l)
}
node_colours = [
label_map[target] if pd.notna(target) else 0
for target in train_cv_labels
]
alpha = 0.7
fig, ax = plt.subplots(figsize=(15, 15))
ax.scatter(
train_cv_embs_2d[0],
train_cv_embs_2d[1],
c=node_colours,
cmap="jet",
alpha=alpha,
)
ax.set(aspect="equal")
plt.title(
f"TSNE of HinSAGE {v_type} embeddings with DGI- coloring on ExtendedCaseGraphID"
)
plt.show()
return 1
#? Split training and cross valuation set using 80% 20% simple ordered split
n_embs = train_cv_embs.shape[0]
train_size = int(n_embs * 0.80)
cv_size = int(n_embs * 0.20)
train_set = train_cv_embs[:train_size]
train_labels = np.ravel(
pd.DataFrame(train_cv_labels.values[:train_size]).fillna(0))
cv_set = train_cv_embs[-cv_size:]
cv_labels = np.ravel(
pd.DataFrame(train_cv_labels.values[-cv_size:]).fillna(0))
#? CLASSIFY
print(f"Running Classifier for {v_type} type")
classifier = DecisionTreeClassifier()
classifier.fit(
X=train_set,
y=train_labels,
)
cv_pred = classifier.predict(cv_set)
f1_avg = f1_score(cv_labels, cv_pred, average='weighted')
acc = (cv_pred == cv_labels).mean()
print(f"{v_type} CV Metrics: f1: {f1_avg:.6f} - acc: {acc:.6f}")
#? Now Run on test set
test_embs = emb_model.predict(generator.flow(test_set.index.values))
test_pred = classifier.predict(test_embs)
#? Save predictions
outdir = './output'
outname = f"{v_type}_predictions.csv"
if not os.path.exists(outdir):
os.mkdir(outdir)
fullname = os.path.join(outdir, outname)
output = pd.DataFrame(test_ids)
output = output.rename(columns={0: 'node_id'})
output['ExtendedCaseGraphID'] = test_pred
output = output.set_index('node_id')
output.to_csv(fullname)
return output