import torch.nn.functional as F
import torch.nn as nn
from . import BaseTask, register_task
from ..dataset import build_dataset
from ..utils import Evaluator
[docs]@register_task("node_classification")
class NodeClassification(BaseTask):
r"""
Node classification tasks.
Attributes
-----------
dataset : NodeClassificationDataset
Task-related dataset
evaluator : Evaluator
offer evaluation metric
Methods
---------
get_graph :
return a graph
get_loss_fn :
return a loss function
"""
def __init__(self, args):
super(NodeClassification, self).__init__()
self.logger = args.logger
self.dataset = build_dataset(args.dataset, 'node_classification', logger=self.logger)
# self.evaluator = Evaluator()
self.logger = args.logger
if hasattr(args, 'validation'):
self.train_idx, self.val_idx, self.test_idx = self.dataset.get_split(args.validation)
else:
self.train_idx, self.val_idx, self.test_idx = self.dataset.get_split()
self.evaluator = Evaluator(args.seed)
self.labels = self.dataset.get_labels()
self.multi_label = self.dataset.multi_label
if hasattr(args, 'evaluation_metric'):
self.evaluation_metric = args.evaluation_metric
else:
if args.dataset in ['aifb', 'mutag', 'bgs', 'am']:
self.evaluation_metric = 'acc'
else:
self.evaluation_metric = 'f1'
def get_graph(self):
return self.dataset.g
def get_loss_fn(self):
if self.multi_label:
return nn.BCEWithLogitsLoss()
return F.cross_entropy
def get_evaluator(self, name):
if name == 'acc':
return self.evaluator.cal_acc
elif name == 'f1_lr':
return self.evaluator.nc_with_LR
elif name == 'f1':
return self.evaluator.f1_node_classification
def evaluate(self, logits, mode='test', info=True):
if mode == 'test':
mask = self.test_idx
elif mode == 'valid':
mask = self.val_idx
elif mode == 'train':
mask = self.train_idx
if self.multi_label:
pred = (logits[mask].cpu().numpy() > 0).astype(int)
else:
pred = logits[mask].argmax(dim=1).to('cpu')
if self.evaluation_metric == 'acc':
acc = self.evaluator.cal_acc(self.labels[mask], pred)
return dict(Accuracy=acc)
elif self.evaluation_metric == 'acc-ogbn-mag':
from ogb.nodeproppred import Evaluator
evaluator = Evaluator(name='ogbn-mag')
logits = logits.unsqueeze(dim=1)
input_dict = {"y_true": logits, "y_pred": self.labels[self.test_idx]}
result_dict = evaluator.eval(input_dict)
return result_dict
elif self.evaluation_metric == 'f1':
f1_dict = self.evaluator.f1_node_classification(self.labels[mask], pred)
return f1_dict
else:
raise ValueError('The evaluation metric is not supported!')
def downstream_evaluate(self, logits, evaluation_metric):
if evaluation_metric == 'f1_lr':
micro_f1, macro_f1 = self.evaluator.nc_with_LR(logits, self.labels, self.train_idx, self.test_idx)
return dict(Macro_f1=macro_f1, Mirco_f1=micro_f1)
def get_split(self):
return self.train_idx, self.val_idx, self.test_idx
def get_labels(self):
return self.labels