lightning/pytorch_lightning/metrics/__init__.py

from pytorch_lightning.metrics.metric import Metric

from pytorch_lightning.metrics.classification import (
    Accuracy,
    Precision,
    Recall,
    Fbeta
)

from pytorch_lightning.metrics.regression import (
    MeanSquaredError,
    MeanAbsoluteError,
    MeanSquaredLogError,
    ExplainedVariance,
)