Expand description of the PersistentDataset usecase.
@@ -105,6 +105,11 @@ randomized transform in the transform chain. Enabling this feature could
potentially give 10x training speedups.
![image](../images/cache_dataset.png)
+A PersistentDataset is similar to the CacheIO, where the intermediate cache
+values are persisted to disk storage for rapid retrieval between experimental
+runs (as is the case when tuning hyper parameters), or when the entire data set
+size exceeds available memory.
+
## Losses
There are domain-specific loss functions in the medical imaging research which
are not typically used in the generic computer vision tasks. As an important
