refact dataset, dataloader and datamodule

This commit is contained in:
FilippoOlivo
2025-11-12 14:32:56 +01:00
parent f07e59b69b
commit 99e2f07cf7
4 changed files with 375 additions and 460 deletions

245
pina/data/dataloader.py Normal file
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from torch.utils.data import DataLoader
from functools import partial
from torch.utils.data.distributed import DistributedSampler
from torch.utils.data.sampler import SequentialSampler
import torch
class DummyDataloader:
def __init__(self, dataset):
"""
Prepare a dataloader object that returns the entire dataset in a single
batch. Depending on the number of GPUs, the dataset is managed
as follows:
- **Distributed Environment** (multiple GPUs): Divides dataset across
processes using the rank and world size. Fetches only portion of
data corresponding to the current process.
- **Non-Distributed Environment** (single GPU): Fetches the entire
dataset.
:param PinaDataset dataset: The dataset object to be processed.
.. note::
This dataloader is used when the batch size is ``None``.
"""
print("Using DummyDataloader")
if (
torch.distributed.is_available()
and torch.distributed.is_initialized()
):
rank = torch.distributed.get_rank()
world_size = torch.distributed.get_world_size()
if len(dataset) < world_size:
raise RuntimeError(
"Dimension of the dataset smaller than world size."
" Increase the size of the partition or use a single GPU"
)
idx, i = [], rank
while i < len(dataset):
idx.append(i)
i += world_size
else:
idx = list(range(len(dataset)))
self.dataset = dataset._getitem_from_list(idx)
def __iter__(self):
return self
def __len__(self):
return 1
def __next__(self):
return self.dataset
class PinaSampler:
"""
This class is used to create the sampler instance based on the shuffle
parameter and the environment in which the code is running.
"""
def __new__(cls, dataset, shuffle=True):
"""
Instantiate and initialize the sampler.
:param PinaDataset dataset: The dataset from which to sample.
:return: The sampler instance.
:rtype: :class:`torch.utils.data.Sampler`
"""
if (
torch.distributed.is_available()
and torch.distributed.is_initialized()
):
sampler = DistributedSampler(dataset, shuffle=shuffle)
else:
if shuffle:
sampler = torch.utils.data.RandomSampler(dataset)
else:
sampler = SequentialSampler(dataset)
return sampler
def _collect_items(batch):
"""
Helper function to collect items from a batch of graph data samples.
:param batch: List of graph data samples.
"""
to_return = {name: [] for name in batch[0].keys()}
for sample in batch:
for k, v in sample.items():
to_return[k].append(v)
return to_return
def collate_fn_custom(batch, dataset):
"""
Override the default collate function to handle datasets without automatic batching.
:param batch: List of indices from the dataset.
:param dataset: The PinaDataset instance (must be provided).
"""
return dataset._getitem_from_list(batch)
def collate_fn_default(batch, stack_fn):
"""
Default collate function that simply returns the batch as is.
:param batch: List of data samples.
"""
print("Using default collate function")
to_return = _collect_items(batch)
return {k: stack_fn[k](v) for k, v in to_return.items()}
class PinaDataLoader:
"""
Custom DataLoader for PinaDataset.
"""
def __init__(
self,
dataset_dict,
batch_size,
shuffle=False,
num_workers=0,
collate_fn=None,
common_batch_size=True,
):
self.dataset_dict = dataset_dict
self.batch_size = batch_size
self.shuffle = shuffle
self.num_workers = num_workers
self.collate_fn = collate_fn
print(batch_size)
if batch_size is None:
batch_size_per_dataset = {
split: None for split in dataset_dict.keys()
}
else:
if common_batch_size:
batch_size_per_dataset = {
split: batch_size for split in dataset_dict.keys()
}
else:
batch_size_per_dataset = self._compute_batch_size()
self.dataloaders = {
split: self._create_dataloader(
dataset, batch_size_per_dataset[split]
)
for split, dataset in dataset_dict.items()
}
def _compute_batch_size(self):
"""
Compute an appropriate batch size for the given dataset.
"""
elements_per_dataset = {
dataset_name: len(dataset)
for dataset_name, dataset in self.dataset_dict.items()
}
total_elements = sum(el for el in elements_per_dataset.values())
portion_per_dataset = {
name: el / total_elements
for name, el in elements_per_dataset.items()
}
batch_size_per_dataset = {
name: max(1, int(portion * self.batch_size))
for name, portion in portion_per_dataset.items()
}
tot_el_per_batch = sum(el for el in batch_size_per_dataset.values())
if self.batch_size > tot_el_per_batch:
difference = self.batch_size - tot_el_per_batch
while difference > 0:
for k, v in batch_size_per_dataset.items():
if difference == 0:
break
if v > 1:
batch_size_per_dataset[k] += 1
difference -= 1
if self.batch_size < tot_el_per_batch:
difference = tot_el_per_batch - self.batch_size
while difference > 0:
for k, v in batch_size_per_dataset.items():
if difference == 0:
break
if v > 1:
batch_size_per_dataset[k] -= 1
difference -= 1
return batch_size_per_dataset
def _create_dataloader(self, dataset, batch_size):
print(batch_size)
if batch_size is None:
return DummyDataloader(dataset)
if not dataset.automatic_batching:
collate_fn = partial(collate_fn_custom, dataset=dataset)
else:
collate_fn = partial(collate_fn_default, stack_fn=dataset.stack_fn)
return DataLoader(
dataset,
batch_size=batch_size,
num_workers=self.num_workers,
collate_fn=collate_fn,
sampler=PinaSampler(dataset, shuffle=self.shuffle),
)
def __len__(self):
return max(len(dl) for dl in self.dataloaders.values())
def __iter__(self):
"""
Restituisce un iteratore che produce dizionari di batch.
Itera per un numero di passi pari al dataloader più lungo (come da __len__)
e fa ricominciare i dataloader più corti quando si esauriscono.
"""
# 1. Crea un iteratore per ogni dataloader
iterators = {split: iter(dl) for split, dl in self.dataloaders.items()}
# 2. Itera per il numero di batch del dataloader più lungo
for _ in range(len(self)):
# 3. Prepara il dizionario di batch per questo step
batch_dict = {}
# 4. Ottieni il prossimo batch da ogni iteratore
for split, it in iterators.items():
try:
batch = next(it)
except StopIteration:
# 5. Se un iteratore è esaurito, resettalo e prendi il primo batch
new_it = iter(self.dataloaders[split])
iterators[split] = new_it # Salva il nuovo iteratore
batch = next(new_it)
batch_dict[split] = batch
# 6. Restituisci il dizionario di batch
yield batch_dict