Source code for

import re

import torch
from .data import Data

[docs]class Batch(Data): r"""A plain old python object modeling a batch of graphs as one big (dicconnected) graph. With :class:`` being the base class, all its methods can also be used here. In addition, single graphs can be reconstructed via the assignment vector :obj:`batch`, which maps each node to its respective graph identifier. """ def __init__(self, batch=None, **kwargs): super(Batch, self).__init__(**kwargs) self.batch = batch self.__data_class__ = Data self.__slices__ = None
[docs] @staticmethod def from_data_list(data_list, follow_batch=[]): r"""Constructs a batch object from a python list holding :class:`` objects. The assignment vector :obj:`batch` is created on the fly. Additionally, creates assignment batch vectors for each key in :obj:`follow_batch`.""" keys = [set(data.keys) for data in data_list] keys = list(set.union(*keys)) assert "batch" not in keys batch = Batch() batch.__data_class__ = data_list[0].__class__ batch.__slices__ = {key: [0] for key in keys} for key in keys: batch[key] = [] for key in follow_batch: batch["{}_batch".format(key)] = [] cumsum = {key: 0 for key in keys} batch.batch = [] for i, data in enumerate(data_list): for key in data.keys: item = data[key] if torch.is_tensor(item) and item.dtype != torch.bool: item = item + cumsum[key] if torch.is_tensor(item): size = item.size(data.cat_dim(key, data[key])) else: size = 1 batch.__slices__[key].append(size + batch.__slices__[key][-1]) cumsum[key] = cumsum[key] + data.__inc__(key, item) batch[key].append(item) if key in follow_batch: item = torch.full((size,), i, dtype=torch.long) batch["{}_batch".format(key)].append(item) num_nodes = data.num_nodes if num_nodes is not None: item = torch.full((num_nodes,), i, dtype=torch.long) batch.batch.append(item) if num_nodes is None: batch.batch = None for key in batch.keys: item = batch[key][0] if torch.is_tensor(item): batch[key] =[key], dim=data_list[0].cat_dim(key, item)) elif isinstance(item, int) or isinstance(item, float): batch[key] = torch.tensor(batch[key]) return batch.contiguous()
[docs] def cumsum(self, key, item): r"""If :obj:`True`, the attribute :obj:`key` with content :obj:`item` should be added up cumulatively before concatenated together. .. note:: This method is for internal use only, and should only be overridden if the batch concatenation process is corrupted for a specific data attribute. """ return bool("(index|face)", key))
[docs] def to_data_list(self): r"""Reconstructs the list of :class:`` objects from the batch object. The batch object must have been created via :meth:`from_data_list` in order to be able reconstruct the initial objects.""" if self.__slices__ is None: raise RuntimeError( ( "Cannot reconstruct data list from batch because the batch " "object was not created using Batch.from_data_list()" ) ) keys = [key for key in self.keys if key[-5:] != "batch"] cumsum = {key: 0 for key in keys} data_list = [] for i in range(len(self.__slices__[keys[0]]) - 1): data = self.__data_class__() for key in keys: if torch.is_tensor(self[key]): data[key] = self[key].narrow( data.cat_dim(key, self[key]), self.__slices__[key][i], self.__slices__[key][i + 1] - self.__slices__[key][i], ) if self[key].dtype != torch.bool: data[key] = data[key] - cumsum[key] else: data[key] = self[key][ self.__slices__[key][i] : self.__slices__[key][i + 1] ] cumsum[key] = cumsum[key] + data.__inc__(key, data[key]) data_list.append(data) return data_list
@property def num_graphs(self): """Returns the number of graphs in the batch.""" return self.batch[-1].item() + 1