Source code for

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# coding: utf-8
"""Contrib data iterators for common data formats."""
from __future__ import absolute_import
from import DataIter, DataDesc
from .. import ndarray as nd

[docs]class DataLoaderIter(DataIter): """Returns an iterator for ```` so gluon dataloader can be used in symbolic module. Parameters ---------- loader : Gluon dataloader instance data_name : str, optional The data name. label_name : str, optional The label name. dtype : str, optional The dtype specifier, can be float32 or float16 Examples -------- >>> import mxnet as mx >>> from import MNIST >>> from import DataLoader >>> train_dataset = MNIST(train=True) >>> train_data =, 32, shuffle=True, num_workers=4) >>> dataiter = >>> for batch in dataiter: ...[0].shape ... (32L, 28L, 28L, 1L) """ def __init__(self, loader, data_name='data', label_name='softmax_label', dtype='float32'): super(DataLoaderIter, self).__init__() self._loader = loader self._iter = iter(self._loader) data, label = next(self._iter) self.batch_size = data.shape[0] self.dtype = dtype self.provide_data = [DataDesc(data_name, data.shape, dtype)] self.provide_label = [DataDesc(label_name, label.shape, dtype)] self._current_batch = None self.reset()
[docs] def reset(self): self._iter = iter(self._loader)
[docs] def iter_next(self): try: self._current_batch = next(self._iter) except StopIteration: self._current_batch = None return self._current_batch is not None
[docs] def getdata(self): if self.getpad(): dshape = self._current_batch[0].shape ret = nd.empty(shape=([self.batch_size] + list(dshape[1:]))) ret[:dshape[0]] = self._current_batch[0].astype(self.dtype) return [ret] return [self._current_batch[0].astype(self.dtype)]
[docs] def getlabel(self): if self.getpad(): lshape = self._current_batch[1].shape ret = nd.empty(shape=([self.batch_size] + list(lshape[1:]))) ret[:lshape[0]] = self._current_batch[1].astype(self.dtype) return [ret] return [self._current_batch[1].astype(self.dtype)]
[docs] def getpad(self): return self.batch_size - self._current_batch[0].shape[0]
[docs] def getindex(self): return None