当我搜索 mnist.train.next_batch() 时,我发现了这个 https://github.com/tensorflow/tensorflow/blob/master/tensorflow/contrib/learn/python/learn/datasets/mnist.py
在此代码中
def next_batch(self, batch_size, fake_data=False, shuffle=True):
"""Return the next `batch_size` examples from this data set."""
if fake_data:
fake_image = [1] * 784
if self.one_hot:
fake_label = [1] + [0] * 9
else:
fake_label = 0
return [fake_image for _ in xrange(batch_size)], [
fake_label for _ in xrange(batch_size)
]
start = self._index_in_epoch
# Shuffle for the first epoch
if self._epochs_completed == 0 and start == 0 and shuffle:
perm0 = numpy.arange(self._num_examples)
numpy.random.shuffle(perm0)
self._images = self.images[perm0]
self._labels = self.labels[perm0]
# Go to the next epoch
if start + batch_size > self._num_examples:
# Finished epoch
self._epochs_completed += 1
# Get the rest examples in this epoch
rest_num_examples = self._num_examples - start
images_rest_part = self._images[start:self._num_examples]
labels_rest_part = self._labels[start:self._num_examples]
# Shuffle the data
if shuffle:
perm = numpy.arange(self._num_examples)
numpy.random.shuffle(perm)
self._images = self.images[perm]
self._labels = self.labels[perm]
# Start next epoch
start = 0
self._index_in_epoch = batch_size - rest_num_examples
end = self._index_in_epoch
images_new_part = self._images[start:end]
labels_new_part = self._labels[start:end]
return numpy.concatenate((images_rest_part, images_new_part), axis=0) , numpy.concatenate((labels_rest_part, labels_new_part), axis=0)
else:
self._index_in_epoch += batch_size
end = self._index_in_epoch
return self._images[start:end], self._labels[start:end]
我知道 mnist.train.next_batch(batch_size=100) 意味着它从 MNIST 数据集中随机选取 100 个数据。现在,这是我的问题
- shuffle=true 是什么意思?
- 如果我设置 next_batch(batch_size=100,fake_data=False, shuffle=False) 那么它会依次从 MNIST 数据集的开头到结尾选取 100 个数据?不是随机的吗?
最佳答案
Re 1,当shuffle=True
时,数据中示例的顺序是随机的。 Re 2,是的,它应该尊重示例在 numpy 数组中的任何顺序。
关于python - Tensorflow - 关于 mnist.train.next_batch(),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42896605/