TypeError：预期为 float32，但得到了“str”类型的 auto。 TensorFlow 错误，告诉我如何解决？答案

【问题标题】：TypeError: Expected float32, but got auto of type 'str'. Tensorflow error , tell me how to fix it?TypeError：预期为 float32，但得到了“str”类型的 auto。 TensorFlow 错误，告诉我如何解决？
【发布时间】：2022-01-05 16:34:56
【问题描述】：

我得到 TypeError: Expected float32, but got auto of type 'str'. 在拟合顺序模型时出错。我检查了我的输入都是 numpy.ndarray。

type(xtrain),type(ytrain)
(numpy.ndarray, numpy.ndarray)

model = tf.keras.Sequential()

model.add(tf.keras.layers.Flatten(input_shape = (28,28)))
model.add(tf.keras.layers.Dense(32,activation='relu'))
model.add(tf.keras.layers.Dense(32,activation='relu'))
model.add(tf.keras.layers.Dense(10,activation=tf.keras.activations.softmax))

model.compile(loss = tf.keras.losses.SparseCategoricalCrossentropy,optimizer = 
    tf.keras.optimizers.Adam(learning_rate=.0001),metrics = ['accuracy'])

model.fit(x =xtrain,y = ytrain,epochs=100)

Epoch 1/100

TypeError Traceback（最近一次调用最后一次）在（） ----> 1 model.fit(x =xtrain,y = ytrain,epochs=100)

1 帧 /usr/local/lib/python3.7/dist-packages/tensorflow/python/framework/func_graph.py in autograph_handler(*args, **kwargs) 1127 例外为 e：# pylint:disable=broad-except 1128 如果有属性（例如，“ag_error_metadata”）： -> 1129 引发 e.ag_error_metadata.to_exception(e) 1130 其他：第1131章

TypeError：在用户代码中：

File "/usr/local/lib/python3.7/dist-packages/keras/engine/training.py", line 878, in train_function  *
    return step_function(self, iterator)
File "/usr/local/lib/python3.7/dist-packages/keras/engine/training.py", line 867, in step_function  **
    outputs = model.distribute_strategy.run(run_step, args=(data,))
File "/usr/local/lib/python3.7/dist-packages/keras/engine/training.py", line 860, in run_step  **
    outputs = model.train_step(data)
File "/usr/local/lib/python3.7/dist-packages/keras/engine/training.py", line 810, in train_step
    y, y_pred, sample_weight, regularization_losses=self.losses)
File "/usr/local/lib/python3.7/dist-packages/keras/engine/compile_utils.py", line 201, in __call__
    loss_value = loss_obj(y_t, y_p, sample_weight=sw)
File "/usr/local/lib/python3.7/dist-packages/keras/losses.py", line 141, in __call__
    losses = call_fn(y_true, y_pred)
File "/usr/local/lib/python3.7/dist-packages/keras/losses.py", line 245, in call  **
    return ag_fn(y_true, y_pred, **self._fn_kwargs)
File "/usr/local/lib/python3.7/dist-packages/keras/losses.py", line 752, in __init__  **
    from_logits=from_logits)
File "/usr/local/lib/python3.7/dist-packages/keras/losses.py", line 227, in __init__
    super().__init__(reduction=reduction, name=name)
File "/usr/local/lib/python3.7/dist-packages/keras/losses.py", line 88, in __init__
    losses_utils.ReductionV2.validate(reduction)
File "/usr/local/lib/python3.7/dist-packages/keras/utils/losses_utils.py", line 82, in validate
    if key not in cls.all():

TypeError: Expected float32, but got auto of type 'str'.

【问题讨论】：

标签： python tensorflow deep-learning typeerror tensorflow2.0

【解决方案1】：

错误可能在这部分代码中：

model.compile(loss = tf.keras.losses.SparseCategoricalCrossentropy,optimizer = tf.keras.optimizers.Adam(learning_rate=.0001),metrics = ['accuracy'])

尝试将损失参数从tf.keras.losses.SparseCategoricalCrossentropy 更改为tf.keras.losses.SparseCategoricalCrossentropy()。

为了清楚起见，两者之间的区别在于，tf.keras.losses.SparseCategoricalCrossentropy 你是不是类的实例，tf.keras.losses.SparseCategoricalCrossentropy() 你是。

【讨论】：