Tensorflow - ValueError：无法将 NumPy 数组转换为 Tensor（不支持的对象类型 float）

Question

上一个问题的延续： Tensorflow - TypeError: ‘int’ object is not iterable

我的训练数据是一个列表列表，每个列表由 1000 个浮点数组成。例如， x_train[0] =

 [0.0, 0.0, 0.1, 0.25, 0.5, ...]

这是我的模型：

 model = Sequential()

model.add(LSTM(128, activation='relu',
               input_shape=(1000, 1), return_sequences=True))
model.add(Dropout(0.2))
model.add(LSTM(128, activation='relu'))
model.add(Dropout(0.2))
model.add(Dense(32, activation='relu'))
model.add(Dropout(0.2))
model.add(Dense(1, activation='sigmoid'))

opt = tf.keras.optimizers.Adam(lr=1e-3, decay=1e-5)

model.compile(optimizer='rmsprop',
              loss='binary_crossentropy',
              metrics=['accuracy'])

model.fit(x_train, y_train, epochs=3, validation_data=(x_test, y_test))

这是我得到的错误：

 Traceback (most recent call last):
      File "C:\Users\bencu\Desktop\ProjectFiles\Code\Program.py", line 88, in FitModel
        model.fit(x_train, y_train, epochs=3, validation_data=(x_test, y_test))
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training.py", line 728, in fit
        use_multiprocessing=use_multiprocessing)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py", line 224, in fit
        distribution_strategy=strategy)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py", line 547, in _process_training_inputs
        use_multiprocessing=use_multiprocessing)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\training_v2.py", line 606, in _process_inputs
        use_multiprocessing=use_multiprocessing)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\data_adapter.py", line 479, in __init__
        batch_size=batch_size, shuffle=shuffle, **kwargs)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\keras\engine\data_adapter.py", line 321, in __init__
        dataset_ops.DatasetV2.from_tensors(inputs).repeat()
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\data\ops\dataset_ops.py", line 414, in from_tensors
        return TensorDataset(tensors)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\data\ops\dataset_ops.py", line 2335, in __init__
        element = structure.normalize_element(element)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\data\util\structure.py", line 111, in normalize_element
        ops.convert_to_tensor(t, name="component_%d" % i))
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\ops.py", line 1184, in convert_to_tensor
        return convert_to_tensor_v2(value, dtype, preferred_dtype, name)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\ops.py", line 1242, in convert_to_tensor_v2
        as_ref=False)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\ops.py", line 1296, in internal_convert_to_tensor
        ret = conversion_func(value, dtype=dtype, name=name, as_ref=as_ref)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\tensor_conversion_registry.py", line 52, in _default_conversion_function
        return constant_op.constant(value, dtype, name=name)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\constant_op.py", line 227, in constant
        allow_broadcast=True)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\constant_op.py", line 235, in _constant_impl
        t = convert_to_eager_tensor(value, ctx, dtype)
      File "C:\Users\bencu\AppData\Local\Programs\Python\Python37\lib\site-packages\tensorflow_core\python\framework\constant_op.py", line 96, in convert_to_eager_tensor
        return ops.EagerTensor(value, ctx.device_name, dtype)
    ValueError: Failed to convert a NumPy array to a Tensor (Unsupported object type float).

我自己尝试用谷歌搜索错误，我发现了一些关于使用 tf.convert_to_tensor 函数的信息。我尝试通过它传递我的训练和测试列表，但该函数不会接受它们。

原文由 SuperHanz98 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

TL;DR 几个可能的错误，大多数已修复 x = np.asarray(x).astype('float32') 。

其他可能是错误的数据预处理；确保所有内容的 _格式正确_（分类、nans、字符串等）。下面显示了模型的预期：

 [print(i.shape, i.dtype) for i in model.inputs]
[print(o.shape, o.dtype) for o in model.outputs]
[print(l.name, l.input_shape, l.dtype) for l in model.layers]

---

问题的根源在于使用 列表 作为输入，而不是 Numpy 数组； Keras/TF 不支持前者。一个简单的转换是： x_array = np.asarray(x_list) 。

下一步是确保以预期格式提供数据；对于 LSTM，这将是一个 3D 张量，其尺寸为 (batch_size, timesteps, features) 或等效地， (num_samples, timesteps, channels) 。最后，作为调试专业提示， _打印数据的所有形状_。完成上述所有内容的代码如下：

 Sequences = np.asarray(Sequences)
Targets   = np.asarray(Targets)
show_shapes()

Sequences = np.expand_dims(Sequences, -1)
Targets   = np.expand_dims(Targets, -1)
show_shapes()

 # OUTPUTS
Expected: (num_samples, timesteps, channels)
Sequences: (200, 1000)
Targets:   (200,)

Expected: (num_samples, timesteps, channels)
Sequences: (200, 1000, 1)
Targets:   (200, 1)

---

作为奖励提示，我注意到您正在通过 main() 运行，因此您的 IDE 可能缺少类似 Jupyter 的基于单元格的执行；我强烈推荐 Spyder IDE 。就像在下面添加 # In[] 并按下 Ctrl + Enter 一样简单：

---

使用的功能：

 def show_shapes(): # can make yours to take inputs; this'll use local variable values
    print("Expected: (num_samples, timesteps, channels)")
    print("Sequences: {}".format(Sequences.shape))
    print("Targets:   {}".format(Targets.shape))

原文由 OverLordGoldDragon 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

在尝试以上所有操作均未成功后，我发现我的问题是我的数据中的一列具有 boolean 值。将所有内容转换成 np.float32 解决了这个问题！

 import numpy as np

X = np.asarray(X).astype(np.float32)

原文由 Vasco Cansado Carvalho 发布，翻译遵循 CC BY-SA 4.0 许可协议