那些Keras和Pytorch片段等效吗?

发布于 2025-02-11 18:41:28 字数 1373 浏览 1 评论 0原文

我想知道我是否成功地将Pytorch的以下定义转换为Keras?

在Pytorch中,定义了以下多层感知:

from torch import nn
hidden = 128
def mlp(size_in, size_out, act=nn.ReLU):
    return nn.Sequential(
        nn.Linear(size_in, hidden),
        act(),
        nn.Linear(hidden, hidden),
        act(),
        nn.Linear(hidden, hidden),
        act(),
        nn.Linear(hidden, size_out),
    )

我的翻译是

from tensorflow import keras

from keras import layers

hidden = 128

def mlp(size_in, size_out, act=keras.layers.ReLU):
    return keras.Sequential(
        [
            layers.Dense(hidden, activation=None, name="layer1", input_shape=(size_in, 1)),
            act(),
            layers.Dense(hidden, activation=None, name="layer2", input_shape=(hidden, 1)),
            act(),
            layers.Dense(hidden, activation=None, name="layer3", input_shape=(hidden, 1)),
            act(),
            layers.Dense(size_out, activation=None, name="layer4", input_shape=(hidden, 1))
        ])

我对输入/输出参数特别困惑,因为这似乎是Tensorflow和Pytorch不同的地方。

来自 documentation> documentation

当传递流行的Kwarg Input_shape时,Keras将创建一个 输入层要在当前层之前插入。这可以对待 等效于明确定义输入器。

所以,我做对了吗?

I am wondering if I succeeded in translating the following definition in PyTorch to Keras?

In PyTorch, the following multi-layer perceptron was defined:

from torch import nn
hidden = 128
def mlp(size_in, size_out, act=nn.ReLU):
    return nn.Sequential(
        nn.Linear(size_in, hidden),
        act(),
        nn.Linear(hidden, hidden),
        act(),
        nn.Linear(hidden, hidden),
        act(),
        nn.Linear(hidden, size_out),
    )

My translation is

from tensorflow import keras

from keras import layers

hidden = 128

def mlp(size_in, size_out, act=keras.layers.ReLU):
    return keras.Sequential(
        [
            layers.Dense(hidden, activation=None, name="layer1", input_shape=(size_in, 1)),
            act(),
            layers.Dense(hidden, activation=None, name="layer2", input_shape=(hidden, 1)),
            act(),
            layers.Dense(hidden, activation=None, name="layer3", input_shape=(hidden, 1)),
            act(),
            layers.Dense(size_out, activation=None, name="layer4", input_shape=(hidden, 1))
        ])

I am particularly confused about the input/output arguments, because that seems to be where tensorflow and PyTorch differ.

From the documentation:

When a popular kwarg input_shape is passed, then keras will create an
input layer to insert before the current layer. This can be treated
equivalent to explicitly defining an InputLayer.

So, did I get it right?

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评论(1

数理化全能战士 2025-02-18 18:41:28

在keras中,您可以为第一层提供input_shape,或者使用 tf.keras.layers.input 图层。如果您不提供这些详细信息中的任何一个,则在您第一次调用fiteval预测 时构建模型,或第一个时间您在某些输入数据上调用模型。因此,如果您不提供输入形状,则实际上将被推断出来。请参阅 docs> docs ,有关更多详细信息。 Pytorch通常在运行时侵入输入形状。

def keras_mlp(size_in, size_out, act=layers.ReLU):
    return keras.Sequential([layers.Input(shape=(size_in,)),
                             layers.Dense(hidden, name='layer1'),
                             act(),
                             layers.Dense(hidden, name='layer2'),
                             act(),
                             layers.Dense(hidden, name='layer3'),
                             act(),
                             layers.Dense(size_out, name='layer4')])

def pytorch_mlp(size_in, size_out, act=nn.ReLU):
    return nn.Sequential(nn.Linear(size_in, hidden),
                         act(),
                         nn.Linear(hidden, hidden),
                         act(),
                         nn.Linear(hidden, hidden),
                         act(),
                         nn.Linear(hidden, size_out))

您可以比较他们的摘要。

  • keras:

     >>> keras_mlp(10,5).summary()
    型号:“ sequention_2”
    __________________________________________________________________________
     图层(类型)输出形状参数#   
    =============================================== ===============
     Layer1(密集)(无,128)1408      
    
     re_lu_6(relu)(无,128)0         
    
     Layer2(密集)(无,128)16512     
    
     re_lu_7(relu)(无,128)0         
    
     层3(密集)(无,128)16512     
    
     re_lu_8(relu)(无,128)0         
    
     层4(密集)(无,5)645       
    
    =============================================== ===============
    总参数:35,077
    可训练的参数:35,077
    不可训练的参数:0
    __________________________________________________________________________
     
  • for pytorch:

     >>>摘要(pytorch_mlp(10,5),(1,10))
    =============================================== ==========================
    图层(类型:depth-idx)输出形状参数#
    =============================================== ==========================
    顺序[1,5]  - 
    ├─固态:1-1 [1,128] 1,408
    Relu:1-2 [1,128]  - 
    ├─固态:1-3 [1,128] 16,512
    Relu:1-4 [1,128]  - 
    ├─固态:1-5 [1,128] 16,512
    Relu:1-6 [1,128]  - 
    ├─固态:1-7 [1,5] 645
    =============================================== ==========================
    总参数:35,077
    可训练的参数:35,077
    不可训练的参数:0
    总多攻(M):0.04
    =============================================== ==========================
    输入尺寸(MB):0.00
    向前/向后的大小(MB):0.00
    参数大小(MB):0.14
    估计总尺寸(MB):0.14
    =============================================== ==========================
     

In Keras, you can provide an input_shape for the first layer or alternatively use the tf.keras.layers.Input layer. If you do not provide either of these details, the model gets built the first time you call fit, eval, or predict, or the first time you call the model on some input data. So the input shape will actually be inferred if you do not provide it. See the docs for more details. PyTorch generally infers the input shape at runtime.

def keras_mlp(size_in, size_out, act=layers.ReLU):
    return keras.Sequential([layers.Input(shape=(size_in,)),
                             layers.Dense(hidden, name='layer1'),
                             act(),
                             layers.Dense(hidden, name='layer2'),
                             act(),
                             layers.Dense(hidden, name='layer3'),
                             act(),
                             layers.Dense(size_out, name='layer4')])

def pytorch_mlp(size_in, size_out, act=nn.ReLU):
    return nn.Sequential(nn.Linear(size_in, hidden),
                         act(),
                         nn.Linear(hidden, hidden),
                         act(),
                         nn.Linear(hidden, hidden),
                         act(),
                         nn.Linear(hidden, size_out))

You can compare their summary.

  • For Keras:

    >>> keras_mlp(10, 5).summary()
    Model: "sequential_2"
    _________________________________________________________________
     Layer (type)                Output Shape              Param #   
    =================================================================
     layer1 (Dense)              (None, 128)               1408      
    
     re_lu_6 (ReLU)              (None, 128)               0         
    
     layer2 (Dense)              (None, 128)               16512     
    
     re_lu_7 (ReLU)              (None, 128)               0         
    
     layer3 (Dense)              (None, 128)               16512     
    
     re_lu_8 (ReLU)              (None, 128)               0         
    
     layer4 (Dense)              (None, 5)                 645       
    
    =================================================================
    Total params: 35,077
    Trainable params: 35,077
    Non-trainable params: 0
    _________________________________________________________________
    
  • For PyTorch:

    >>> summary(pytorch_mlp(10, 5), (1,10))
    ============================================================================
    Layer (type:depth-idx)                   Output Shape              Param #
    ============================================================================
    Sequential                               [1, 5]                    --
    ├─Linear: 1-1                            [1, 128]                  1,408
    ├─ReLU: 1-2                              [1, 128]                  --
    ├─Linear: 1-3                            [1, 128]                  16,512
    ├─ReLU: 1-4                              [1, 128]                  --
    ├─Linear: 1-5                            [1, 128]                  16,512
    ├─ReLU: 1-6                              [1, 128]                  --
    ├─Linear: 1-7                            [1, 5]                    645
    ============================================================================
    Total params: 35,077
    Trainable params: 35,077
    Non-trainable params: 0
    Total mult-adds (M): 0.04
    ============================================================================
    Input size (MB): 0.00
    Forward/backward pass size (MB): 0.00
    Params size (MB): 0.14
    Estimated Total Size (MB): 0.14
    ============================================================================
    
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