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  • TensorFlow
  • API
  • TensorFlow Core v2.8.0
  • Python

tf.keras.layers.Dense

TensorFlow 1 version
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Just your regular densely-connected NN layer.

Inherits From: Layer, Module

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tf.compat.v1.keras.layers.Dense

tf.keras.layers.Dense[ units, activation=None, use_bias=True, kernel_initializer='glorot_uniform', bias_initializer='zeros', kernel_regularizer=None, bias_regularizer=None, activity_regularizer=None, kernel_constraint=None, bias_constraint=None, **kwargs ]

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Dense implements the operation: output = activation[dot[input, kernel] + bias] where activation is the element-wise activation function passed as the activation argument, kernel is a weights matrix created by the layer, and bias is a bias vector created by the layer [only applicable if use_bias is True]. These are all attributes of Dense.

Note: If the input to the layer has a rank greater than 2, then Dense computes the dot product between the inputs and the kernel along the last axis of the inputs and axis 0 of the kernel [using tf.tensordot]. For example, if input has dimensions [batch_size, d0, d1], then we create a kernel with shape [d1, units], and the kernel operates along axis 2 of the input, on every sub-tensor of shape [1, 1, d1] [there are batch_size * d0 such sub-tensors]. The output in this case will have shape [batch_size, d0, units].

Besides, layer attributes cannot be modified after the layer has been called once [except the trainable attribute]. 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.

Example:

# Create a `Sequential` model and add a Dense layer as the first layer. model = tf.keras.models.Sequential[] model.add[tf.keras.Input[shape=[16,]]] model.add[tf.keras.layers.Dense[32, activation='relu']] # Now the model will take as input arrays of shape [None, 16] # and output arrays of shape [None, 32]. # Note that after the first layer, you don't need to specify # the size of the input anymore: model.add[tf.keras.layers.Dense[32]] model.output_shape [None, 32]

Args

unitsPositive integer, dimensionality of the output space.
activationActivation function to use. If you don't specify anything, no activation is applied [ie. "linear" activation: a[x] = x].
use_biasBoolean, whether the layer uses a bias vector.
kernel_initializerInitializer for the kernel weights matrix.
bias_initializerInitializer for the bias vector.
kernel_regularizerRegularizer function applied to the kernel weights matrix.
bias_regularizerRegularizer function applied to the bias vector.
activity_regularizerRegularizer function applied to the output of the layer [its "activation"].
kernel_constraintConstraint function applied to the kernel weights matrix.
bias_constraintConstraint function applied to the bias vector.

Input shape:

N-D tensor with shape: [batch_size, ..., input_dim]. The most common situation would be a 2D input with shape [batch_size, input_dim].

Output shape:

N-D tensor with shape: [batch_size, ..., units]. For instance, for a 2D input with shape [batch_size, input_dim], the output would have shape [batch_size, units].

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