description: Just your regular densely-connected NN layer.
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Just your regular densely-connected NN layer.
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
)
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
).
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 1 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).
>>> # 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)
Arguments | |
---|---|
units
|
Positive integer, dimensionality of the output space. |
activation
|
Activation function to use.
If you don't specify anything, no activation is applied
(ie. "linear" activation: a(x) = x ).
|
use_bias
|
Boolean, whether the layer uses a bias vector. |
kernel_initializer
|
Initializer for the kernel weights matrix.
|
bias_initializer
|
Initializer for the bias vector. |
kernel_regularizer
|
Regularizer function applied to
the kernel weights matrix.
|
bias_regularizer
|
Regularizer function applied to the bias vector. |
activity_regularizer
|
Regularizer function applied to the output of the layer (its "activation"). |
kernel_constraint
|
Constraint function applied to
the kernel weights matrix.
|
bias_constraint
|
Constraint function applied to the bias vector. |
N-D tensor with shape: (batch_size, ..., input_dim)
.
The most common situation would be
a 2D input with shape (batch_size, input_dim)
.
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)
.