convolution1dLayer
Description
A 1-D convolutional layer applies sliding convolutional filters to 1-D input. The layer convolves the input by moving the filters along the input and computing the dot product of the weights and the input, then adding a bias term.
The dimension that the layer convolves over depends on the layer input:
For time series and vector sequence input (data with three dimensions corresponding to the channels, observations, and time steps), the layer convolves over the time dimension.
For 1-D image input (data with three dimensions corresponding to the spatial pixels, channels, and observations), the layer convolves over the spatial dimension.
For 1-D image sequence input (data with four dimensions corresponding to the spatial pixels, channels, observations, and time steps), the layer convolves over the spatial dimension.
Creation
Syntax
Description
creates a 1-D convolutional layer and sets the layer = convolution1dLayer(filterSize,numFilters)FilterSize and NumFilters properties.
sets optional properties using one or more name-value arguments.layer = convolution1dLayer(filterSize,numFilters,Name=Value)
Input Arguments
Width of the filters, specified as a positive integer.
This argument sets the FilterSize property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Number of filters, specified as a positive integer. This number determines the number of channels (feature maps) in the layer output.
This argument sets the NumFilters property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN, where Name is
the argument name and Value is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Example: convolution1dLayer(11,96,Padding=1) creates a 1-D
convolutional layer with 96 filters of size 11, and specifies padding of size 1
on the left and right of the layer input.
Step size for traversing the input, specified as a positive integer.
This argument sets the Stride property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Factor for dilated convolution (also known as atrous convolution), specified as a positive integer.
Use dilated convolutions to increase the receptive field (the area of the input that the layer can see) of the layer without increasing the number of parameters or computation.
The layer expands the filters by inserting zeros between each filter element. The dilation
factor determines the step size for sampling the input, or equivalently, the upsampling
factor of the filter. It corresponds to an effective filter size of (FilterSize –
1) .* DilationFactor + 1. For example, a 1-by-3 filter with a dilation factor
of 2 is equivalent to a 1-by-5 filter with zeros between the
elements.
This argument sets the DilationFactor property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Padding to apply to the input, specified as one of the following:
"same"— Apply padding such that the output size isceil(inputSize/stride), whereinputSizeis the length of the input. WhenStrideis1, the output is the same size as the input."causal"— Apply left padding to the input, equal to(FilterSize - 1) .* DilationFactor. WhenStrideis1, the output is the same size as the input.Nonnegative integer
sz— Add padding of sizeszto both ends of the input.Vector
[l r]of nonnegative integers — Add padding of sizelto the left andrto the right of the input.
Example: Padding=[2 1] adds padding of size 2 to
the left and size 1 to the right of the input.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | char | string
Value to pad data, specified as one of these values:
PaddingValue | Description | Example |
|---|---|---|
| Scalar | Pad with the specified scalar value. | |
"symmetric-include-edge" | Pad using mirrored values of the input, including the edge values. | |
"symmetric-exclude-edge" | Pad using mirrored values of the input, excluding the edge values. | |
"replicate" | Pad using repeated border elements of the input. |
This argument sets the PaddingValue property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | char | string
Number of input channels, specified as one of these values:
"auto"— Automatically determine the number of input channels at training time.Positive integer — Configure the layer for the specified number of input channels.
NumChannelsand the number of channels in the layer input data must match. For example, if the input is an RGB image, thenNumChannelsmust be 3. If the input is the output of a convolutional layer with 16 filters, thenNumChannelsmust be 16.
This argument sets the NumChannels property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | char | string
Function to initialize the weights, specified as one of the following:
"glorot"— Initialize the weights with the Glorot initializer [1] (also known as the Xavier initializer). The Glorot initializer independently samples from a normal distribution with a mean of zero and a variance of2/(numIn + numOut), wherenumIn = FilterSize*NumChannelsandnumOut = FilterSize*NumFilters."he"— Initialize the weights with the He initializer [2]. The He initializer samples from a normal distribution with a mean of zero and a variance of2/numIn, wherenumIn = FilterSize*NumChannels."narrow-normal"— Initialize the weights by independently sampling from a normal distribution with a mean of zero and a standard deviation of 0.01."zeros"— Initialize the weights with zeros."ones"— Initialize the weights with ones.Function handle — Initialize the weights with a custom function. If you specify a function handle, then the function syntax must be of the form
weights = func(sz), whereszis the size of the weights. For an example, see Specify Custom Weight Initialization Function.
The layer only initializes the weights when the Weights property is
empty.
This argument sets the WeightsInitializer property.
Data Types: char | string | function_handle
Function to initialize the biases, specified as one of these values:
"zeros"— Initialize the biases with zeros."ones"— Initialize the biases with ones."narrow-normal"— Initialize the biases by independently sampling from a normal distribution with a mean of zero and a standard deviation of 0.01.Function handle — Initialize the biases with a custom function. If you specify a function handle, then the function must have the form
bias = func(sz), whereszis the size of the biases.
The layer initializes the biases only when the Bias property is
empty.
This argument sets the BiasInitializer property.
Data Types: char | string | function_handle
Layer weights for the convolution operation, specified as a
FilterSize-by-NumChannels-by-NumFilters
numeric array or [].
The layer weights are learnable parameters. You can specify the initial value of the weights
directly using the Weights property of the layer. When
you train a network, if the Weights property of the layer
is nonempty, then the trainnet
function uses the Weights property as the initial value.
If the Weights property is empty, then the software uses
the initializer specified by the WeightsInitializer
property of the layer.
This argument sets the Weights property.
Data Types: single | double
Layer biases for the convolution operation, specified as a
1-by-NumFilters numeric array or [].
The layer biases are learnable parameters. When you train a neural network, if Bias is nonempty, then the trainnet
function uses the Bias property as the initial value. If
Bias is empty, then software uses the initializer
specified by the BiasInitializer property.
This argument sets the Bias property.
Data Types: single | double
Learning rate factor for the weights, specified as a nonnegative scalar.
The software multiplies this factor by the global learning rate to determine the learning rate for the weights in this layer. For example, if WeightLearnRateFactor is 2, then the learning rate for the weights in this layer is twice the current global learning rate. The software determines the global learning rate based on the settings you specify using the trainingOptions function.
This argument sets the WeightLearnRateFactor property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Learning rate factor for the biases, specified as a nonnegative scalar.
The software multiplies this factor by the global learning rate to determine the learning rate for the biases in this layer. For example, if BiasLearnRateFactor is 2, then the learning rate for the biases in the layer is twice the current global learning rate. The software determines the global learning rate based on the settings you specify using the trainingOptions function.
This argument sets the BiasLearnRateFactor property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
L2 regularization factor for the weights, specified as a nonnegative scalar.
The software multiplies this factor by the global L2 regularization factor to determine the L2 regularization for the weights in this layer. For example, if WeightL2Factor is 2, then the L2 regularization for the weights in this layer is twice the global L2 regularization factor. You can specify the global L2 regularization factor using the trainingOptions function.
This argument sets the WeightL2Factor
property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
L2 regularization factor for the biases, specified as a nonnegative scalar.
The software multiplies this factor by the global L2 regularization factor to determine the L2 regularization for the biases in this layer. For example, if BiasL2Factor is 2, then the L2 regularization for the biases in this layer is twice the global L2 regularization factor. The software determines the global L2 regularization factor based on the settings you specify using the trainingOptions function.
This argument sets the BiasL2Factor property.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Properties
1-D Convolution
This property is read-only after object creation. To set this property, use the corresponding
positional input argument when you create the Convolution1DLayer
object.
Width of the filters, specified as a positive integer.
Data Types: double
This property is read-only after object creation. To set this property, use the corresponding
positional input argument when you create the Convolution1DLayer
object.
Number of filters, specified as a positive integer. This number determines the number of channels (feature maps) in the layer output.
Data Types: double
Step size for traversing the input, specified as a positive integer.
The Convolution1DLayer object stores this property as double
type.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Factor for dilated convolution (also known as atrous convolution), specified as a positive integer.
Use dilated convolutions to increase the receptive field (the area of the input that the layer can see) of the layer without increasing the number of parameters or computation.
The layer expands the filters by inserting zeros between each filter element. The dilation
factor determines the step size for sampling the input, or equivalently, the upsampling
factor of the filter. It corresponds to an effective filter size of (FilterSize –
1) .* DilationFactor + 1. For example, a 1-by-3 filter with a dilation factor
of 2 is equivalent to a 1-by-5 filter with zeros between the
elements.
The Convolution1DLayer object stores this property as double
type.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Size of padding to apply to each side of the input, specified as a vector [l
r] of two nonnegative integers, where l is the padding
applied to the left and r is the padding applied to the right.
When you create a layer, use the Padding
name-value argument to specify the padding size.
The Convolution1DLayer object stores this property as double
type.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
This property is read-only after object creation. To set this
property, use the Padding name-value argument when you create the
Convolution1DLayer object.
Method to determine padding size, specified as one of the following:
'manual'– Pad using the integer or vector specified byPadding.'same'– Apply padding such that the output size isceil(inputSize/Stride), whereinputSizeis the length of the input. WhenStrideis1, the output is the same as the input.'causal'– Apply causal padding. Pad the left of the input with padding size(FilterSize - 1) .* DilationFactor.
Data Types: char
This property is read-only after object creation. To set this property, use the corresponding
name-value argument when you create the Convolution1DLayer object.
Value to pad data, specified as one of these values:
PaddingValue | Description | Example |
|---|---|---|
| Scalar | Pad with the specified scalar value. | |
"symmetric-include-edge" | Pad using mirrored values of the input, including the edge values. | |
"symmetric-exclude-edge" | Pad using mirrored values of the input, excluding the edge values. | |
"replicate" | Pad using repeated border elements of the input. |
The Convolution1DLayer object stores this property as a character vector or double type.
Data Types: double | char
This property is read-only after object creation. To set this property, use the corresponding
name-value argument when you create the Convolution1DLayer object.
Number of input channels, specified as one of these values:
"auto"— Automatically determine the number of input channels at training time.Positive integer — Configure the layer for the specified number of input channels.
NumChannelsand the number of channels in the layer input data must match. For example, if the input is an RGB image, thenNumChannelsmust be 3. If the input is the output of a convolutional layer with 16 filters, thenNumChannelsmust be 16.
The Convolution1DLayer object stores this property as a character vector or double type.
Data Types: double | char
Parameters and Initialization
Function to initialize the weights, specified as one of the following:
"glorot"— Initialize the weights with the Glorot initializer [1] (also known as the Xavier initializer). The Glorot initializer independently samples from a normal distribution with a mean of zero and a variance of2/(numIn + numOut), wherenumIn = FilterSize*NumChannelsandnumOut = FilterSize*NumFilters."he"— Initialize the weights with the He initializer [2]. The He initializer samples from a normal distribution with a mean of zero and a variance of2/numIn, wherenumIn = FilterSize*NumChannels."narrow-normal"— Initialize the weights by independently sampling from a normal distribution with a mean of zero and a standard deviation of 0.01."zeros"— Initialize the weights with zeros."ones"— Initialize the weights with ones.Function handle — Initialize the weights with a custom function. If you specify a function handle, then the function syntax must be of the form
weights = func(sz), whereszis the size of the weights. For an example, see Specify Custom Weight Initialization Function.
The layer only initializes the weights when the Weights property is
empty.
The Convolution1DLayer object stores this property as a character vector or a
function handle.
Data Types: char | string | function_handle
Function to initialize the biases, specified as one of these values:
"zeros"— Initialize the biases with zeros."ones"— Initialize the biases with ones."narrow-normal"— Initialize the biases by independently sampling from a normal distribution with a mean of zero and a standard deviation of 0.01.Function handle — Initialize the biases with a custom function. If you specify a function handle, then the function must have the form
bias = func(sz), whereszis the size of the biases.
The layer initializes the biases only when the Bias property is
empty.
The Convolution1DLayer object stores this property as a character vector or a
function handle.
Data Types: char | string | function_handle
Layer weights for the convolution operation, specified as a
FilterSize-by-NumChannels-by-NumFilters
numeric array or [].
The layer weights are learnable parameters. You can specify the initial value of the weights
directly using the Weights property of the layer. When
you train a network, if the Weights property of the layer
is nonempty, then the trainnet
function uses the Weights property as the initial value.
If the Weights property is empty, then the software uses
the initializer specified by the WeightsInitializer
property of the layer.
Data Types: single | double
Layer biases for the convolution operation, specified as a
1-by-NumFilters numeric array or [].
The layer biases are learnable parameters. When you train a neural network, if Bias is nonempty, then the trainnet
function uses the Bias property as the initial value. If
Bias is empty, then software uses the initializer
specified by the BiasInitializer property.
Data Types: single | double
Learning Rate and Regularization
Learning rate factor for the weights, specified as a nonnegative scalar.
The software multiplies this factor by the global learning rate to determine the learning rate for the weights in this layer. For example, if WeightLearnRateFactor is 2, then the learning rate for the weights in this layer is twice the current global learning rate. The software determines the global learning rate based on the settings you specify using the trainingOptions function.
Data Types: double
Learning rate factor for the biases, specified as a nonnegative scalar.
The software multiplies this factor by the global learning rate to determine the learning rate for the biases in this layer. For example, if BiasLearnRateFactor is 2, then the learning rate for the biases in the layer is twice the current global learning rate. The software determines the global learning rate based on the settings you specify using the trainingOptions function.
The Convolution1DLayer object stores this property as double
type.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
L2 regularization factor for the weights, specified as a nonnegative scalar.
The software multiplies this factor by the global L2 regularization factor to determine the L2 regularization for the weights in this layer. For example, if WeightL2Factor is 2, then the L2 regularization for the weights in this layer is twice the global L2 regularization factor. You can specify the global L2 regularization factor using the trainingOptions function.
Data Types: double
L2 regularization factor for the biases, specified as a nonnegative scalar.
The software multiplies this factor by the global L2 regularization factor to determine the L2 regularization for the biases in this layer. For example, if BiasL2Factor is 2, then the L2 regularization for the biases in this layer is twice the global L2 regularization factor. The software determines the global L2 regularization factor based on the settings you specify using the trainingOptions function.
The Convolution1DLayer object stores this property as double
type.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Layer
This property is read-only.
Number of inputs to the layer, stored as 1. This layer accepts a
single input only.
Data Types: double
This property is read-only.
Input names, stored as {'in'}. This layer accepts a single input
only.
Data Types: cell
This property is read-only.
Number of outputs from the layer, stored as 1. This layer has a
single output only.
Data Types: double
This property is read-only.
Output names, stored as {'out'}. This layer has a single output
only.
Data Types: cell
Examples
Create a 1-D convolutional layer with 96 filters of width of 11.
layer = convolution1dLayer(11,96);
Include a 1-D convolutional layer in a Layer array.
layers = [
sequenceInputLayer(3,MinLength=20)
layer
reluLayer
globalMaxPooling1dLayer
fullyConnectedLayer(10)
softmaxLayer]layers =
6×1 Layer array with layers:
1 '' Sequence Input Sequence input with 3 channels
2 '' 1-D Convolution 96 11 convolutions with stride 1 and padding [0 0]
3 '' ReLU ReLU
4 '' 1-D Global Max Pooling 1-D global max pooling
5 '' Fully Connected Fully connected layer with output size 10
6 '' Softmax Softmax
Algorithms
A 1-D convolutional layer applies sliding convolutional filters to 1-D input. The layer convolves the input by moving the filters along the input and computing the dot product of the weights and the input, then adding a bias term.
The dimension that the layer convolves over depends on the layer input:
For time series and vector sequence input (data with three dimensions corresponding to the channels, observations, and time steps), the layer convolves over the time dimension.
For 1-D image input (data with three dimensions corresponding to the spatial pixels, channels, and observations), the layer convolves over the spatial dimension.
For 1-D image sequence input (data with four dimensions corresponding to the spatial pixels, channels, observations, and time steps), the layer convolves over the spatial dimension.
Most layers in a layer array or layer graph pass data to subsequent layers as formatted
dlarray objects.
The format of a dlarray object is a string of characters in which each
character describes the corresponding dimension of the data. The format consists of one or
more of these characters:
"S"— Spatial"C"— Channel"B"— Batch"T"— Time"U"— Unspecified
For example, you can represent vector sequence data as a 3-D array, in which the first
dimension corresponds to the channel dimension, the second dimension corresponds to the
batch dimension, and the third dimension corresponds to the time dimension. This
representation is in the format "CBT" (channel, batch, time).
You can interact with these dlarray objects in automatic differentiation
workflows, such as those for:
developing a custom layer
using a
functionLayerobjectusing the
forwardandpredictfunctions withdlnetworkobjects
This table shows the supported input formats of Convolution1DLayer objects and the
corresponding output format. If the software passes the output of the layer to a custom
layer that does not inherit from the nnet.layer.Formattable class, or to
a FunctionLayer object with the Formattable property set
to 0 (false), then the layer receives an unformatted
dlarray object with dimensions ordered according to the formats in this
table. The formats listed here are only a subset of the formats that the layer supports. The
layer might support additional formats, such as formats with additional
"S" (spatial) or "U" (unspecified)
dimensions.
| Input Format | Output Format |
|---|---|
|
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References
[1] Glorot, Xavier, and Yoshua Bengio. "Understanding the Difficulty of Training Deep Feedforward Neural Networks." In Proceedings of the Thirteenth International Conference on Artificial Intelligence and Statistics, 249–356. Sardinia, Italy: AISTATS, 2010. https://proceedings.mlr.press/v9/glorot10a/glorot10a.pdf
[2] He, Kaiming, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. "Delving Deep into Rectifiers: Surpassing Human-Level Performance on ImageNet Classification." In 2015 IEEE International Conference on Computer Vision (ICCV), 1026–34. Santiago, Chile: IEEE, 2015. https://doi.org/10.1109/ICCV.2015.123
Extended Capabilities
Usage notes and limitations:
You can generate generic C/C++ code that does not depend on third-party libraries and deploy the generated code to hardware platforms.
Usage notes and limitations:
You can generate CUDA code that is independent of deep learning libraries and deploy the generated code to platforms that use NVIDIA® GPU processors.
Version History
Introduced in R2021b
See Also
trainnet | trainingOptions | dlnetwork | sequenceInputLayer | lstmLayer | bilstmLayer | gruLayer | maxPooling1dLayer | averagePooling1dLayer | globalMaxPooling1dLayer | globalAveragePooling1dLayer | transposedConv1dLayer | exportNetworkToSimulink | Convolution 1D
Layer
Topics
- Sequence Classification Using 1-D Convolutions
- Sequence-to-Sequence Classification Using 1-D Convolutions
- Sequence Classification Using Deep Learning
- Sequence-to-Sequence Classification Using Deep Learning
- Sequence-to-Sequence Regression Using Deep Learning
- Time Series Forecasting Using Deep Learning
- Long Short-Term Memory Neural Networks
- List of Deep Learning Layers
- Deep Learning Tips and Tricks
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