ReLU Layer
Libraries:
Deep Learning Toolbox /
Deep Learning Layers /
Activation Layers
Description
The ReLU Layer block applies the rectified linear unit (ReLU) activation operation on layer input. ReLU activation performs a nonlinear threshold operation where any input value less than zero is set to zero.
This operation is equivalent to:
The exportNetworkToSimulink
function generates this block to represent a reluLayer
object.
Because it applies an element-wise operation, this block supports input data of any format and
outputs data that has the same dimensions and format as the input.
Ports
Input
Port_1 — Input data
scalar | vector | matrix
The data on which to perform the nonlinear threshold operation.
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
| fixed point
Output
Port_1 — Output data
scalar | vector | matrix
The result of performing the nonlinear threshold operation on the input matrix. Values less than zero in the input matrix become zero.
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
| fixed point
Parameters
To edit block parameters interactively, use the Property Inspector. From the Simulink® Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.
Data Types
Output minimum — Minimum output value for range checking
[]
(default) | scalar
Lower value of the output range that the software checks.
The software uses the minimum to perform:
Parameter range checking (see Specify Minimum and Maximum Values for Block Parameters (Simulink)) for some blocks.
Simulation range checking (see Specify Signal Ranges (Simulink) and Enable Simulation Range Checking (Simulink)).
Automatic scaling of fixed-point data types.
Optimization of the code that you generate from the model. This optimization can remove algorithmic code and affect the results of some simulation modes such as SIL or external mode. For more information, see Optimize using the specified minimum and maximum values (Embedded Coder).
Tips
Output minimum does not saturate or clip the actual output signal. Use the Saturation (Simulink) block instead.
Programmatic Use
To set the block parameter value programmatically, use
the set_param
(Simulink) function.
Parameter: | OutMin |
Values: | '[]' (default) | scalar in quotes |
Output maximum — Maximum output value for range checking
[]
(default) | scalar
Upper value of the output range that the software checks.
The software uses the maximum value to perform:
Parameter range checking (see Specify Minimum and Maximum Values for Block Parameters (Simulink)) for some blocks.
Simulation range checking (see Specify Signal Ranges (Simulink) and Enable Simulation Range Checking (Simulink)).
Automatic scaling of fixed-point data types.
Optimization of the code that you generate from the model. This optimization can remove algorithmic code and affect the results of some simulation modes such as SIL or external mode. For more information, see Optimize using the specified minimum and maximum values (Embedded Coder).
Tips
Output maximum does not saturate or clip the actual output signal. Use the Saturation (Simulink) block instead.
Programmatic Use
To set the block parameter value programmatically, use
the set_param
(Simulink) function.
Parameter: | OutMax |
Values: | '[]' (default) | scalar in quotes |
Output data type — Data type of output
Inherit: Inherit via internal
rule
(default) | Inherit: Keep MSB
| Inherit: Keep LSB
| Inherit: Inherit via back propagation
| Inherit: Same as first input
| <data type expression>
Choose the data type for the output. The type can be inherited, specified directly, or expressed as a data type object such as Simulink.NumericType
. When you choose Inherit: Inherit via internal rule
,
Simulink chooses a data type to balance numerical accuracy, performance, and generated code
size, while taking into account the properties of the embedded target hardware.
Programmatic Use
To set the block parameter value programmatically, use
the set_param
(Simulink) function.
Parameter: | OutDataTypeStr |
Values: | 'Inherit: Inherit via internal
rule' (default) | 'Inherit: Keep MSB' | 'Inherit: Keep LSB' | 'Inherit: Inherit via back propagation' | 'Inherit: Same as first input' | <data type expression> |
Lock output data type setting against changes by the fixed-point tools — Option to prevent fixed-point tools from overriding Output data type
off
(default) | on
Select this parameter to prevent the fixed-point tools from overriding the Output data type you specify on the block. For more information, see Use Lock Output Data Type Setting (Fixed-Point Designer).
Programmatic Use
To set the block parameter value programmatically, use
the set_param
(Simulink) function.
Parameter: | LockScale |
Values: | 'off' (default) | 'on' |
Integer rounding mode — Rounding mode for fixed-point operations
Floor
(default) | Ceiling
| Convergent
| Nearest
| Round
| Simplest
| Zero
Specify the rounding mode for fixed-point operations. For more information, see Rounding Modes (Fixed-Point Designer).
Block parameters always round to the nearest representable value. To control the rounding of a block parameter, enter an expression using a MATLAB® rounding function into the mask field.
Programmatic Use
To set the block parameter value programmatically, use
the set_param
(Simulink) function.
Parameter: | RndMeth |
Values: | 'Floor' (default) | 'Ceiling' | 'Convergent' | 'Nearest' | 'Round' | 'Simplest' | 'Zero' |
Saturate on integer overflow — Method of overflow action
off
(default) | on
Specify whether overflows saturate or wrap.
on
— Overflows saturate to either the minimum or maximum value that the data type can represent.off
— Overflows wrap to the appropriate value that the data type can represent.
For example, the maximum value that the signed 8-bit integer int8
can represent is 127. Any block operation result greater than this maximum value causes overflow of the 8-bit integer.
With this parameter selected, the block output saturates at 127. Similarly, the block output saturates at a minimum output value of -128.
With this parameter cleared, the software interprets the overflow-causing value as
int8
, which can produce an unintended result. For example, a block result of 130 (binary 1000 0010) expressed asint8
is -126.
Tips
Consider selecting this parameter when your model has a possible overflow and you want explicit saturation protection in the generated code.
Consider clearing this parameter when you want to optimize efficiency of your generated code. Clearing this parameter also helps you to avoid overspecifying how a block handles out-of-range signals. For more information, see Troubleshoot Signal Range Errors (Simulink).
When you select this parameter, saturation applies to every internal operation on the block, not just the output or result.
In general, the code generation process can detect when overflow is not possible. In this case, the code generator does not produce saturation code.
Programmatic Use
To set the block parameter value programmatically, use
the set_param
(Simulink) function.
Parameter: | SaturateOnIntegerOverflow |
Values: | 'off' (default) | 'on' |
Execution
Sample time — Option to specify sample time
-1
(default) | scalar
Specify the discrete interval between sample time hits or specify another type of sample time, such as continuous (0
) or inherited (-1
). For more options, see Types of Sample Time (Simulink).
By default, the block inherits its sample time based upon the context of the block within the model.
Programmatic Use
Block Parameter: SampleTime |
Type: character vector |
Values: scalar |
Default: '-1' |
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
Version History
Introduced in R2024b
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