Relational Operator
Perform specified relational operation on inputs
 Library:
Simulink / Commonly Used Blocks
Simulink / Logic and Bit Operations
HDL Coder / Commonly Used Blocks
HDL Coder / HDL Floating Point Operations
HDL Coder / Logic and Bit Operations
Description
The Relational Operator block performs the specified relational operation on the input. The value you choose for the Relational operator parameter determines whether the block accepts one or two input signals.
TwoInput Mode
By default, the Relational Operator block compares two inputs using the Relational operator parameter that you specify. The first input corresponds to the top input port and the second input to the bottom input port. (See Port Location After Rotating or Flipping for a description of the port order for various block orientations.)
You can specify one of the following operations in twoinput mode:
Operation  Description 

 True if the first input is equal to the second input 
 True if the first input is not equal to the second input 
 True if the first input is less than the second input 
 True if the first input is less than or equal to the second input 
 True if the first input is greater than or equal to the second input 
 True if the first input is greater than the second input 
You can specify inputs as scalars, arrays, or a combination of a scalar and an array.
For...  The output is... 

Scalar inputs  A scalar 
Array inputs  An array of the same dimensions, where each element is the result of an elementbyelement comparison of the input arrays 
Mixed scalar and array inputs  An array, where each element is the result of a comparison between the scalar and the corresponding array element 
The input with the smaller positive range is converted to the data type of the other input offline using roundtonearest and saturation. This conversion occurs before the comparison.
You can specify the output data type using the Output data type
parameter. The output equals 1
for true and 0
for false.
Tip
Select an output data type that represents zero exactly. Data types that satisfy this condition include signed and unsigned integers and any floatingpoint data type.
OneInput Mode
When you select one of the following operations for Relational operator, the block switches to oneinput mode.
Operation  Description 

 True if the input is 
 True if the input is 
 True if the input is finite 
For an input that is not floating point, the block produces the following output.
Data Type  Operation  Block Output 


 False 
 False  
 True 
Rules for Data Type Propagation
The following rules apply for data type propagation when your block has one or more input ports with unspecified data types.
When the block is in...  And...  The block uses... 

Twoinput mode  Both input ports have unspecified data types 
double
as the default data type for both inputs 
One input port has an unspecified data type  The data type from the specified input port as the default data type of the other port  
Oneinput mode  The input port has an unspecified data type 
double
as the default data type for the input 
Ports
Input
Output
Parameters
Model Examples
Block Characteristics
Data Types 

Direct Feedthrough 

Multidimensional Signals 

VariableSize Signals 

ZeroCrossing Detection 

Extended Capabilities
Version History
Introduced before R2006a