ArrayVector Subtract
Subtract vector from array along specified dimension
Library
Math Functions / Matrices and Linear Algebra / Matrix Operations
dspmtrx3
Description
The ArrayVector Subtract block subtracts the values in the input vector V from the values in the specified dimension of the Ndimensional input array A.
The length of the input V must be the same as the length of the specified dimension of A. The ArrayVector Subtract block subtracts each element of V from the corresponding element along that dimension of A.
Consider a 3dimensional
MbyNbyP input array
A(i,j,k) and an Nby1 input vector
V. When the Subtract along dimension
parameter is set to 2
, the output of the block
Y(i,j,k) is
$$Y(i,j,k)=A(i,j,k)V(j)$$
where
$$\begin{array}{l}1\le i\le M\\ 1\le j\le N\\ 1\le k\le P\end{array}$$
The output of the ArrayVector Subtract block is the same size as the input array, A. This block accepts real and complex floatingpoint and fixedpoint inputs.
FixedPoint Data Types
The following diagram shows the data types used within the ArrayVector Subtract block for fixedpoint signals.
When you specify the vector V on the Main pane of the block mask, you must specify the data type and scaling properties of its elements in the Vector (V) parameter on the Data Types tab. When the vector comes in through the block port, its elements inherit their data type and scaling from the driving block.
The output of the subtractor is in the accumulator data type.
You can set the vector, accumulator, and output data types in the block dialog as discussed below.
Parameters
Main Tab
 Subtract along dimension
Specify the dimension along which to subtract the elements of vector V from the input array A.
 Vector (V) source
Specify the source of the vector, V. The vector can come from the
Input port
or from aDialog parameter
. Vector (V)
Specify the vector, V. This parameter is visible only when you select
Dialog parameter
for the Vector (V) source parameter.
Data Types
Note
Floatingpoint inheritance takes precedence over the data type settings defined on this pane. When inputs are floating point, the block ignores these settings, and all internal data types are floating point.
 Rounding mode
Specify the rounding mode for fixedpoint operations as one of the following:
Floor
Ceiling
Convergent
Nearest
Round
Simplest
Zero
For more details, see rounding mode.
Note
The Rounding mode and Saturate on integer overflow settings have no effect on numerical results when both of these conditions are met:
Accumulator is
Inherit: Inherit via internal rule
Output is
Inherit: Same as accumulator
With these data type settings, the block is effectively operating in full precision mode.
 Saturate on integer overflow
When you select this parameter, the block saturates the result of its fixedpoint operation. When you clear this parameter, the block wraps the result of its fixedpoint operation. For details on
saturate
andwrap
, see overflow mode for fixedpoint operations. Vector (V)
Use this parameter to specify the word and fraction lengths for the elements of the vector, V. You can set this parameter to:
A rule that inherits a data type, for example,
Inherit: Same word length as input
An expression that evaluates to a valid data type, for example,
fixdt(1,16,0)
Click the Show data type assistant button to display the Data Type Assistant, which helps you set the Accumulator parameter.
See Specify Data Types Using Data Type Assistant (Simulink) for more information.
Note
The Vector (V) parameter on the Data Types pane is only visible when you select
Dialog parameter
for the Vector (V) source parameter on the Main pane of the block mask. When the vector comes in through the block's input port, the data type and scaling of its elements are inherited from the driving block. Accumulator
Specify the accumulator data type. See FixedPoint Data Types for illustrations depicting the use of the accumulator data type in this block. You can set this parameter to:
A rule that inherits a data type, for example,
Inherit: Inherit via internal rule
. For more information on this rule, see Inherit via Internal Rule.A rule that inherits a data type, for example,
Inherit: Same as first input
.An expression that evaluates to a valid data type, for example,
fixdt(1,16,0)
Click the Show data type assistant button to display the Data Type Assistant, which helps you set the Accumulator parameter.
See Specify Data Types Using Data Type Assistant (Simulink) for more information.
 Output
Specify the output data type. See FixedPoint Data Types for illustrations depicting the use of the output data type in this block. You can set it to:
A rule that inherits a data type, for example,
Inherit: Same as accumulator
A rule that inherits a data type, for example,
Inherit: Same as first input
.An expression that evaluates to a valid data type, for example,
fixdt(1,16,0)
Click the Show data type assistant button to display the Data Type Assistant, which helps you set the Output parameter.
See Control Data Types of Signals (Simulink) for more information.
 Minimum
Specify the minimum value that the block should output. The default value is
[]
(unspecified). Simulink^{®} uses this value to perform:Simulation range checking (see Specify Signal Ranges (Simulink))
Automatic scaling of fixedpoint data types
 Maximum
Specify the maximum value that the block should output. The default value is
[]
(unspecified). Simulink uses this value to perform:Simulation range checking (see Specify Signal Ranges (Simulink))
Automatic scaling of fixedpoint data types
 Lock data type settings against changes by the fixedpoint tools
Select this parameter to prevent the fixedpoint tools from overriding the data types you specify on the block mask.
Supported Data Types
Port  Supported Data Types 

A 

V 

Output 

Extended Capabilities
Version History
Introduced in R2007b