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Generate dot product of two vectors
Simulink / Math Operations
The Dot Product block generates the dot product of the input vectors. The
scalar output, y
, is equal to the MATLAB^{®} operation
y = sum(conj(u1) .* u2 )
where u1
and u2
represent the input vectors. The
inputs can be vectors, column vectors (singlecolumn matrices), or scalars. If both
inputs are vectors or column vectors, they must be the same length. If
u1
and u2
are both column vectors, the block
outputs the equivalent of the MATLAB expression u1'*u2
.
The elements of the input vectors can be real or complexvalued signals. The signal type (complex or real) of the output depends on the signal types of the inputs.
Input 1  Input 2  Output 

real 
real 
real 
real 
complex 
complex 
complex 
real 
complex 
complex 
complex 
complex 
Port_1
— First operand input signalSignal representing the first operand to the dot product calculation.
Data Types: single
 double
 int8
 int16
 int32
 uint8
 uint16
 uint32
 fixed point
Port_2
— Second operand input signalSignal representing the second operand to the dot product calculation.
Data Types: single
 double
 int8
 int16
 int32
 uint8
 uint16
 uint32
 fixed point
Port_1
— Dot product output signalOutput signal resulting from the dot product calculation of the two input signals.
Data Types: single
 double
 int8
 int16
 int32
 uint8
 uint16
 uint32
 fixed point
Require all inputs to have the same data type
— Require all inputs to have the same data typeon
(default)  off
Clear this check box for all the inputs to have different data types.
Block Parameter:
InputSameDT 
Type: character vector 
Values: 'on'
 'off' 
Default:
'on' 
Output minimum
— Minimum output value for range checking[]
(default)  scalarLower value of the output range that Simulink^{®} checks.
Simulink uses the minimum to perform:
Parameter range checking (see Specify Minimum and Maximum Values for Block Parameters) for some blocks.
Simulation range checking (see Signal Ranges and Enable Simulation Range Checking).
Automatic scaling of fixedpoint 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 (Simulink Coder).
Output minimum does not saturate or clip the actual output signal. Use the Saturation block instead.
Block Parameter:
OutMin 
Type: character vector 
Values: '[ ]' 
scalar 
Default: '[ ]' 
Output maximum
— Maximum output value for range checking[]
(default)  scalarSpecify the upper value of the output range that Simulink checks as a finite, real, double, scalar value.
If you specify a bus object as the data type for this block, do not set the maximum value for bus data on the block. Simulink ignores this setting. Instead, set the maximum values for bus elements of the bus object specified as the data type. For information on the Maximum parameter for a bus element, see Simulink.BusElement
.
Simulink uses the maximum value to perform:
Parameter range checking (see Specify Minimum and Maximum Values for Block Parameters) for some blocks.
Simulation range checking (see Signal Ranges and Enable Simulation Range Checking).
Automatic scaling of fixedpoint 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 (Simulink Coder).
Output maximum does not saturate or clip the actual output signal. Use the Saturation block instead.
Block Parameter: OutMax 
Type: character vector 
Values: scalar 
Default: '[ ]' 
Output data type
— Specify the output data typeInherit: Inherit via internal
rule
(default)  Inherit: Inherit via back propagation
 Inherit: Same as first input
 double
 single
 int8
 uint8
 int16
 uint16
 int32
 uint32
 fixdt(1,16)
 fixdt(1,16,0)
 fixdt(1,16,2^0,0)
 <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
. For more information, see
Control Signal Data Types.
When you select an inherited option, the block behaves as follows:
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.
If you change the embedded target settings, the data type
selected by the internal rule might change. For example, if
the block multiplies an input of type
int8
by a gain of
int16
and
ASIC/FPGA
is specified as
the targeted hardware type, the output data type is
sfix24
. If
Unspecified (assume 32bit
Generic)
, in other words, a generic
32bit microprocessor, is specified as the target hardware,
the output data type is int32
. If none of
the word lengths provided by the target microprocessor can
accommodate the output range, Simulink software displays an error in the Diagnostic
Viewer.
It is not always possible for the software to optimize code efficiency and numerical accuracy at the same time. If the internal rule doesn’t meet your specific needs for numerical accuracy or performance, use one of the following options:
Specify the output data type explicitly.
Use the simple choice of
Inherit: Same as
input
.
Explicitly specify a default data type such
as fixdt(1,32,16)
and then use
the FixedPoint Tool to propose data types for
your model. For more information, see fxptdlg
.
To specify your own inheritance rule, use
Inherit: Inherit via back
propagation
and then use a Data Type
Propagation block. Examples of how to use
this block are available in the Signal Attributes
library Data Type Propagation
Examples block.
Inherit: Inherit via back
propagation
— Use data type of the
driving block.
Inherit: Same as first input
— Use
data type of first input signal.
Block Parameter:
OutDataTypeStr 
Type: character vector 
Values: 'Inherit:
Inherit via internal rule 
'Inherit: Same as first input' 
'Inherit: Inherit via back
propagation'  'double'
 'single'  'int8' 
'uint8' 
'int16' 
'uint16' 
'int32' 
'uint32' 
'fixdt(1,16)' 
'fixdt(1,16,0)' 
'fixdt(1,16,2^0,0)' 
'<data type
expression>' 
Default: 'Inherit:
Inherit via internal rule' 
Lock output data type setting against changes by the fixedpoint tools
— Prevent fixedpoint tools from overriding data typesoff
(default)  on
Select to lock the output data type setting of this block against changes by the FixedPoint Tool and the FixedPoint Advisor. For more information, see Use Lock Output Data Type Setting (FixedPoint Designer).
Block Parameter:
LockScale 
Type: character vector 
Values:
'off' 
'on' 
Default:
'off' 
Integer rounding mode
— Rounding mode for fixedpoint operationsFloor
(default)  Ceiling
 Convergent
 Nearest
 Round
 Simplest
 Zero
Specify the rounding mode for fixedpoint operations. For more information, see Rounding (FixedPoint 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.
Block Parameter:
RndMeth 
Type: character vector 
Values:
'Ceiling'  'Convergent'  'Floor'  'Nearest'  'Round'  'Simplest' 
'Zero' 
Default:
'Floor' 
Saturate on integer overflow
— Method of overflow actionoff
(default)  on
Specify whether overflows saturate or wrap.
off
— Overflows wrap to the appropriate value that the data type can represent.
For example, the number 130 does not fit in a signed 8bit integer and wraps to 126.
on
— Overflows saturate to either the minimum or maximum value that the data type can represent.
For example, an overflow associated with a signed 8bit integer can saturate to 128 or 127.
Consider selecting this check box when your model has a possible overflow and you want explicit saturation protection in the generated code.
Consider clearing this check box when you want to optimize efficiency of your generated code.
Clearing this check box also helps you to avoid overspecifying how a block handles outofrange signals. For more information, see Check for Signal Range Errors.
When you select this check box, 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.
Block Parameter: SaturateOnIntegerOverflow 
Type: character vector 
Values: 'off'  'on' 
Default: 'off' 
Data Types 

Direct Feedthrough 

Multidimensional Signals 

VariableSize Signals 

ZeroCrossing Detection 

For information about HDL Code Generation, see Dot Product.
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