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Dot Product - Generate dot product of two vectors

Library

Math Operations

Description

The Dot Product block generates the dot product of the vectors at its inputs. The scalar output, y, is equal to the MATLAB operation

y = sum(conj(u1) .* u2 )

where u1 and u2 represent the vectors at the block's top and bottom inputs, respectively. (See How to Rotate a Block in the Simulink User's Guide for a description of the port order for various block orientations.) The inputs can be vectors, column vectors (single-column 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 complex-valued 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

To perform element-by-element multiplication without summing, use the Product block.

Data Type Support

The Dot Product block accepts and outputs signals of any numeric data type supported by Simulink software, including fixed-point data types.

For a discussion on the data types supported by Simulink software, see Data Types Supported by Simulink.

Parameters and Dialog Box

The Main pane of the Dot Product block dialog box appears as follows:

The Signal Attributes pane of the Dot Product block dialog box appears as follows:

Sample time (-1 for inherited)

Specify the time interval between samples. To inherit the sample time, set this parameter to -1. See How to Specify the Sample Time in the Simulink User's Guide for more information.

Require all inputs to have same data type

Select to require all inputs to have the same data type.

Output minimum

Specify the minimum value that the block should output. The default value, [], is equivalent to -Inf. Simulink software uses this value to perform:

• Simulation range checking (see Checking Signal Ranges)

• Automatic scaling of fixed-point data types

Output maximum

Specify the maximum value that the block should output. The default value, [], is equivalent to Inf. Simulink software uses this value to perform:

• Simulation range checking (see Checking Signal Ranges)

• Automatic scaling of fixed-point data types

Output data type

Specify the output data type. You can set it to:

• A rule that inherits a data type, for example, Inherit: Inherit via back propagation

• The name of a built-in data type, for example, single

• The name of a data type object, for example, a Simulink.NumericType object

• An expression that evaluates to a 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 data type parameter.

See Specifying Block Output Data Types for more information.

Lock output data type setting against changes by the fixed-point tools

Select to lock the output data type setting of this block against changes by the Fixed-Point Tool and the Fixed-Point Advisor. For more information, see Fixed-Point Tool and Fixed-Point Advisor in the Simulink Fixed Point documentation.

Integer rounding mode

Select the rounding mode for fixed-point operations. For more information, see Rounding in the Simulink Fixed Point User's Guide.

Saturate on integer overflow

Select to have overflows saturate.

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 which case, no saturation code is necessary.

Characteristics

Direct Feedthrough	Yes
Sample Time	Specified in the Sample time parameter
Scalar Expansion	No
States	0
Dimensionalized	Yes
Zero-Crossing Detection	No

DocBlock

Embedded MATLAB Function

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