Documentation

Divide

Divide one input by another

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  • Library:

  • Simulink / Math Operations

Description

TheDivideblock outputs the result of dividing its first input by its second. The inputs can be scalars, a scalar and a nonscalar, or two nonscalars that have the same dimensions. TheDivideblock is functionally aProductblock that has two block parameter values preset:

  • Multiplication —Element-wise(.*)

  • Number of Inputs —*/

Setting nondefault values for either of those parameters can change aDivideblock to be functionally equivalent to aProductblock or aProduct of Elementsblock.

Ports

Input

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Input signal to be multiplied with other inputs.

Dependencies

To enable one or moreXports, specify one or more*characters for theNumber of inputsparameter.

Data Types:single|double|int8|int16|int32|uint8|uint16|uint32|Boolean|fixed point

Input signal for division or inversion operations.

Dependencies

To enable one or more÷ports, specify one or more/characters for theNumber of inputsparameter.

Data Types:single|double|int8|int16|int32|uint8|uint16|uint32|Boolean|fixed point

First input to multiply or divide, provided as a scalar, vector, matrix, or N-D array.

Data Types:single|double|int8|int16|int32|uint8|uint16|uint32|Boolean|fixed point

Nth input to multiply or divide, provided as a scalar, vector, matrix, or N-D array.

Data Types:single|double|int8|int16|int32|uint8|uint16|uint32|Boolean|fixed point

Output

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Output computed by multiplying, dividing, or inverting inputs.

Data Types:single|double|int8|int16|int32|uint8|uint16|uint32|Boolean|fixed point

Parameters

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Main

Control two properties of the block:

  • The number of input ports on the block

  • Whether each input is multiplied or divided into the output

When you specify:

  • 1or*or/

    The block has one input port. In element-wise mode, the block processes the input as described for theProduct of Elementsblock. In matrix mode, if the parameter value is1or*, the block outputs the input value. If the value is/, the input must be a square matrix (including a scalar as a degenerate case) and the block outputs the matrix inverse. SeeElement-Wise ModeandMatrix Modefor more information.

  • Integer value > 1

    The block has the number of inputs given by the integer value. The inputs are multiplied together in element-wise mode or matrix mode, as specified by theMultiplicationparameter. SeeElement-Wise ModeandMatrix Modefor more information.

  • Unquoted string of two or more*and/characters

    The block has the number of inputs given by the length of the character vector. Each input that corresponds to a*character is multiplied into the output. Each input that corresponds to a/character is divided into the output. The operations occur in element-wise mode or matrix mode, as specified by theMultiplicationparameter. SeeElement-Wise ModeandMatrix Modefor more information.

Programmatic Use

Block Parameter:Inputs
Type:character vector
Values:'2' | '*' | '**' | '*/' | '*/*' | ...
Default:'*/'

Specify whether the block performsElement-wise(.*)orMatrix(*)multiplication.

Programmatic Use

Block Parameter:Multiplication
Type:character vector
Values:'Element-wise(.*)' | 'Matrix(*)'
Default:'Element-wise(.*)'

Specify the dimension to multiply over asAll dimensions, orSpecified dimension. When you selectSpecified dimension, you can specify theDimensionas1or2.

Dependencies

To enable this parameter, setNumber of inputsto*andMultiplicationtoElement-wise (.*).

Programmatic Use

Block Parameter:CollapseMode
Type:character vector
Values:'All dimensions' | 'Specified dimension'
Default:'All dimensions'

Specify the dimension to multiply over as an integer less than or equal to the number of dimensions of the input signal.

Dependencies

To enable this parameter, set:

  • Number of inputsto*

  • MultiplicationtoElement-wise (.*)

  • Multiply overtoSpecified dimension

Programmatic Use

Block Parameter:CollapseDim
Type:character vector
Values:'1' | '2' | ...
Default:'1'

Specify the sample time as a value other than -1. For more information, seeSpecify Sample Time.

Dependencies

This parameter is not visible unless it is explicitly set to a value other than-1. To learn more, seeBlocks for Which Sample Time Is Not Recommended.

Programmatic Use

Block Parameter:SampleTime
Type:character vector
Values:scalar
Default:'-1'

Signal Attributes

Specify if input signals must all have the same data type. If you enable this parameter, then an error occurs during simulation if the input signal types are different.

Programmatic Use

Block Parameter:InputSameDT
Type:character vector
Values:'off' | 'on'
Default:'off'

Lower value of the output range that Simulink®checks.

Simulink uses the minimum to perform:

Note

Output minimumdoes not saturate or clip the actual output signal. Use theSaturationblock instead.

Programmatic Use

Block Parameter:OutMin
Type: character vector
Values:'[ ]'| scalar
Default:'[ ]'

Upper value of the output range that Simulink checks.

Simulink uses the maximum value to perform:

Note

Output maximumdoes not saturate or clip the actual output signal. Use theSaturationblock instead.

Programmatic Use

Block Parameter:OutMax
Type: character vector
Values:'[ ]'| scalar
Default:'[ ]'

Choose the data type for the output. The type can be inherited, specified directly, or expressed as a data type object such asSimulink.NumericType. For more information, seeControl Signal Data Types.

When you select an inherited option, the block behaves as follows:

  • 继承: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 typeint8by a gain ofint16andASIC/FPGAis specified as the targeted hardware type, the output data type issfix24. IfUnspecified (assume 32-bit Generic), in other words, a generic 32-bit microprocessor, is specified as the target hardware, the output data type isint32. 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.

    这并不总是可能的opti的软件mize 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继承:Same as input.

    • Explicitly specify a default data type such asfixdt(1,32,16)and then use the Fixed-Point Tool to propose data types for your model. For more information, seefxptdlg.

    • To specify your own inheritance rule, use继承:Inherit via back propagationand then use aData Type Propagationblock. Examples of how to use this block are available in the Signal Attributes libraryData Type Propagation Examplesblock.

  • 继承:Inherit via back propagation— Use data type of the driving block.

  • 继承:Same as first input— Use data type of first input signal.

Programmatic Use

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)'|''
Default:'Inherit: Inherit via internal rule'

Select this parameter to prevent the fixed-point tools from overriding theOutputdata type you specify on the block. For more information, seeUse Lock Output Data Type Setting(Fixed-Point Designer).

Programmatic Use

Block Parameter:LockScale
Type:character vector
Values:'off' | 'on'
Default:'off'

Select the rounding mode for fixed-point operations. You can select:

Ceiling

Rounds positive and negative numbers toward positive infinity. Equivalent to the MATLAB®ceilfunction.

Convergent

Rounds number to the nearest representable value. If a tie occurs, rounds to the nearest even integer. Equivalent to the Fixed-Point Designer™convergentfunction.

Floor

Rounds positive and negative numbers toward negative infinity. Equivalent to the MATLABfloorfunction.

Nearest

Rounds number to the nearest representable value. If a tie occurs, rounds toward positive infinity. Equivalent to the Fixed-Point Designernearestfunction.

Round

Rounds number to the nearest representable value. If a tie occurs, rounds positive numbers toward positive infinity and rounds negative numbers toward negative infinity. Equivalent to the Fixed-Point Designerroundfunction.

Simplest

Chooses between rounding toward floor and rounding toward zero to generate rounding code that is as efficient as possible.

Zero

Rounds number toward zero. Equivalent to the MATLABfixfunction.

For more information, seeRounding(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

Block Parameter:RndMeth
Type:character vector
Values:'Ceiling' | 'Convergent' | 'Floor' | 'Nearest' | 'Round' | 'Simplest' | 'Zero'
Default:'Floor'

Specify whether overflows saturate or wrap.

Action Rationale Impact on Overflows Example

Select this check box (on).

Your model has possible overflow, and you want explicit saturation protection in the generated code.

Overflows saturate to either the minimum or maximum value that the data type can represent.

The maximum value that theint8(signed, 8-bit integer) data type can represent is 127. Any block operation result greater than this maximum value causes overflow of the 8-bit integer. With the check box selected, the block output saturates at 127. Similarly, the block output saturates at a minimum output value of -128.

Do not select this check box (off).

You want to optimize efficiency of your generated code.

You want to avoid overspecifying how a block handles out-of-range signals. For more information, seeCheck for Signal Range Errors.

Overflows wrap to the appropriate value that is representable by the data type.

The maximum value that theint8(signed, 8-bit integer) data type can represent is 127. Any block operation result greater than this maximum value causes overflow of the 8-bit integer. With the check box cleared, the software interprets the overflow-causing value asint8, which can produce an unintended result. For example, a block result of 130 (binary 1000 0010) expressed asint8, is -126.

When you select this check box, saturation applies to every internal operation on the block, not just the output, or result. Usually, the code generation process can detect when overflow is not possible. In this case, the code generator does not produce saturation code.

Programmatic Use

Block Parameter:SaturateOnIntegerOverflow
Type:character vector
Values:'off' | 'on'
Default:'off'

模型的例子

Divide Inputs of Different Dimensions Using the Divide Block

Divide Inputs of Different Dimensions Using the Divide Block

This example shows how to perform element-wise (.*) division of two inputs using the Divide block. In this example, the Divide block divides two scalars, a vector by a scalar, a scalar by a vector, and two matrices.
Open Model

Block Characteristics

Data Types

double|single|Boolean|base integer|fixed point

Multidimensional Signals

Yes

Variable-Size Signals

Yes

Extended Capabilities

PLC Code Generation
Generate Structured Text code using Simulink® PLC Coder™.

Fixed-Point Conversion
浮点算法转换为定点using Fixed-Point Designer™.

See Also

||

Introduced before R2006a

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