Divide one input by another
Math Operations
The Product and Product of Elements blocks are variants of the Divide block.
For information on the Product block, see Product.
For information on the Product of Elements block, see Product of Elements.
The Divide block 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. The Divide block is functionally a Product block that has two block parameter values preset:
Multiplication: Element-wise(.*)
Number of Inputs: */
Setting non-default values for either of those parameters can change a Divide block to be functionally equivalent to a Product block or a Product of Elements block. See the documentation of those two blocks for more information.
If any of the Divide block inputs contains a NaN
or inf
value,
or if the block generates NaN
or inf
during
execution, you might see different results when you compare the block
simulation results with the generated code. This difference is due
to the nonfinite NaN
or inf
values.
In such cases, inspect your model configuration and eliminate the
conditions that produce NaN
or inf
.
The Simulink^{®} Coder™ build process provides efficient code for matrix inverse and division operations. The following summary describes the benefits and when each benefit is available:
Benefit | Small
matrices (2-by-2 to 5-by-5) | Medium matrices (6-by-6 to 20-by-20) | Large matrices (larger than 20-by-20) |
---|---|---|---|
Faster code execution time, compared to R2011a and earlier releases | Yes | No | Yes |
Reduced ROM and RAM usage, compared to R2011a and earlier releases | Yes, for real values | Yes, for real values | Yes, for real values |
Reuse of variables | Yes | Yes | Yes |
Dead code elimination | Yes | Yes | Yes |
Constant folding | Yes | Yes | Yes |
Expression folding | Yes | Yes | Yes |
Consistency with MATLAB^{®} Coder results | Yes | Yes | Yes |
For blocks that have three or more inputs of different dimensions, the code might include an extra buffer to store temporary variables for intermediate results.
Display the Data Type Assistant.
The Data Type Assistant helps you set the Output data type parameter.
For more information, see Control Signal Data Types.
Control two properties of the block:
The number of input ports on the block
Whether each input is multiplied or divided into the output
Default: */
1
or *
or /
Has one input. In element-wise mode, processes the input as
described for the Product of Elements block.
In matrix mode, if the parameter value is 1
or *
,
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. See Element-wise Mode and Matrix Mode for more information.
Integer value > 1
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 the Multiplication parameter. See Element-wise Mode and Matrix Mode for more information.
Unquoted string of two or more *
and /
characters
Has the number of inputs given by the length of the string.
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 the Multiplication parameter.
See Element-wise Mode and Matrix Mode for more information.
Setting Number of inputs to *
and
selecting Element-wise(.*)
for Multiplication enables
the parameter Multiply over.
See Block-Specific Parameters for the command-line information.
Specify whether the Product block operates in Element-wise mode or Matrix mode.
Default: Element-wise(.*)
Element-wise(.*)
Operate in Element-wise mode.
Matrix(*)
Operate in Matrix mode.
Selecting Element-wise(.*)
and setting Number
of inputs to *
enable the following
parameter:
Multiply over
See Block-Specific Parameters for the command-line information.
Affect multiplication on matrix input.
Default: All dimensions
All dimensions
Output a scalar that is product of all elements of the matrix, or the product of their inverses, depending on the value of Number of inputs.
Specified dimension
Output a vector, the composition of which depends on the value of the Dimension parameter.
Enable this parameter by selecting Element-wise(.*)
for Multiplication and
setting Number of inputs to *
or 1
or /
.
Setting this parameter to Specified dimension
enables
the Dimension parameter.
See Block-Specific Parameters for the command-line information.
Affect multiplication on matrix input.
Default: 1
Minimum: 1
Maximum: 2
1
Output a vector that contains an element for each column of the input matrix.
2
Output a vector that contains an element for each row of the input matrix.
Each element of the output vector contains the product of all elements in the corresponding column or row of the input matrix, or the product of the inverses of those elements, depending on the value of Number of inputs:
1
or *
Multiply the values of the column or row elements
/
Multiply the inverses of the column or row elements
Enable this parameter by selecting Specified dimension
for Multiply
over.
See Block-Specific Parameters for the command-line information.
Note:
This parameter is not visible in the block dialog box unless
it is explicitly set to a value other than |
Require that all inputs have the same data type.
Default: Off
Require that all inputs have the same data type.
Do not require that all inputs have the same data type.
See Block-Specific Parameters for the command-line information.
Select to lock the output data type setting of this block against changes by the Fixed-Point Tool and the Fixed-Point Advisor.
Default: Off
Locks the output data type setting for this block.
Allows the Fixed-Point Tool and the Fixed-Point Advisor to change the output data type setting for this block.
Parameter: LockScale |
Type: string |
Value: 'off' | 'on' |
Default: 'off' |
For more information, see Use Lock Output Data Type Setting.
Specify the rounding mode for fixed-point operations.
Default: Floor
Ceiling
Rounds positive and negative numbers toward positive infinity.
Equivalent to the MATLAB ceil
function.
Convergent
Rounds number to the nearest representable value. If a tie occurs,
rounds to the nearest even integer. Equivalent to the Fixed-Point Designer™ convergent
function.
Floor
Rounds positive and negative numbers toward negative infinity.
Equivalent to the MATLAB floor
function.
Nearest
Rounds number to the nearest representable value. If a tie occurs,
rounds toward positive infinity. Equivalent to the Fixed-Point Designer nearest
function.
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 Designer round
function.
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 MATLAB fix
function.
See Block-Specific Parameters for the command-line information.
For more information, see Rounding.
Specify whether overflows saturate.
Default: Off
Overflows saturate to either the minimum or maximum value that the data type can represent.
For example, an overflow associated with a signed 8-bit integer can saturate to -128 or 127.
Overflows wrap to the appropriate value that the data type can represent.
For example, the number 130 does not fit in a signed 8-bit integer and wraps to -126.
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 out-of-range signals. For more information, see Checking 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.
Parameter: SaturateOnIntegerOverflow |
Type: string |
Value: 'off' | 'on' |
Default: 'off' |
Lower value of the output range that Simulink checks.
Default: []
(unspecified)
Specify this number as a finite, real, double, scalar value.
Simulink uses the minimum to perform:
Parameter range checking (see Control Block Parameter Value Ranges) for some blocks
Simulation range checking (see Signal Ranges and Enabling Simulation Range Checking)
Automatic scaling of fixed-point data types
Note: Output minimum does not saturate or clip the actual output signal. Use the Saturation block instead. |
Parameter: OutMin |
Type: string |
Value: '[ ]' |
Default: '[ ]' |
Upper value of the output range that Simulink checks.
Default: []
(unspecified)
Specify this number as a finite, real, double, scalar value.
Simulink uses the maximum value to perform:
Parameter range checking (see Control Block Parameter Value Ranges) for some blocks
Simulation range checking (see Signal Ranges and Enabling Simulation Range Checking)
Automatic scaling of fixed-point data types
Note: Output maximum does not saturate or clip the actual output signal. Use the Saturation block instead. |
Parameter: OutMax |
Type: string |
Value: '[ ]' |
Default: '[ ]' |
Specify the output data type.
Default: Inherit:
Inherit via internal rule
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. 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 first input
.
Explicitly specify a default data type such as fixdt(1,32,16)
and
then use the Fixed-Point 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 the first input signal.
double
Output data type is double
.
single
Output data type is single
.
int8
Output data type is int8
.
uint8
Output data type is uint8
.
int16
Output data type is int16
.
uint16
Output data type is uint16
.
int32
Output data type is int32
.
uint32
Output data type is uint32
.
fixdt(1,16,0)
Output data type is fixed point fixdt(1,16,0)
.
fixdt(1,16,2^0,0)
Output data type is fixed point fixdt(1,16,2^0,0)
.
<data type expression>
Use a data type object, for example, Simulink.NumericType
.
See Block-Specific Parameters for the command-line information.
For more information, see Control Signal Data Types.
Select the category of data to specify.
Default: Inherit
Inherit
Inheritance rules for data types. Selecting Inherit
enables
a second menu/text box to the right. Select one of the following choices:
Inherit via internal rule
(default)
Inherit via back propagation
Same as first input
Built in
Built-in data types. Selecting Built in
enables
a second menu/text box to the right. Select one of the following choices:
double
(default)
single
int8
uint8
int16
uint16
int32
uint32
Fixed point
Fixed-point data types.
Expression
Expressions that evaluate to data types. Selecting Expression
enables
a second menu/text box to the right, where you can enter the expression.
Clicking the Show data type assistant button enables this parameter.
See Block-Specific Parameters for the command-line information.
See Specify Data Types Using Data Type Assistant.
Specify data type override mode for this signal.
Default: Inherit
Inherit
Inherits the data type override setting from its context, that
is, from the block, Simulink.Signal
object or Stateflow^{®} chart
in Simulink that is using the signal.
Off
Ignores the data type override setting of its context and uses the fixed-point data type specified for the signal.
The ability to turn off data type override for an individual data type provides greater control over the data types in your model when you apply data type override. For example, you can use this option to ensure that data types meet the requirements of downstream blocks regardless of the data type override setting.
This parameter appears only when the Mode is Built
in
or Fixed point
.
Specify whether you want the fixed-point data as signed or unsigned.
Default: Signed
Signed
Specify the fixed-point data as signed.
Unsigned
Specify the fixed-point data as unsigned.
Selecting Mode > Fixed
point
enables this parameter.
For more information, see Specifying a Fixed-Point Data Type.
Specify the bit size of the word that holds the quantized integer.
Default: 16
Minimum: 0
Maximum: 32
Selecting Mode > Fixed
point
enables this parameter.
For more information, see Specifying a Fixed-Point Data Type.
Specify the method for scaling your fixed-point data to avoid overflow conditions and minimize quantization errors.
Default: Best
precision
Binary point
Specify binary point location.
Slope and bias
Enter slope and bias.
Best precision
Specify best-precision values.
Selecting Mode > Fixed
point
enables this parameter.
Selecting Binary point
enables:
Fraction length
Calculate Best-Precision Scaling
Selecting Slope and bias
enables:
Slope
Bias
Calculate Best-Precision Scaling
For more information, see Specifying a Fixed-Point Data Type.
Specify fraction length for fixed-point data type.
Default: 0
Binary points can be positive or negative integers.
Selecting Scaling > Binary
point
enables this parameter.
For more information, see Specifying a Fixed-Point Data Type.
Specify slope for the fixed-point data type.
Default: 2^0
Specify any positive real number.
Selecting Scaling > Slope
and bias
enables this parameter.
For more information, see Specifying a Fixed-Point Data Type.
Specify bias for the fixed-point data type.
Default: 0
Specify any real number.
Selecting Scaling > Slope
and bias
enables this parameter.
For more information, see Specifying a Fixed-Point Data Type.
The following examples show the output of the Divide block for some typical inputs using default block parameter values.