numerictype
Construct an embedded.numerictype
object describing fixed-point
or floating-point data type
Syntax
Description
T = numerictype
creates a default numerictype
object.
T = numerictype(
creates a fixed-point
s
)numerictype
object with unspecified scaling, a signed property value of
s
, and a 16-bit word length.
T = numerictype(
creates a fixed-point s
,w
,slopeadjustmentfactor
,fixedexponent
,bias
)numerictype
object with slope and bias scaling, a
signed property value of s
, word length of w
,
slopeadjustmentfactor
, and bias
.
T = numerictype(___,
allows you to set properties using name-value pairs. All properties that you do not specify
a value for are assigned their default values.Name,Value
)
T = numerictype(T1,
allows you to
make a copy, Name,Value
)T1
, of an existing numerictype
object,
T
, while modifying any or all of the property values.
T = numerictype('Double')
creates a numerictype
object of data type double.
T = numerictype('Single')
creates a numerictype
object of data type single.
T = numerictype('Half')
creates a numerictype
object of data type half.
T = numerictype('Boolean')
creates a numerictype
object of data type Boolean.
Examples
Create a Default numerictype
Object
This example shows how to create a numerictype
object with default property settings.
T = numerictype
T = DataTypeMode: Fixed-point: binary point scaling Signedness: Signed WordLength: 16 FractionLength: 15
Create a numerictype
Object with Default Word Length and Scaling
This example shows how to create a numerictype
object with the default word length and scaling by omitting the arguments for word length, w
, and fraction length, f
.
T = numerictype(1)
T = DataTypeMode: Fixed-point: unspecified scaling Signedness: Signed WordLength: 16
The object is signed, with a word length of 16 bits and unspecified scaling.
You can use the signedness argument, s
, to create an unsigned numerictype
object.
T = numerictype(0)
T = DataTypeMode: Fixed-point: unspecified scaling Signedness: Unsigned WordLength: 16
The object is has the default word length of 16 bits and unspecified scaling.
Create a numerictype
Object with Unspecified Scaling
This example shows how to create a numerictype
object with unspecified scaling by omitting the fraction length argument, f
.
T = numerictype(1,32)
T = DataTypeMode: Fixed-point: unspecified scaling Signedness: Signed WordLength: 32
The object is signed, with a 32-bit word length.
Create a numerictype
Object with Specified Word and Fraction Length
This example shows how to create a signed numerictype
object with binary-point scaling, a 32-bit word length, and 30-bit fraction length.
T = numerictype(1,32,30)
T = DataTypeMode: Fixed-point: binary point scaling Signedness: Signed WordLength: 32 FractionLength: 30
Create a numerictype
Object with Slope and Bias Scaling
This example shows how to create a numerictype
object with slope and bias scaling. The real-world value of a slope and bias scaled number is represented by:
Create a numerictype
object that describes a signed, fixed-point data type with a word length of 16 bits, a slope of 2^-2, and a bias of 4.
T = numerictype(1,16,2^-2,4)
T = DataTypeMode: Fixed-point: slope and bias scaling Signedness: Signed WordLength: 16 Slope: 0.25 Bias: 4
Alternatively, the slope can be represented by:
Create a numerictype
object that describes a signed, fixed-point data type with a word length of 16 bits, a slope adjustment factor of 1, a fixed exponent of -2, and a bias of 4.
T = numerictype(1,16,1,-2,4)
T = DataTypeMode: Fixed-point: slope and bias scaling Signedness: Signed WordLength: 16 Slope: 0.25 Bias: 4
Create a numerictype
Object with Specified Property Values
This example shows how to use name-value pairs to set numerictype
properties at object creation.
T = numerictype('Signed',true,... 'DataTypeMode',... 'Fixed-point: slope and bias scaling', ... 'WordLength',32,... 'Slope',2^-2,... 'Bias',4)
T = DataTypeMode: Fixed-point: slope and bias scaling Signedness: Signed WordLength: 32 Slope: 0.25 Bias: 4
Create a numerictype
Object with Unspecified Sign
This example shows how to create a numerictype
object with an unspecified sign by using name-value pairs to set the Signedness
property to Auto
.
T = numerictype('Signedness','Auto')
T = DataTypeMode: Fixed-point: binary point scaling Signedness: Auto WordLength: 16 FractionLength: 15
Create a numerictype
Object with Specified Data Type
This example shows how to create a numerictype
object with a specific data type by using arguments and name-value pairs.
T = numerictype(0,24,12,'DataType','ScaledDouble')
T = DataTypeMode: Scaled double: binary point scaling Signedness: Unsigned WordLength: 24 FractionLength: 12
The returned numerictype
object, T
, is unsigned, and has a word length of 24 bits, a fraction length of 12 bits, and a data type set to scaled double.
Create a Double, Single, Half, or Boolean numerictype
Object
This example shows how to create a numerictype
object with data type set to double, single, half, or Boolean at object creation.
Create a numerictype
object with the data type mode set to double.
T = numerictype('Double')
T = DataTypeMode: Double
Create a numerictype
object with the data type mode set to single.
T = numerictype('Single')
T = DataTypeMode: Single
Create a numerictype
object with the data type mode set to half.
T = numerictype('Half')
T = DataTypeMode: Half
Create a numerictype
object with the data type mode set to Boolean.
T = numerictype('Boolean')
T = DataTypeMode: Boolean
Input Arguments
s
— Whether object is signed
true
or 1
(default) | false
or 0
Whether the object is signed, specified as a numeric or logical 1
(true
) or 0
(false
).
Example: T = numerictype(true)
Data Types: logical
w
— Word length
16
(default) | positive integer
Word length, in bits, of the stored integer value, specified as a positive integer.
Example: T = numerictype(true,16)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
f
— Fraction length
15
(default) | integer
Fraction length, in bits, of the stored integer value, specified as an integer.
Fraction length can be greater than word length. For more information, see Binary Point Interpretation (Fixed-Point Designer).
Example: T = numerictype(true,16,15)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
slope
— Slope
3.0518e-05
(default) | finite floating-point number greater than zero
Slope, specified as a finite floating-point number greater than zero.
The slope and the bias determine the scaling of a fixed-point number.
Note
Changing one of these properties affects the others.
Example: T = numerictype(true,16,2^-2,4)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
bias
— Bias associated with object
0
(default) | floating-point number
Bias associated with the object, specified as a floating-point number.
The slope and the bias determine the scaling of a fixed-point number.
Example: T = numerictype(true,16,2^-2,4)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
slopeadjustmentfactor
— Slope adjustment factor
1
(default) | positive scalar
Slope adjustment factor, specified as a positive scalar.
The slope adjustment factor must be greater than or equal to 1 and less than 2. If
you input a slopeadjustmentfactor
outside this range, the
numerictype
object automatically applies a scaling normalization to
the values of slopeadjustmentfactor
and
fixedexponent
so that the revised slope adjustment factor is
greater than or equal to 1 and less than 2, and maintains the value of the slope.
The slope adjustment is equivalent to the fractional slope of a fixed-point number.
Note
Changing one of these properties affects the others.
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
fixedexponent
— Fixed-point exponent
-15
(default) | integer
Fixed-point exponent associated with the object, specified as an integer.
Note
The FixedExponent
property is the negative of the
FractionLength
. Changing one property changes the other.
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Before R2021a, use commas to separate each name and value, and enclose
Name
in quotes.
Example: F = numerictype('DataTypeMode','Fixed-point: binary point
scaling','DataTypeOverride','Inherit')
Note
When you create a numerictype
object by using name-value pairs,
Fixed-Point Designer™ creates a default numerictype
object, and then, for each
property name you specify in the constructor, assigns the corresponding value. This
behavior differs from the behavior that occurs when you use a syntax such as T =
numerictype(s,w)
. See Example: Construct a numerictype Object with Property Name and Property Value Pairs.
Bias
— Bias
0
(default) | floating-point number
Bias, specified as a floating-point number.
The slope and bias determine the scaling of a fixed-point number.
Example: T = numerictype('DataTypeMode','Fixed-point: slope and bias
scaling','Bias',4)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
DataType
— Data type category
'Fixed'
(default) | 'Boolean'
| 'Double'
| 'ScaledDouble'
| 'Single'
| 'Half'
Data type category, specified as one of these values:
'Fixed'
– Fixed-point or integer data type'Boolean'
– Built-in MATLAB® Boolean data type'Double'
– Built-in MATLAB double data type'ScaledDouble'
– Scaled double data type'Single'
– Built-in MATLAB single data type'Half'
– MATLAB half-precision data type
Example: T = numerictype('Double')
Data Types: char
DataTypeMode
— Data type and scaling mode
'Fixed-point: binary point scaling'
(default) | 'Fixed-point: slope and bias scaling'
| 'Fixed-point: unspecified scaling'
| 'Scaled double: binary point scaling'
| 'Scaled double: slope and bias scaling'
| 'Scaled double: unspecified scaling'
| 'Double'
| 'Single'
| 'Half'
| 'Boolean'
Data type and scaling mode associated with the object, specified as one of these values:
'Fixed-point: binary point scaling'
– Fixed-point data type and scaling defined by the word length and fraction length'Fixed-point: slope and bias scaling'
– Fixed-point data type and scaling defined by the slope and bias'Fixed-point: unspecified scaling'
– Fixed-point data type with unspecified scaling'Scaled double: binary point scaling'
– Double data type with fixed-point word length and fraction length information retained'Scaled double: slope and bias scaling'
– Double data type with fixed-point slope and bias information retained'Scaled double: unspecified scaling'
– Double data type with unspecified fixed-point scaling'Double'
– Built-indouble
'Single'
– Built-insingle
'Half'
– MATLAB half-precision data type'Boolean'
– Built-inboolean
Example: T = numerictype('DataTypeMode','Fixed-point: binary point
scaling')
Data Types: char
DataTypeOverride
— Data type override settings
'Inherit' (default) | 'Off'
Data type override settings, specified as one of these values:
'Inherit'
– Turn onDataTypeOverride
'Off'
– Turn offDataTypeOverride
Note
The DataTypeOverride
property is not visible when its value
is set to the default, 'Inherit'
.
Example: T =
numerictype('DataTypeOverride','Off')
Data Types: char
FixedExponent
— Fixed-point exponent
-15
(default) | integer
Fixed-point exponent associated with the object, specified as an integer.
Note
The FixedExponent
property is the negative of the
FractionLength
. Changing one property changes the other.
Example: T = numerictype('FixedExponent',-12)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
FractionLength
— Fraction length of the stored integer value
best precision (default) | integer
Fraction length, in bits, of the stored integer value, specified as an integer.
The default value is the best precision fraction length based on the value of the object and the word length.
Example: T = numerictype('FractionLength',12)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
Scaling
— Fixed-point scaling mode
'BinaryPoint'
(default) | 'SlopeBias'
| 'Unspecified'
Fixed-point scaling mode of the object, specified as one of these values:
'BinaryPoint'
– Scaling for thenumerictype
object is defined by the fraction length.'SlopeBias'
– Scaling for thenumerictype
object is defined by the slope and bias.'Unspecified'
– Temporary setting that is only allowed atnumerictype
object creation, and allows for the automatic assignment of a best-precision binary point scaling.
Example: T = numerictype('Scaling','BinaryPoint')
Data Types: char
Signed
— Whether the object is signed
true
or 1
(default) | false
or 0
Whether the object is signed, specified as a numeric or logical
1
(true
) or 0
(false
).
Note
Although the Signed
property is still supported, the
Signedness
property always appears in the
numerictype
object display. If you choose to change or set the
signedness of your numerictype
object using the
Signed
property, MATLAB updates the corresponding value of the Signedness
property.
Example: T = numerictype('Signed',true)
Data Types: logical
Signedness
— Whether the object is signed
'Signed'
(default) | 'Unsigned'
| 'Auto'
Whether the object is signed, specified as one of these values:
'Signed'
– Signed'Unsigned'
– Unsigned'Auto'
– Unspecified sign
Note
Although you can create numerictype
objects with an
unspecified sign (Signedness: Auto
), all fixed-point
numerictype
objects must have a Signedness
of Signed
or Unsigned
. If you use a
numerictype
object with Signedness: Auto
to
construct a numerictype
object, the Signedness
property of the numerictype
object automatically defaults to
Signed
.
Example: T = numerictype('Signedness','Signed')
Data Types: char
Slope
— Slope
3.0518e-05
(default) | finite, positive floating-point number
Slope, specified as a finite, positive floating-point number.
The slope and bias determine the scaling of a fixed-point number.
Note
Changing one of these properties affects the others.
Example: T = numerictype('DataTypeMode','Fixed-point: slope and bias
scaling','Slope',2^-2)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
SlopeAdjustmentFactor
— Slope adjustment factor
1
(default) | positive scalar
Slope adjustment factor, specified as a positive scalar.
The slope adjustment factor must be greater than or equal to 1 and less than 2. If
you input a slopeadjustmentfactor
outside this range, the
numerictype
object automatically applies a scaling normalization
to the values of slopeadjustmentfactor
and
fixedexponent
so that the revised slope adjustment factor is
greater than or equal to 1 and less than 2, and maintains the value of the
slope.
The slope adjustment is equivalent to the fractional slope of a fixed-point number.
Note
Changing one of these properties affects the others.
Example: T = numerictype('DataTypeMode','Fixed-point: slope and bias
scaling','SlopeAdjustmentFactor',1.5)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
WordLength
— Word length of the stored integer value
16
(default) | positive integer
Word length, in bits, of the stored integer value, specified as a positive integer.
Example: T = numerictype('WordLength',16)
Data Types: half
| single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Usage notes and limitations:
Fixed-point signals coming in to a MATLAB Function block from Simulink® are assigned a
numerictype
object that is populated with the signal's data type and scaling information.Returns the data type when the input is a non fixed-point signal.
Use to create
numerictype
objects in generated code.All
numerictype
object properties related to the data type must be constant.
HDL Code Generation
Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.
Version History
Introduced before R2006aR2021a: Inexact property names for fi
, fimath
, and
numerictype
objects not supported
In previous releases, inexact property names for fi
,
fimath
, and numerictype
objects would result in a
warning. In R2021a, support for inexact property names was removed. Use exact property names
instead.
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