# fixdt

Create Simulink.NumericType object describing a fixed-point or floating-point data type

## Description

example

a = fixdt(Signed,WordLength) returns a Simulink.NumericType object that describes a fixed-point data type with the specified signedness and word length, and unspecified scaling.

example

a = fixdt(Signed,WordLength,FractionLength) returns a Simulink.NumericType object that describes a fixed-point data type with binary point scaling.

example

a = fixdt(Signed,WordLength,TotalSlope,Bias) returns a Simulink.NumericType object that describes a fixed-point data type with slope and bias scaling.

example

a = fixdt(Signed,WordLength,SlopeAdjustmentFactor,FixedExponent,Bias) returns a Simulink.NumericType object that describes a fixed-point data type with slope and bias scaling.

example

a = fixdt(DataTypeNameString) returns a Simulink.NumericType object that describes an integer, fixed-point, or floating-point data type specified by the name of a data type.

example

a = fixdt(___,'DataTypeOverride','Off') returns a Simulink.NumericType object with its DataTypeOverride parameter set to Off. The default value for this property is Inherit. You can specify the DataTypeOverride parameter after any combination of other input parameters.

example

[a,IsScaledDouble] = fixdt(___) returns a Simulink.NumericType object that describes a fixed-point or floating-point data type and a flag that indicates whether the specified data type is of a scaled double data type.

## Examples

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Create a signed Simulink.NumericType object with a word length of 16 bits and unspecified scaling.

a = fixdt(1,16)
a =
NumericType with properties:

DataTypeMode: 'Fixed-point: unspecified scaling'
Signedness: 'Signed'
WordLength: 16
IsAlias: 0
DataScope: 'Auto'
Description: ''

Create a Simulink.NumericType object that describes a signed fixed-point data types with a word length of 16 bits and fraction length of 2 bits.

a = fixdt(1,16,2)
a =
NumericType with properties:

DataTypeMode: 'Fixed-point: binary point scaling'
Signedness: 'Signed'
WordLength: 16
FractionLength: 2
IsAlias: 0
DataScope: 'Auto'
Description: ''

The real-world value of a slope bias scaled number is represented by:

$\mathrm{real}\text{\hspace{0.17em}}\mathrm{world}\text{\hspace{0.17em}}\mathrm{value}=\left(\mathrm{slope}×\mathrm{integer}\right)+\mathrm{bias}$

Create a Simulink.NumericType object that describes a signed fixed-point data type with a word length of 16 bits, slope of 2^-2, and bias of 4.

a = fixdt(1,16,2^-2,4)
a =
NumericType with properties:

DataTypeMode: 'Fixed-point: slope and bias scaling'
Signedness: 'Signed'
WordLength: 16
Slope: 0.2500
Bias: 4
IsAlias: 0
DataScope: 'Auto'
Description: ''

Alternatively, the slope can by represented by:

$\mathrm{slope}=\mathrm{slopeadjustmentfactor}×{2}^{\mathrm{fixedexponent}}$

a = fixdt(1,16,1,-2,4)
a =
NumericType with properties:

DataTypeMode: 'Fixed-point: slope and bias scaling'
Signedness: 'Signed'
WordLength: 16
Slope: 0.2500
Bias: 4
IsAlias: 0
DataScope: 'Auto'
Description: ''

The DataTypeMode property of the Simulink.NumericType object, a, is slope and bias scaling.

Use a data type name to create a Simulink.NumericType object that describes an 8-bit, unsigned, fixed-point data type and return a flag that indicates whether the object is of a scaled double data type.

[a,IsScaledDouble] = fixdt('ufix8')
a =
NumericType with properties:

DataTypeMode: 'Fixed-point: binary point scaling'
Signedness: 'Unsigned'
WordLength: 8
FractionLength: 0
IsAlias: 0
DataScope: 'Auto'
Description: ''

IsScaledDouble = logical
0

The IsScaledDouble output returns 0, which indicates that the data type of a is not a scaled double data type.

Create a Simulink.NumericType object with its DataTypeOverride property set to Off.

a = fixdt(0,8,2,'DataTypeOverride','Off')
a =
NumericType with properties:

DataTypeMode: 'Fixed-point: binary point scaling'
Signedness: 'Unsigned'
WordLength: 8
FractionLength: 2
DataTypeOverride: 'Off'
IsAlias: 0
DataScope: 'Auto'
Description: ''

## Input Arguments

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Signedness of the Simulink.NumericType object, specified as a numeric or logical 1 (true) or 0 (false). A value of 1, or true, indicates a signed data type. A value of 0, or false, indicates an unsigned data type.

Data Types: logical

Word length, in bits, of the Simulink.NumericType object, specified as a positive scalar.

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Fraction length, in bits, of the Simulink.NumericType object, specified as a scalar.

FractionLength can be greater than WordLength. For more information, see Binary Point Interpretation (Fixed-Point Designer).

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Slope of the scaling, specified as a scalar.

The following equation represents the real-world value of a slope bias scaled number:

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Bias of the scaling, specified as a scalar.

The following equation represents the real-world value of a slope bias scaled number:

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Slope adjustment factor of a slope bias scaled number, 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, fixdt 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 following equation demonstrates the relationship between the slope, fixed exponent, and slope adjustment factor:

$slope=slopeadjustmentfactor×{2}^{fixedexponent}$

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Fixed exponent of a slope bias scaled number, specified as a scalar.

The following equation demonstrates the relationship between the slope, fixed exponent, and slope adjustment factor:

$slope=slopeadjustmentfactor×{2}^{fixedexponent}$

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Data type name, specified as a character vector.

The data type name can be either the name of a built-in Simulink® data type or the name of a fixed-point data type that conforms to the naming convention for fixed-point names established by the Fixed-Point Designer™ product. For more information, see Fixed-Point Data Type and Scaling Notation (Fixed-Point Designer).

Data Types: char

## Output Arguments

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Data type, returned as a Simulink.NumericType object.

Scaled double flag, returned as a logical that indicates whether the specified data type name is the name of a scaled double data type.

## Version History

Introduced before R2006a