Create fi object from Simulink data type

I am working on documenting a fixed point model and would like to automate as much as possible. I have a script that lists all inputs and outputs and their compiled data types (e.g. sfix27_En29). I would now like to create a fixed point object (fi()) using the data type provided from my simulink model in order to gain access to functions provided with the fixed point object.

Is there a built-in function for creating a fi() object using the Simulink data type descriptor?

Answer 1

[Andy Bartlett]

Hi

Create a numerictype object from the type name.

Then create a fi object using the numerictype as the second input argument, and the value as the first input argument.

The most general tool to create the numerictype object would be

fixed.extractNumericType

but some alternates are shown below.

See

help fixed.extractNumericType

to learn the many different inputs that can be used to create a numerictype object.

nt = fixed.extractNumericType('sfix27_En29')

nt =


          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 27
        FractionLength: 29

val3 = fi( 1/30, nt )

val3 = 
    0.0333

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 27
        FractionLength: 29

Alternates

nt2 = numerictype('sfix27_En29')

nt2 =


          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 27
        FractionLength: 29

nt3 = fixdt('sfix27_En29')

nt3 = 
  NumericType with properties:

      DataTypeMode: 'Fixed-point: binary point scaling'
        Signedness: 'Signed'
        WordLength: 27
    FractionLength: 29
           IsAlias: 0
         DataScope: 'Auto'
        HeaderFile: ''
       Description: ''

valMaxFiniteRepresentable = upperbound(nt)

valMaxFiniteRepresentable = 
    0.1250

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 27
        FractionLength: 29

valMinFiniteRepresentable = lowerbound(nt)

valMinFiniteRepresentable = 
   -0.1250

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 27
        FractionLength: 29