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fimath Object Construction

fimath Object Syntaxes

The arithmetic attributes of a fi object are defined by a local fimath object, which is attached to that fi object. If a fi object has no local fimath, the following default fimath values are used:

        RoundingMethod: Nearest
        OverflowAction: Wrap
           ProductMode: FullPrecision
               SumMode: FullPrecision

You can create fimath objects in Fixed-Point Designer™ software in one of two ways:

  • You can use the fimath constructor function to create new fimath objects.

  • You can use the fimath constructor function to copy an existing fimath object.

To get started, type

F = fimath

to create a fimath object.

F = 

        RoundingMethod: Nearest
        OverflowAction: Saturate
           ProductMode: FullPrecision
               SumMode: FullPrecision

To copy a fimath object, simply use assignment as in the following example:

F = fimath;
G = F;
ans =



The syntax

F = fimath(...'PropertyName',PropertyValue...)

allows you to set properties for a fimath object at object creation with property name/property value pairs. Refer to Setting fimath Properties at Object Creation.

Building fimath Object Constructors in a GUI

When you are working with files in MATLAB®, you can build your fimath object constructors using the Insert fimath Constructor dialog box. After specifying the properties of the fimath object in the dialog box, you can insert the prepopulated fimath object constructor at a specific location in your file.

For example, to create a fimath object that uses convergent rounding and wraps on overflow, perform the following steps:

  1. On the Home tab, in the File section, click New > Script to open the MATLAB Editor

  2. On the Editor tab, in the Edit section, click in the Insert button group. Click the Insert fimath... to open the Insert fimath Constructor dialog box.

  3. Use the edit boxes and drop-down menus to specify the following properties of the fimath object:

    • Rounding method = Floor

    • Overflow action = Wrap

    • Product mode = FullPrecision

    • Sum mode = FullPrecision

  4. To insert the fimath object constructor in your file, place your cursor at the desired location in the file. Then click OK on the Insert fimath Constructor dialog box. Clicking OK closes the Insert fimath Constructor dialog box and automatically populates the fimath object constructor in your file: