Specify Objects as Inputs

When you accelerate code by using fiaccel, to specify the type of an input that is a value class object, you can provide an example object with the -args option.

1. Define the value class. For example, define a class myRectangle.

   classdef myRectangle
       properties
           length;
           width;
       end
       methods
           function obj = myRectangle(l,w)
               if nargin > 0
                   obj.length = l;
                   obj.width = w;
               end
           end
           function area = calcarea(obj)
               area = obj.length * obj.width;
           end
       end
   end

2. Define a function that takes an object of the value class as an input. For example:

   function z = getarea(r)
   %#codegen
   z = calcarea(r);
   end

3. Define an object of the class.

   rect_obj = myRectangle(fi(4),fi(5))
   

   rect_obj = 
   
     myRectangle with properties:
   
       length: [1×1 embedded.fi]
        width: [1×1 embedded.fi]

4. Pass the example object to fiaccel by using the -args option.

   fiaccel getarea -args {rect_obj} -report

   In the report, you see that r has the same properties, length and width, as the example object rect_object.

   

Instead of providing an example object, you can create a type for an object of the value class and provide the type with the -args option.

1. Define an object of the class:

   rect_obj = myRectangle(fi(4),fi(5))

   rect_obj = 
   
     myRectangle with properties:
   
       length: [1×1 embedded.fi]
        width: [1×1 embedded.fi]

2. To create a type for an object of myRectangle that has the same property types as rect_obj, use coder.typeof. coder.typeof creates a coder.ClassType object that defines a type for a class.

   t= coder.typeof(rect_obj)
   

   t = 
   
   coder.ClassType
      1×1 myRectangle   
         length: 1×1 embedded.fi
                   DataTypeMode: Fixed-point: binary point scaling
                     Signedness: Signed
                     WordLength: 16
                 FractionLength: 12
         
         width : 1×1 embedded.fi
                   DataTypeMode: Fixed-point: binary point scaling
                     Signedness: Signed
                     WordLength: 16
                 FractionLength: 12

3. Pass the type to fiaccel by using the -args option.

   fiaccel getarea -args {t} -report

After you create the type, you can change the types of the properties.

t.Properties.length = coder.typeof(fi(0,1,32,29))
t.Properties.width = coder.typeof(fi(0,1,32,29))

You can also add or delete properties. For example, to add a property newprop:

t.Properties.newprop = coder.typeof(int16(1))

Consistency Between coder.ClassType Object and Class Definition File

When you accelerate code, the properties of the coder.ClassType object that you pass to fiaccel must be consistent with the properties in the class definition file. If the class definition file has properties that your code does not use, the coder.ClassType object does not have to include those properties. fiaccel removes properties that you do not use.

Limitations for Using Objects as Entry-Point Function Inputs

Entry-point function inputs that are objects have these limitations:

• An object that is an entry-point function input must be an object of a value class. Objects of handle classes cannot be entry-point function inputs. Therefore, a value class that contains a handle class cannot be an entry-point function input.

• An object cannot be a global variable.

• If an object has duplicate property names, you cannot use it with coder.Constant. Duplicate property names occur in an object of a subclass in these situations:

  • The subclass has a property with the same name as a property of the superclass.

  • The subclass derives from multiple superclasses that use the same name for a property.

  For information about when MATLAB^® allows duplicate property names, see Subclassing Multiple Classes.