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coder.typeof

Create coder.Type object to represent the type of an entry-point function input

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Syntax

type_obj = coder.typeof(v)
type_obj = coder.typeof(v,sz,variable_dims)
type_obj = coder.typeof(v,'Gpu', true)
type_obj = coder.typeof(type_obj)

Description

Note

You can also create and edit coder.Type objects interactively by using the Coder Type Editor. See Create and Edit Input Types by Using the Coder Type Editor.

type_obj = coder.typeof(v) creates an object that is derived from coder.Type to represent the type of v for code generation. Use coder.typeof to specify only input parameter types. Use it with the codegen function -args option or in a MATLAB® Coder™ project when you are defining an input type by providing a sample code. Do not use it in MATLAB code from which you intend to generate code.

example

type_obj = coder.typeof(v,sz,variable_dims) returns a modified copy of type_obj = coder.typeof(v) with upper bound size specified by sz and variable dimensions specified by variable_dims.

example

type_obj = coder.typeof(v,'Gpu', true) creates an object that is derived from coder.Type to represent v as a GPU input type for code generation. This option requires a valid GPU Coder™ license.

type_obj = coder.typeof(type_obj) returns type_obj itself.

example

Examples

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Create a type for a simple fixed-size 5x6 matrix of doubles.

coder.typeof(ones(5,6))
ans = 

coder.PrimitiveType
   5×6 double

coder.typeof(0,[5 6])
ans = 

coder.PrimitiveType
   5×6 double

Create a type for a variable-size matrix of doubles.

coder.typeof(ones(3,3),[],1)
ans = 

coder.PrimitiveType
   :3×:3 double
% ':' indicates variable-size dimensions

Create a type for a matrix with fixed-size and variable-size dimensions.

coder.typeof(0,[2,3,4],[1 0 1])

ans = 

coder.PrimitiveType
   :2×3×:4 double


coder.typeof(10,[1 5],1) 

ans = 

coder.PrimitiveType
   1×:5 double
% ':' indicates variable-size dimensions

Create a type for a matrix of doubles, first dimension unbounded, second dimension with fixed size.

coder.typeof(10,[inf,3]) 

ans = 

coder.PrimitiveType
   :inf×3 double
% ':' indicates variable-size dimensions

Create a type for a matrix of doubles, first dimension unbounded, second dimension with variable size that has an upper bound of 3.

coder.typeof(10,[inf,3],[0 1]) 

ans = 

coder.PrimitiveType
   :inf×:3 double

Convert a fixed-size matrix to a variable-size matrix.

coder.typeof(ones(5,5),[],1) 

 ans = 

coder.PrimitiveType
   :5×:5 double
% ':' indicates variable-size dimensions

Create a type for a structure with a variable-size field.

x.a = coder.typeof(0,[3 5],1);
x.b = magic(3);
coder.typeof(x)

ans = 

coder.StructType
   1×1 struct
      a: :3×:5 double
      b: 3×3 double
% ':' indicates variable-size dimensions

Create a nested structure (a structure as a field of another structure).

S = struct('a',double(0),'b',single(0));
SuperS.x = coder.typeof(S);
SuperS.y = single(0);
coder.typeof(SuperS)  

ans = 

coder.StructType
   1×1 struct
      x: 1×1 struct
         a: 1×1 double
         b: 1×1 single
      y: 1×1 single

Create a structure containing a variable-size array of structures as a field.

S = struct('a',double(0),'b',single(0));
SuperS.x = coder.typeof(S,[1 inf],[0 1]);
SuperS.y = single(0);
coder.typeof(SuperS)
ans = 

coder.StructType
   1×1 struct
      x: 1×:inf struct
         a: 1×1 double
         b: 1×1 single
      y: 1×1 single
% ':' indicates variable-size dimensions

Create a type for a homogeneous cell array with a variable-size field.

a = coder.typeof(0,[3 5],1);
b = magic(3);
coder.typeof({a b})
ans = 

coder.CellType
   1×2 homogeneous cell 
      base: :3×:5 double
% ':' indicates variable-size dimensions

Create a type for a heterogeneous cell array.

a = coder.typeof('a');
b = coder.typeof(1);
coder.typeof({a b})
ans = 

coder.CellType
   1×2 heterogeneous cell 
      f1: 1×1 char
      f2: 1×1 double

Create a variable-size homogeneous cell array type from a cell array that has the same class but different sizes.

1. Create a type for a cell array that contains two character vectors with different sizes. The cell array type is heterogeneous.

coder.typeof({'aa','bbb'})
ans = 

coder.CellType
   1×2 heterogeneous cell 
      f1: 1×2 char
      f2: 1×3 char

2. Create a type by using the same cell array input. This time, specify that the cell array type has variable-size dimensions. The cell array type is homogeneous.

coder.typeof({'aa','bbb'},[1,10],[0,1])

ans = 

coder.CellType
   1×:10 locked homogeneous cell 
      base: 1×:3 char
% ':' indicates variable-size dimensions

Change a fixed-size array to a bounded, variable-size array.

Create a type for a value class object.

1. Create this value class:

classdef mySquare
    properties
        side;
    end
    methods
        function obj = mySquare(val)
            if nargin > 0
                obj.side = val;
            end
        end
        function a = calcarea(obj)
            a = obj.side * obj.side;
        end
    end
end

2. Create an object of mySquare.

sq_obj = coder.typeof(mySquare(4))
sq_obj = 

coder.ClassType
   1×1 mySquare   
      side: 1×1 double

3. Create a type for an object that has the same properties as sq_obj.

t = coder.typeof(sq_obj)
t = 

coder.ClassType
   1×1 mySquare   
      side: 1×1 double

Alternatively, you can create the type from the class definition:

t = coder.typeof(mySquare(4))
t = 

coder.ClassType
   1×1 mySquare   
      side: 1×1 double

Define a string scalar. For example:

s = "mystring";

Create a type from s.

t = coder.typeof(s);

Assign the StringLength property of the type object the upper bound of the string length and set VariableStringLength to true. Specify that type object t is variable-size with an upper bound of 10.

t.StringLength = 10;
t.VariableStringLength = true;

To specify that t is variable-size without an upper bound:

t.StringLength = Inf;
This automatically sets the VariableStringLength property to true.

Pass the type to codegen by using the -args option.

codegen myFunction -args {t}

Input Arguments

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v can be a MATLAB numeric, logical, char, enumeration, or fixed-point array. v can also be a cell array, structure, or value class that contains the previous types.

When v is a cell array whose elements have the same classes but different sizes, if you specify variable-size dimensions, coder.typeof creates a homogeneous cell array type. If the elements have different classes, coder.typeof reports an error.

Example: coder.typeof(ones(5,6));

Data Types: half | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | string | struct | table | cell | function_handle | categorical | datetime | duration | calendarDuration | fi
Complex Number Support: Yes

Size vector specifying each dimension of type object.

If sz specifies inf for a dimension, then the size of the dimension is unbounded and the dimension is variable size. When sz is [], the upper bounds of v do not change.

If size is not specified, sz takes the default dimension of v.

Example: coder.typeof(0,[5,6]);

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

Logical vector that specifies whether each dimension is variable size (true) or fixed size (false). For a cell array, if the elements have different classes, you cannot specify variable-size dimensions.

If you do not specify the variable_dims input parameter, the bounded dimensions of the type are fixed.

A scalar variable_dims applies to all dimensions. However, if variable_dims is 1, the size of a singleton dimension remains fixed.

Example: coder.typeof(0,[2,3,4],[1 0 1]);

Data Types: logical

coder.Type object to represent the type of v for code generation.

Example: type_obj = coder.typeof(ones(5,6));

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | string | struct | table | cell | function_handle | categorical | datetime | duration | calendarDuration | fi
Complex Number Support: Yes

Output Arguments

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coder.Type object to represent the type of v for code generation.

Example: type_obj = coder.typeof(ones(5,6));

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | string | struct | table | cell | function_handle | categorical | datetime | duration | calendarDuration | fi
Complex Number Support: Yes

Limitations

  • For sparse matrices, coder.typeof drops upper bounds for variable-size dimensions.

  • Scalar GPU arrays, structures, cell-arrays, classes, enumerated types, character, half-precision and fixed-point data types are not supported.

  • When using coder.typeof to represent GPU arrays, the memory allocation (malloc) mode property of the GPU code configuration object must be set to be 'discrete'.

  • You cannot pass an unconfigured dictionary to coder.typeof.

Tips

  • coder.typeof fixes the size of a singleton dimension unless the variable_dims argument explicitly specifies that the singleton dimension has a variable size.

    For example, the following code specifies a 1-by-:10 double. The first dimension (the singleton dimension) has a fixed size. The second dimension has a variable size.

    t = coder.typeof(5,[1 10],1)
    By contrast, this code specifies a :1-by-:10 double. Both dimensions have a variable size.
    t = coder.typeof(5,[1 10],[1 1])

    Note

    For a MATLAB Function block, singleton dimensions of input or output signals cannot have a variable size.

  • If you are already specifying the type of an input variable by using a type function, do not use coder.typeof unless you also want to specify the size. For instance, instead of coder.typeof(single(0)), use the syntax single(0).

  • For cell array types, coder.typeof determines whether the cell array type is homogeneous or heterogeneous.

    If the cell array elements have the same class and size, coder.typeof returns a homogeneous cell array type.

    If the elements have different classes, coder.typeof returns a heterogeneous cell array type.

    For some cell arrays, classification as homogeneous or heterogeneous is ambiguous. For example, the type for {1 [2 3]} can be a 1x2 heterogeneous type where the first element is double and the second element is 1x2 double. The type can also be a 1x3 homogeneous type in which the elements have class double and size 1x:2. For these ambiguous cases, coder.typeof uses heuristics to classify the type as homogeneous or heterogeneous. If you want a different classification, use the coder.CellType makeHomogeneous or makeHeterogeneous methods to make a type with the classification that you want. The makeHomogeneous method makes a homogeneous copy of a type. The makeHeterogeneous method makes a heterogeneous copy of a type.

    The makeHomogeneous and makeHeterogeneous methods permanently assign the classification as heterogeneous and homogeneous. You cannot later use one of these methods to create a copy that has a different classification.

  • You can use coder.typeof to create an unbounded GPU array input and pass it to the entry-point functions. For example, create a GPU input using coder.typeof(int32(1),[inf,1],'Gpu',true).

  • During code generation with GPU array types, if one input to the entry-point function is of the GPU array type, then the output variables are all GPU array types, provided they are supported for GPU code generation. For example. if the entry-point function returns a struct and because struct is not supported, the generated code returns a CPU output. However, if a supported matrix type is returned, then the generated code returns a GPU output.

Version History

Introduced in R2011a

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See Also

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