Sizing Function Arguments

Specifying Argument Size

To examine or specify the size of an argument, follow these steps:

1. From the Embedded MATLAB Editor, select Model Explorer or Tools > Edit Data/Ports.

2. In the Contents pane, click the row that contains the data argument.

3. Enter the size of the argument in one of two places:

   • Size field of the Data properties dialog, located in the Dialog pane

   • Size column in the row that contains the data argument, located in the Contents pane

   Note   The default value is -1, indicating that size is inherited, as described in Inheriting Argument Sizes from Simulink.

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Inheriting Argument Sizes from Simulink

Size defaults to -1, which means that the data argument inherits its size from Simulink based on its scope:

After you compile the model, the Compiled Size column in the Contents pane displays the actual size used in the compiled simulation application:

The size of an output argument is the size of the value that is assigned to it. If the expected size in the Simulink model does not match, a mismatch error occurs during compilation of the model.

Note   No arguments with inherited sizes are allowed for Embedded MATLAB Function blocks in a library.

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Specifying Argument Sizes with Expressions

The size of a data argument can be a scalar value or a MATLAB vector of values.

To specify size as a scalar, set the Size field to 1 or leave it blank. To specify Size as a vector, enter an array of up to two dimensions in [row column] format where

• The number of dimensions equals the length of the vector.

• The size of each dimension corresponds to the value of each element of the vector.

For example, a value of [2 4] defines a 2-by-4 matrix. To define a row vector of size 5, set the Size field to [1 5]. To define a column vector of size 6, set the Size field to [6 1] or just 6. You can enter a MATLAB expression for each [row column] element in the Size field. Each expression can use one or more of the following elements:

• Numeric constants

• Arithmetic operators, restricted to +, -, *, and /

• Parameters defined in the MATLAB Workspace or the parent Simulink masked subsystem

• Calls to the MATLAB functions min, max, and size

The following examples are valid expressions for Size:

k+1
size(x)
min(size(y),k)

In these examples, k, x, and y are variables of scope Parameter.

Once you build the model, the Compiled Size column in the Contents pane displays the actual size used in the compiled simulation application.

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Typing Function Arguments

Parameter Arguments in Embedded MATLAB Functions

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• Simulink
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• Physical Modeling
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