By default, the generated code contains one-dimensional arrays for multidimensional model
data. In the Configuration Parameters dialog box, if you set the Array layout parameter to
Row-major, you can preserve dimensions of multidimensional
arrays in the generated code. Preserving array dimensions in the generated code enhances
integration with external code.
MATLAB® and C organize multidimensional data in different ways. For more details, see Dimension Preservation of Multidimensional Arrays.
In the generated code, you can preserve dimensions of root-level inports and outports, parameters, signals, states, lookup tables, and data stores.
In the Code Mappings > Data Defaults tab, you can configure these model data elements categories. You specify a storage class to preserve dimensions.
Signals, states, and internal data
Shared local data stores
Global data stores
Then, when you set the Storage class to
Model default on
individual model data elements, by default, the code generator applies the configuration
that you set up for the respective model data elements in the Data
An example workflow that is applicable to the preceding model data element categories is:
Open the model
In the Configuration Parameters dialog box, verify that parameter
Array layout is set to
Open the Embedded Coder app.
In the C Code tab, open the Code Mappings editor. Select Code Interface > Default Code Mappings. This option pins the Code Mappings editor and the Property Inspector pane.
On the Data Defaults tab, select the
Inports category. The Storage
Class specified is
the Property Inspector, in the Code section, select the
To configure the PreserveDimensions property
programmatically, use the
coder.mapping.defaults.set function in the MATLAB command
coder.mapping.defaults.set('rtwdemo_preservedimensions', 'Inports',... 'Storageclass', 'ExportToFile',... 'PreserveDimensions', 'off')
You can create a new storage class in Embedded Coder®, and then specify that class to preserve dimensions. For more details, see Preserve Dimensions for New Storage Classes.
For a list of supported storage classes, see Storage Classes Supported to Preserve Dimensions.
Generate and review code. The generated code preserves the dimensions of the root-level Inports.
real_T rtPressure; real_T rtTargetVolume; real_T rtTemperature;
You can override the default configurations specified in the Data Defaults tab by configuring individual model data element sources in other tabs such as Inports, Outports, Parameters, Data Stores, and Signals/States. Here is an example workflow that is applicable to the model data element categories.
From the C Code tab, open Code Interface > Individual Element Code Mappings.
In the Code Mappings editor, select the Signals/States tab. The Signals section is currently empty. There can be multiple signals in a given model. Some of these signals might not be important when configuring code generation. You can mark signals as signals of interest that are relevant to your code generation configuration. When you add a signal explicitly, it gets added to the Code Mappings editor.
In the Code Mappings editor, open the Signals/States tab. Select the signal in the Simulink® Editor that you want to add to the Code Mappings editor. Pause on the ellipsis (...) that appears above or below the signal line to open the action bar. Click the Add selected signals to code mappings button. The signal is populated in the Signals table in the Code Mappings editor.
For this example, select the signal going from the subsystem Volume Controller to the outport Actuator Command and click the Add selected signals to code mappings button.
As per the configurations in the Data Defaults tab, the
default storage class for signals is
default configuration for signals also specifies to preserve dimensions of
By default the Storage Class of the individually added
signal is configured as
Auto. You can override the
default configuration for the individual signal by changing the specification of
the added signal under Signals/States tab.
If you want to apply the default settings, set the Storage
Model default: Localizable.
If you want to maintain the same storage class,
Localizable, but not preserve dimensions for the
selected signal, specify Storage Class as
Localizable and clear the
PreserveDimensions property in the Property
If you specify the Storage Class as
Model default, you cannot override the
default configurations specified in Data Defaults tab.
To override the default specifications for the default storage class, select
that storage class and change the configurations for the individual modeling
In the Property Inspector, specify a signal name in the
Identifier property, such as
Generate and review code. The generated code does not preserve dimensions of the individual signal but does for other signals.
/* Definition for custom storage class: Localizable */ static real_T LogSignal; /* '<S2>/Log volume difference' */ real_T VolumeController; /* '<S3>/Gain' */ static real_T rtIterationCount; /* '<S2>/IterationCount' */ static real_T rtIterationCount_g;/* '<S2>/PreviousVolumeErrorAverage' */ static real_T rtVolumedifference;/* '<S1>/Volume difference' */
You can preserve dimensions in the generated code for these storage classes:
To preserve dimensions when you design your own storage class, in the Embedded Coder Dictionary, in the Property Inspector, select the Preserve array dimensions property. Selecting this property preserves dimensions for instances of your storage class. To use the storage class, in the Code Mappings editor, configure the model element categories by specifying Storage Class to the new storage class that you created.
To preserve dimensions when you design your own storage class in the Custom Storage Class Designer, use the Preserve array dimensions property. Preserve array dimensions has these options:
No (default) — Flattens the multidimensional
array to one dimension in the generated code.
Yes — Preserves array dimensions for parameters
of the specified storage class.
Instance Specific — If you want to preserve
array dimensions for each instance of the storage class, enable the
Preserve array dimensions property on the parameter
object. For the Simulink package, this property setting is
Instance Specific by default.
The code generator flattens multidimensional arrays in Simulink buses in the generated code.
The code generator does not preserve dimensions for parameters without data objects.