Inline invariant signals

Transform symbolic names of Invariant signals in generated code

Model Configuration Pane: Code Generation / Optimization

Description

The Inline invariant signals parameter instructs the code generator to transform symbolic names of invariant signals into constant values.

An invariant signal is a block output signal that does not change during Simulink^® simulation. For example, in the following model the signal S3 is an invariant signal. An invariant signal is not the same as an invariant constant. The two constants (1 and 2) and the gain value of 3 are invariant constants. To inline invariant constants, set Default parameter behavior to Inlined.

Model containing two constant blocks that feed into a Sum block. The Sum block output feeds into a gain block, whose output is the signal s3.

Category: Optimization

Dependencies

This parameter is enabled when you set Default parameter behavior to Inlined.

Settings

off (default) | on

On: Simulink Coder™ software uses the numerical values of model parameters, instead of their symbolic names, in generated code. An invariant signal is not inline if it is nonscalar, complex, or the block inport the signal is attached to takes the address of the signal.
Off: Uses symbolic names of model parameters in generated code.

Examples

expand all

Optimize Generated Code Using Inline Invariant Signals

Open Script

This example shows how to use inline invariant signals to optimize the generated code. This optimization transforms symbolic names of invariant signals into constant values.

The InlineInvariantSignals optimization:

Reduces ROM and RAM consumption.
Improves execution speed.

Example Model

Consider the model InvariantSignalsInline.

model = 'InvariantSignalsInline';
open_system(model);

Generate Code

Build the model using Simulink® Coder™.

slbuild(model)

### Searching for referenced models in model 'InvariantSignalsInline'.
### Total of 1 models to build.
### Starting build procedure for: InvariantSignalsInline
### Successful completion of build procedure for: InvariantSignalsInline

Build Summary

Top model targets:

Model                   Build Reason                                         Status                        Build Duration
=========================================================================================================================
InvariantSignalsInline  Information cache folder or artifacts were missing.  Code generated and compiled.  0h 0m 7.5391s

1 of 1 models built (0 models already up to date)
Build duration: 0h 0m 8.2049s

View the generated code without the optimization. These lines of code are in InvariantSignalsInline.c.

cfile = fullfile('InvariantSignalsInline_grt_rtw',...
    'InvariantSignalsInline.c');
coder.example.extractLines(cfile,'/* Output and update for atomic system',...
    '/* Model output', 1, 0);

/* Output and update for atomic system: '<Root>/InlinedConstFcn' */
void InvariantSignal_InlinedConstFcn(int32_T rtu_In1,
  B_InlinedConstFcn_InvariantSi_T *localB, const ConstB_InlinedConstFcn_Invari_T
  *localC)
{
  /* Product: '<S1>/Product' */
  localB->Product = rtu_In1 * localC->Sum_p;
}

Enable Optimization

Open the Configuration Parameters dialog box.
On the Optimization pane, select Inline Invariant Signals.

Alternatively, you can use the command-line API to enable the optimization:

set_param(model, 'InlineInvariantSignals', 'on');

Generate Code with Optimization

The generated code uses the numerical values of the folded constants instead of creating an additional structure.

Build the model using Simulink Coder.

slbuild(model)

### Searching for referenced models in model 'InvariantSignalsInline'.
### Total of 1 models to build.
### Starting build procedure for: InvariantSignalsInline
### Successful completion of build procedure for: InvariantSignalsInline

Build Summary

Top model targets:

Model                   Build Reason                     Status                        Build Duration
=====================================================================================================
InvariantSignalsInline  Generated code was out of date.  Code generated and compiled.  0h 0m 6.4573s

1 of 1 models built (0 models already up to date)
Build duration: 0h 0m 7.3518s

View the generated code with the optimization in InvariantSignalsInline.c.

coder.example.extractLines(cfile,...
    '/* Output and update for atomic system', '/* Model output', 1, 0);

/* Output and update for atomic system: '<Root>/InlinedConstFcn' */
void InvariantSignal_InlinedConstFcn(int32_T rtu_In1,
  B_InlinedConstFcn_InvariantSi_T *localB)
{
  /* Product: '<S1>/Product' */
  localB->Product = rtu_In1 << 5;
}

Close the model and code generation report.

bdclose(model)

Recommended Settings

Application	Setting
Debugging	Off
Traceability	Off
Efficiency	On
Safety precaution	No impact

Programmatic Use

Parameter: InlineInvariantSignals

Type: character vector

Value: 'on' | 'off'

Default: 'off'

Version History

Introduced before R2006a