find_system

Find models, blocks, lines, ports, and annotations

Syntax

Objects = find_system

Objects = find_system(Model)

Objects = find_system(Name,Value)

Objects = find_system(Model,Name,Value)

Description

Objects = find_system returns loaded models and their blocks, including subsystems.

Objects = find_system(Model) returns the specified model and its blocks.

Objects = find_system(Name,Value) returns loaded models and the objects in those models that meet the criteria specified by one or more Name,Value pair arguments. You can use this syntax to specify search constraints and to search for specific parameter values. Specify the search constraints before the parameter and value pairs.

Objects = find_system(Model,Name,Value) returns the objects in the specified model that meet the specified criteria.

Examples

Find Loaded Models and Libraries and Their Blocks

Open the example. Then, load the vdp model.

load_system('vdp')

Find all loaded models and libraries and their blocks.

find_system

ans = 13×1 cell
    {'vdp'                }
    {'vdp/Callback Button'}
    {'vdp/Constant'       }
    {'vdp/Mu'             }
    {'vdp/Product'        }
    {'vdp/Scope'          }
    {'vdp/Square'         }
    {'vdp/Sum'            }
    {'vdp/Sum1'           }
    {'vdp/x1'             }
    {'vdp/x2'             }
    {'vdp/Out1'           }
    {'vdp/Out2'           }

Find Specific Model and Its Blocks

Open the example. Then, load the vdp and ex_sldemo_clutch models.

load_system({'vdp','ex_sldemo_clutch'})

Find the vdp model and its blocks.

find_system('vdp')

ans = 13×1 cell
    {'vdp'                }
    {'vdp/Callback Button'}
    {'vdp/Constant'       }
    {'vdp/Mu'             }
    {'vdp/Product'        }
    {'vdp/Scope'          }
    {'vdp/Square'         }
    {'vdp/Sum'            }
    {'vdp/Sum1'           }
    {'vdp/x1'             }
    {'vdp/x2'             }
    {'vdp/Out1'           }
    {'vdp/Out2'           }

Find Loaded Models, Subsystems, and Libraries

Open the example. Then, load the vdp model.

load_system('vdp')

Find all loaded models, subsystems, and libraries. A subsystem name is returned only if the subsystem can be loaded independently.

find_system('type','block_diagram')

ans = 1×1 cell array
    {'vdp'}

Search Children of Subsystem

Open the example. Then, load the ex_sldemo_clutch model.

load_system('ex_sldemo_clutch')

Return the names of all Goto blocks that are children of the Unlocked subsystem in the ex_sldemo_clutch model.

find_system('ex_sldemo_clutch/Unlocked','SearchDepth',1,'BlockType','Goto')

ans = 2×1 cell
    {'ex_sldemo_clutch/Unlocked/Goto' }
    {'ex_sldemo_clutch/Unlocked/Goto1'}

Search Using Multiple Criteria

Open the example. Then, load the vdp model.

load_system('vdp')

Find blocks in the vdp model that meet these two criteria.

• The block is an Integrator block.

• The value of Initial condition is 0.

find_system('vdp','BlockType','Integrator','InitialCondition','0')

ans = 1×1 cell array
    {'vdp/x2'}

Find Lines and Annotations

Open the example. Then, load the vdp model.

load_system('vdp')

Find the lines in the vdp model using the find_system function. To include lines in the search, specify 'FindAll' as 'on'.

l = find_system('vdp','FindAll','on','type','line')

l = 20×1

  363.0094
  362.0090
  361.0088
  360.0087
  359.0073
  358.0084
  357.0110
  356.0096
  355.0095
  354.0084
  353.0089
  352.0072
  351.0084
  350.0099
  349.0087
      ⋮

Find the annotations in the vdp model using the find_system function. To include annotations in the search, specify 'FindAll' as 'on'.

an = find_system('vdp','FindAll','on','type','annotation')

an = 3×1

  366.0088
  365.0090
  364.0096

Search for Specific Block Parameter Value

Open the example. Then, load the vdp and f14 models.

models={'vdp','f14'};
load_system(models)

Find any blocks with Block Dialog box parameters whose value is 3 in the vdp and f14 models.

find_system(models,'BlockDialogParams','3')

ans = 3×1 cell
    {'vdp/Square'                                              }
    {'f14/Aircraft↵Dynamics↵Model/Rotary Gust↵qGust (rad//sec)'}
    {'f14/Controller/q (rad//sec)'                             }

Search Using Regular Expressions

Open the example. Then, load the ex_sldemo_clutch and vdp models.

load_system({'ex_sldemo_clutch','vdp'})

Find all blocks in the top level of the currently loaded models with a Block Parameters dialog box parameter value that starts with 3.

find_system('SearchDepth','1','regexp','on','BlockDialogParams','^3')

ans = 4×1 cell
    {'vdp/Scope'         }
    {'vdp/Scope'         }
    {'vdp/Square'        }
    {'ex_sldemo_clutch/w'}

Regular Expression Search for Partial Match

When you search using regular expressions, you can specify a part of the character vector you want to match to return all objects that contain that character vector.

Find all the Integrator blocks in the ex_sldemo_clutch model.

load_system('ex_sldemo_clutch');
ports=find_system('ex_sldemo_clutch','regexp','on','blocktype','Integrator')

ports = 3×1 cell
    {'ex_sldemo_clutch/Locked/Engine//Vehicle↵Integrator'}
    {'ex_sldemo_clutch/Unlocked/Engine↵Integrator'       }
    {'ex_sldemo_clutch/Unlocked/Vehicle↵Integrator'      }

Update Library Links in a Subsystem

Suppose you have a model named myModel that contains a single subsystem, which is a library link. After the model was last opened, a Gain block was added to the corresponding subsystem in the library.

Open the model. Use find_system with 'FollowLinks' set to 'off'. The command does not follow the library links into the subsystem and returns only the subsystem at the top level.

open_system('myModel')
find_system(bdroot,'LookUnderMasks','all','FollowLinks', 'off')

ans = 

    'myModel'
    'myModel/Subsystem'

Use find_system with 'FollowLinks' set to 'on'. find_system updates the library links and returns the block in the subsystem.

find_system(bdroot,'LookUnderMasks','all','FollowLinks','on')

Updating Link: myModel/Subsystem/Gain
Updating Link: myModel/Subsystem/Gain

ans = 

    'myModel'
    'myModel/Subsystem'
    'myModel/Subsystem/Gain'

Return Values as Handles

When you make multiple function calls that require you to specify the model or block the function acts on, use handles instead of file paths to specify the model or block.

Specify the vdp model as a handle in multiple calls to the find_system function.

Open the example. Then, load the vdp model.

load_system('vdp')

Get the handle of the vdp model.

h = get_param('vdp','Handle')

h = 
153.0038

Find Block Parameters dialog box parameters in the vdp model with a value of 0. Specify the model to search as the handle of the vdp model.

find_system(h,'BlockDialogParams','0')

ans = 8×1

  288.0096
  288.0096
  295.0095
  337.0095
  340.0074
  340.0074
  342.0079
  342.0079

Find block parameters in the vdp model with a Block Parameters dialog box parameter value that starts with 3. Specify the model to search as the handle of the vdp model.

find_system(h,'regexp','on','BlockDialogParams','^3')

ans = 3×1

  295.0095
  295.0095
  298.0115

Find blocks in the vdp model whose block name contains the character vector 'port'. Specify the model to search as the handle of the vdp model.

find_system(h,'regexp','on','blocktype','port')

ans = 2×1

  340.0074
  342.0079

Filter find_system Search Using Custom MatchFilter Functions

Use the MatchFilter argument with a custom filter function to find blocks other than Inport and Outport blocks in the vdp model.

The custom function for this example is defined in the file nonInOutBlocks.m.

function match = nonInOutBlocks(handle)
    match = true;
    if strcmp(get_param(handle,'Type'),'block')
        blockType = get_param(handle,'BlockType');
        if strcmp(blockType,'Inport') || strcmp(blockType,'Outport')
            match = false;
        end
    end
end

Provide the function handle as the value of the MatchFilter argument.

load_system('vdp');
blks = find_system('vdp','MatchFilter',@nonInOutBlocks);

Find Variant Blocks Using find_system with Built-In MatchFilter Functions

Simulink® provides built-in functions that you can use to find variant blocks in a model. For more information, see MatchFilter.

Load the slexVariantSubsystems model.

model = 'slexVariantSubsystems';
load_system(model);
assignin('base','VSS_MODE',2);

Use the Simulink.match.activeVariants function to find variant blocks that are active in simulation after model compilation.

set_param(model,'SimulationCommand','update');
find_system(model,'MatchFilter',@Simulink.match.activeVariants);

Use the Simulink.match.codeCompileVariants function to find variant choices that are part of the generated C code after model compilation.

slexVariantSubsystems([],[],[],'compileForCodegen');
find_system(model,'MatchFilter',@Simulink.match.codeCompileVariants);
slexVariantSubsystems([],[],[],'term');

Note: To get correct results, you must compile the model before using Simulink.match.activeVariants and Simulink.match.codeCompileVariants filters. If the model is not compiled, these filters return all blocks in the model.

Use the Simulink.match.allVariants function to find all blocks irrespective of whether the block is active or inactive due to variants.

find_system(model,'MatchFilter',@Simulink.match.allVariants);

Use the Simulink.match.legacy.filterOutCodeInactiveVariantSubsystemChoices function to find Variant Subsystem choice blocks that are active in simulation or part of generated code at edit-time. For information on the limitations of edit-time filters, see MatchFilter.

find_system(model, ...
 'MatchFilter',@Simulink.match.legacy.filterOutCodeInactiveVariantSubsystemChoices);

Use the Simulink.match.legacy.filterOutInactiveVariantSubsystemChoices function to find active Variant Subsystem choice blocks at edit-time. For information on the limitations of edit-time filters, see MatchFilter.

find_system(model, ...
 'MatchFilter', @Simulink.match.legacy.filterOutInactiveVariantSubsystemChoices);

Use the Simulink.match.variantAssemblySubsystems function to find all Variant Assembly Subsystem blocks in the slexVariantAssemblySubsystemWithMaskInLabel model.

load_system('slexVariantAssemblySubsystemWithMaskInLabel');
find_system('slexVariantAssemblySubsystemWithMaskInLabel','MatchFilter',@Simulink.match.variantAssemblySubsystems);

Compare Pre-Compile and Post-Compile Behavior of Match Filters for Variant Blocks

This example compares the pre-compile and post-compile results for the built-in find_system MatchFilter functions to find variant blocks. These filters help to find variant blocks that are active in simulation or part of the generated code:

• Simulink.match.activeVariants

• Simulink.match.codeCompileVariants

1. Open the model slexVariantSubsystems. The model is configured to generate code using Embedded Coder® and uses an ERT-based system target file, ert.tlc.

model="slexVariantSubsystems";
open_system(model);

2. Set the VariantActivationTime parameter of the Controller block to code compile. For this activation time, the code generated using Embedded Coder includes both the active and inactive variant choices.

set_param('slexVariantSubsystems/Controller','VariantActivationTime','code compile');

3. Set the TreatAsAtomicUnit parameter to on for the choices of the Controller block. This step is needed to use code compile activation time for the Controller block.

set_param('slexVariantSubsystems/Controller/Linear Controller', 'TreatAsAtomicUnit', 'on');
set_param('slexVariantSubsystems/Controller/Nonlinear Controller', 'TreatAsAtomicUnit', 'on');

find_system Results Before Model Compilation

Using the built-in match filters before compiling the model returns all blocks in the model, irrespective of their variant activeness.

find_system(model,MatchFilter=@Simulink.match.activeVariants)

ans = 25×1 cell
    {'slexVariantSubsystems'                                                   }
    {'slexVariantSubsystems/Controller'                                        }
    {'slexVariantSubsystems/Controller/sensor1'                                }
    {'slexVariantSubsystems/Controller/sensor2'                                }
    {'slexVariantSubsystems/Controller/sensor3'                                }
    {'slexVariantSubsystems/Controller/Linear Controller'                      }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor1'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor2'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor3'              }
    {'slexVariantSubsystems/Controller/Linear Controller/Add'                  }
    {'slexVariantSubsystems/Controller/Linear Controller/Discrete↵Transfer Fcn'}
    {'slexVariantSubsystems/Controller/Linear Controller/Out1'                 }
    {'slexVariantSubsystems/Controller/Nonlinear Controller'                   }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor1'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor2'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor3'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/1-D Lookup Table'  }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/Add'               }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/Out1'              }
    {'slexVariantSubsystems/Controller/Out1'                                   }
    {'slexVariantSubsystems/Scope'                                             }
    {'slexVariantSubsystems/sine1'                                             }
    {'slexVariantSubsystems/sine2'                                             }
    {'slexVariantSubsystems/sine3'                                             }
    {'slexVariantSubsystems/Out1'                                              }

find_system(model,MatchFilter=@Simulink.match.codeCompileVariants)

ans = 25×1 cell
    {'slexVariantSubsystems'                                                   }
    {'slexVariantSubsystems/Controller'                                        }
    {'slexVariantSubsystems/Controller/sensor1'                                }
    {'slexVariantSubsystems/Controller/sensor2'                                }
    {'slexVariantSubsystems/Controller/sensor3'                                }
    {'slexVariantSubsystems/Controller/Linear Controller'                      }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor1'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor2'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor3'              }
    {'slexVariantSubsystems/Controller/Linear Controller/Add'                  }
    {'slexVariantSubsystems/Controller/Linear Controller/Discrete↵Transfer Fcn'}
    {'slexVariantSubsystems/Controller/Linear Controller/Out1'                 }
    {'slexVariantSubsystems/Controller/Nonlinear Controller'                   }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor1'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor2'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor3'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/1-D Lookup Table'  }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/Add'               }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/Out1'              }
    {'slexVariantSubsystems/Controller/Out1'                                   }
    {'slexVariantSubsystems/Scope'                                             }
    {'slexVariantSubsystems/sine1'                                             }
    {'slexVariantSubsystems/sine2'                                             }
    {'slexVariantSubsystems/sine3'                                             }
    {'slexVariantSubsystems/Out1'                                              }

find_system Results After Model Compilation

Compile the model.

set_param(model,"SimulationCommand","update");

Using the Simulink.match.activeVariants filter returns the blocks that are active in simulation.

find_system(model,MatchFilter=@Simulink.match.activeVariants)

ans = 18×1 cell
    {'slexVariantSubsystems'                                                   }
    {'slexVariantSubsystems/Controller'                                        }
    {'slexVariantSubsystems/Controller/sensor1'                                }
    {'slexVariantSubsystems/Controller/sensor2'                                }
    {'slexVariantSubsystems/Controller/sensor3'                                }
    {'slexVariantSubsystems/Controller/Linear Controller'                      }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor1'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor2'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor3'              }
    {'slexVariantSubsystems/Controller/Linear Controller/Add'                  }
    {'slexVariantSubsystems/Controller/Linear Controller/Discrete↵Transfer Fcn'}
    {'slexVariantSubsystems/Controller/Linear Controller/Out1'                 }
    {'slexVariantSubsystems/Controller/Out1'                                   }
    {'slexVariantSubsystems/Scope'                                             }
    {'slexVariantSubsystems/sine1'                                             }
    {'slexVariantSubsystems/sine2'                                             }
    {'slexVariantSubsystems/sine3'                                             }
    {'slexVariantSubsystems/Out1'                                              }

Using the Simulink.match.codeCompileVariants filter returns the blocks that are part of the generated C code.

slexVariantSubsystems([],[],[],"compileForCodegen");
slexVariantSubsystems([],[],[],"term");
find_system("slexVariantSubsystems",MatchFilter=@Simulink.match.codeCompileVariants)

ans = 25×1 cell
    {'slexVariantSubsystems'                                                   }
    {'slexVariantSubsystems/Controller'                                        }
    {'slexVariantSubsystems/Controller/sensor1'                                }
    {'slexVariantSubsystems/Controller/sensor2'                                }
    {'slexVariantSubsystems/Controller/sensor3'                                }
    {'slexVariantSubsystems/Controller/Linear Controller'                      }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor1'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor2'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor3'              }
    {'slexVariantSubsystems/Controller/Linear Controller/Add'                  }
    {'slexVariantSubsystems/Controller/Linear Controller/Discrete↵Transfer Fcn'}
    {'slexVariantSubsystems/Controller/Linear Controller/Out1'                 }
    {'slexVariantSubsystems/Controller/Nonlinear Controller'                   }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor1'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor2'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor3'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/1-D Lookup Table'  }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/Add'               }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/Out1'              }
    {'slexVariantSubsystems/Controller/Out1'                                   }
    {'slexVariantSubsystems/Scope'                                             }
    {'slexVariantSubsystems/sine1'                                             }
    {'slexVariantSubsystems/sine2'                                             }
    {'slexVariantSubsystems/sine3'                                             }
    {'slexVariantSubsystems/Out1'                                              }

Find All Blocks Irrespective of Block Activeness

Use the Simulink.match.allVariants() filter to find all blocks irrespective of whether the block is active or inactive due to variants.

find_system(model,MatchFilter=@Simulink.match.allVariants)

ans = 25×1 cell
    {'slexVariantSubsystems'                                                   }
    {'slexVariantSubsystems/Controller'                                        }
    {'slexVariantSubsystems/Controller/sensor1'                                }
    {'slexVariantSubsystems/Controller/sensor2'                                }
    {'slexVariantSubsystems/Controller/sensor3'                                }
    {'slexVariantSubsystems/Controller/Linear Controller'                      }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor1'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor2'              }
    {'slexVariantSubsystems/Controller/Linear Controller/sensor3'              }
    {'slexVariantSubsystems/Controller/Linear Controller/Add'                  }
    {'slexVariantSubsystems/Controller/Linear Controller/Discrete↵Transfer Fcn'}
    {'slexVariantSubsystems/Controller/Linear Controller/Out1'                 }
    {'slexVariantSubsystems/Controller/Nonlinear Controller'                   }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor1'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor2'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/sensor3'           }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/1-D Lookup Table'  }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/Add'               }
    {'slexVariantSubsystems/Controller/Nonlinear Controller/Out1'              }
    {'slexVariantSubsystems/Controller/Out1'                                   }
    {'slexVariantSubsystems/Scope'                                             }
    {'slexVariantSubsystems/sine1'                                             }
    {'slexVariantSubsystems/sine2'                                             }
    {'slexVariantSubsystems/sine3'                                             }
    {'slexVariantSubsystems/Out1'                                              }

Input Arguments

Model — Model to search

path name | cell array of path names | handle | vector of handles

Model to search, specified as the full model path name, a cell array of model path names, a handle, or a vector of handles.

Example: 'MyModel/Subsystem1'

Example: {'vdp','ex_sldemo_clutch'}

Name-Value Arguments

Specify optional arguments as Name1 = Value1,...,NameN = ValueN, where Name is the argument name and Value is the value you want to assign to the argument. Name-value arguments must appear after other arguments.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: SearchDepth = '0',LookUnderMasks = 'none',BlockType = 'Goto' searches in loaded models, excluding masked subsystems, for Goto blocks.

When you use the find_system function, Name = Value arguments can include:

• Search criteria, for example CaseSensitive = 'on'

• Parameter values, for example BlockType = 'Gain'

You can specify the search criteria in any order and the parameter values in any order, but the search criteria must precede the parameter values.

For information about block parameters, see Programmatically Specify Block Parameters and Properties.

BlockDialogParams — Option to search block parameters for specified value

character vector | string scalar

Option to search block dialog box parameters for a value, specified as a character vector or string scalar. This argument must follow the other search criteria arguments.

CaseSensitive — Option to consider case when matching search results

'on' (default) | 'off'

Option to consider text case when matching, specified as 'on' or 'off'.

FindAll — Option to include lines, ports, and annotations within models in search

'off' (default) | 'on'

Option to include lines, ports, and annotations within models in the search, specified as 'on' or 'off'. When this option is set to 'on', find_system returns a vector of handles regardless of whether you specify the Model argument as the full model path name, a cell array of model path names, a handle, or a vector of handles.

Type — Option to search for specific type of model element

'block' (default) | 'line' | 'port' | 'annotation'

Option to search for a specific type of model element, specified as one of these:

• 'block'

• 'line'

• 'port'

• 'annotation'

To find lines, ports, or annotations in the model, you must first specify the value of FindAll as 'on', and then the value of Type. You can specify other search criteria options before, after, and between FindAll and Type. For example, to find an annotation in a model named myModel and look under masks, enter this command in the MATLAB^® Command Window.

find_system('myModel', FindAll =  'on',...
LookUnderMasks = 'all',Type = 'annotation')

FirstResultOnly — Option to return only first result and then stop search

'off' (default) | 'on'

Option to return only the first result and then stop the search, specified as 'on' or 'off'.

LookInsideSubsystemReference — Option to search inside referenced subsystem

'on' (default) | 'off'

Option to look inside a referenced subsystem in a model and list child blocks, specified as 'on' or 'off'.

LookUnderModelBlocks — Option to search under model blocks

'off' (default) | 'on'

Option to search under blocks in a model and list child blocks, specified as 'on' or 'off'. When you enable LookUnderModelBlocks, find_system loads the top-level and all the referenced models, and searches recursively in all models in the hierarchy.

FollowLinks — Option to follow links into library blocks in search

'off' (default) | 'on'

Option to follow links into library blocks, specified as 'on' or 'off'. If you do not specify a model to search, find_system includes loaded libraries in the results, whether you set 'FollowLinks' to 'on' or 'off'. You can use 'FollowLinks' with 'LookUnderMasks' to update library links in subsystems. See Update Library Links in a Subsystem.

IncludeCommented — Option to include commented blocks in search

'off' (default) | 'on'

Option to include commented blocks in the search, specified as 'on' or 'off'.

LoadFullyIfNeeded — Option to load any partially loaded models in search

'on' (default) | 'off'

Option to load any partially loaded models, specified as 'on' to load models or 'off' to disable loading. Use this option, for example, to prevent load warnings.

LookUnderMasks — Options for searching under masks

'graphical' (default) | 'none' | 'functional' | 'all'

Option for searching under masks, specified as one of these:

• 'none' — Search skips masked subsystems.

• 'all' — Search includes all masked subsystems.

• 'functional' — Search includes masked subsystems that have icon drawing commands or mask initialization commands without having parameters, description, help strings, and UI elements.

• 'graphical' — Search includes masked subsystems that have only icon drawing commands without having workspaces, dialogs, help strings, and UI elements.

Note

The option 'none' replaces the former option 'off'. The option 'all' replaces the former option 'on'.

RegExp — Option to treat search expressions as regular expressions

'off' (default) | 'on'

Option to treat search expressions as regular expressions, specified as 'on' or 'off'. When 'RegExp' is set to 'on', the search treats search expressions as regular expressions. To learn more about MATLAB regular expressions, see Regular Expressions.

SearchDepth — Option to restrict search path

positive integer, character vector, or string scalar

Option to restrict the search depth to the specified level, specified as a positive integer, character vector, or string scalar. For example, specify '0' to search loaded models only, '1' for blocks and subsystems of the top level of the model hierarchy,'2' for the top level of the model hierarchy and its children, and so forth. The default is to search all levels.

Variants — Options for searching variants

'ActiveVariants' (default) | 'AllVariants' | 'ActivePlusCodeVariants'

Note

The Variants argument will be removed. Use MatchFilter instead. For more information, see Version History.

Option for searching variants, specified as one of these:

• 'ActiveVariants' — Search only the active variant choice in the Variant Subsystem.

• 'AllVariants' — Search all variant choices in the Variant Subsystem.

• 'ActivePlusCodeVariants' — Search all variant choices in the Variant Subsystem that are active in simulation and is part of the generated code.

This search constraint applies only to Variant Subsystem blocks that have the Variant control mode set to expression or label. Use the find_system function with the MatchFilter option to operate on all types of variant blocks.

MatchFilter — Option to match and filter elements in search

function handle

Option to match and filter elements such as blocks, model, lines, ports, and annotations in a search, specified as a function handle. Use MatchFilter to determine whether elements should be included or skipped in a search.

The argument:

• Allows you to filter elements with custom filter functions

• Avoids processing elements when filters do not match

• Applies complex filters on blocks, lines, or annotations, to filter the results internally

The named function must be defined within a MATLAB program file. The function takes the handle of the element as input and returns two outputs.

 function [match, prune] = func(element)
 

• The input element is the handle of the component being processed, for example the block handle.

• The first output, match, is a logical value. If false, search skips the element.

• The second output, prune, is an optional logical value that only applies when element is a subsystem. The default value is false. If this value is set to true, the entire subsystem is omitted from the search.

For an example that shows how to create a custom match filter function, see Filter find_system Search Using Custom MatchFilter Functions.

Variants: Simulink^® provides these built-in match filter functions to find variant blocks.

Post-compile time filter functions:

• Simulink.match.activeVariants — Filter function to find blocks that are active in simulation after model compilation.

• Simulink.match.codeCompileVariants — Filter function to find blocks that are part of generated code after model compilation.

• Simulink.match.allVariants — Filter function to find all blocks irrespective of whether the block is active or inactive due to variants.

• Simulink.match.variantAssemblySubsystems — Filter function to find all the Variant Assembly Subsystem blocks.

For an example that shows the use of these filters, see Find Variant Blocks Using find_system with Built-In MatchFilter Functions.

Note

When using the @Simulink.match.allVariants match filter to identify active and inactive variant choices of a Variant Subsystem block with the update diagram activation time, the function lists the inactive variant choices but executes the LoadFcn callback only for the active variant choice. It does not execute the LoadFcn callbacks for inactive variant choices, as they do not impact the model execution.

To get correct results, you must compile the model before using Simulink.match.activeVariants and Simulink.match.codeCompileVariants filters. If the model is not compiled, these filters return all blocks in the model. For an example that compares the pre-compile and post-compile time results for these filters, see Compare Pre-Compile and Post-Compile Behavior of Match Filters for Variant Blocks.

Edit-time filter functions for Variant Subsystem blocks:

• Simulink.match.legacy.filterOutCodeInactiveVariantSubsystemChoices — Filter function to find Variant Subsystem choice blocks that are active in simulation or part of generated code. This function produces similar results as the 'ActivePlusCodeVariants' option of the Variants argument.

• Simulink.match.legacy.filterOutInactiveVariantSubsystemChoices — Filter function to find active Variant Subsystem choice blocks. This function produces similar results as the 'ActiveVariants' option of the Variants argument.

Limitations of edit-time filters:

• The filters do not use the post-compile block activeness information in the CompiledVariantInfo block parameter.

• The filters apply only to Variant Subsystem blocks that have these block parameter settings:

  • Variant control mode set to expression or label

  • Propagate conditions outside of variant subsystem set to off

• The filters can identify if a block handle is inside the active choice of a Variant Subsystem only when used within the context of find_system, find_mdlrefs, and Simulink.FindOptions.

To operate on all types of variant blocks, use the Simulink.match.codeCompileVariants or Simulink.match.activeVariants filters after model compilation.

SegmentType — Option to search for specific type of signal line segment

'trunk' | 'branch'

Option to search for a specific type of signal line segment, specified as one of these:

• 'trunk'– Line segment connected to an output port or not connected to a source

• 'branch'– Line segment connected to the trunk

To find signal line segments of a specific type, you must first specify the value of FindAll as 'on', then specify the value of Type as 'line', and then specify the value of SegmentType. You can specify other search criteria options before, after, and between the FindAll, Type, and SegmentType options. For example, to find signal line segments in a model named myModel that are trunks and look under masks, enter this command in the MATLAB Command Window.

trunkSegments = find_system('myModel',FindAll = 'on',..
LookUnderMasks = 'all',type='line',SegmentType = 'trunk');

Output Arguments

Objects — Matching objects

cell array of path names | vector of handles

Matching objects found, returned as a cell array of path names or a vector of handles.

The objects found are returned as a cell array of path names when both of these conditions are met.

• The search criteria option FindAll is set to its default value, 'off'.

• You specified Model as a path name or cell array of path names, or you did not specify a model.

The objects found are returned as a vector of handles when at least one of these conditions is met.

• You set the value of FindAll to 'on'.

• You specified Model as a handle or vector of handles.

Version History

Introduced before R2006a

R2025a: New option to look under blocks in model and references

You can use the LookUnderModelBlocks option to enable search under blocks in a model. For example, find_system("mymodel",LookUnderModelBlocks=on,BlockType="Constant") searches for Constant blocks under all blocks in the model mymodel and all of the referenced models.

R2022b: Warnings for removal of Variants argument

As part of the removal of the Variants argument in a future release, these warnings have been introduced:

• When you use the find_system function without the Variants argument, the function generates a warning if it skips the inactive choice of a Variant Subsystem block during the search.

  Consider a model with a Variant Subsystem block that has two variant choices, Linear Controller and Nonlinear Controller. The Nonlinear Controller block is the active choice.

  This command skips the inactive Linear Controller block and generates a warning.

  blocks = find_system('sldemo_variant_subsystems/Controller')

  Warning: Using find_system without the 'Variants' argument skips inactive Variant 
  Subsystem blocks in the search. This behavior will change in a future release to 
  look at all choices of the Variant Subsystem. To find blocks thatare active in 
  simulation or code generation, compile the model and use the built-in variant 
  filters with the 'MatchFilter' option.
  
  blocks =
  
    12×1 cell array
  
      {'sldemo_variant_subsystems/Controller'                                      }
      {'sldemo_variant_subsystems/Controller/sensor1'                              }
      {'sldemo_variant_subsystems/Controller/sensor2'                              }
      {'sldemo_variant_subsystems/Controller/sensor3'                              }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller'                 }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/sensor1'         }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/sensor2'         }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/sensor3'         }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/1-D Lookup Table'}
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/Add'             }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/Out1'            }
      {'sldemo_variant_subsystems/Controller/Out1'                                 }

• When you use the Variants argument with its value set to 'AllVariants', the function generates a warning.

  blocks = find_system('sldemo_variant_subsystems/Controller',...
                       'Variants','AllVariants')

  Warning: 'Variants' will be removed. Instead of using 'Variants' with value set to
  'AllVariants', use 'MatchFilter' with value set to @Simulink.match.allVariants.
  
  blocks =
  
    19×1 cell array
  
      {'sldemo_variant_subsystems/Controller'                                        }
      {'sldemo_variant_subsystems/Controller/sensor1'                                }
      {'sldemo_variant_subsystems/Controller/sensor2'                                }
      {'sldemo_variant_subsystems/Controller/sensor3'                                }
      {'sldemo_variant_subsystems/Controller/Linear Controller'                      }
      {'sldemo_variant_subsystems/Controller/Linear Controller/sensor1'              }
      {'sldemo_variant_subsystems/Controller/Linear Controller/sensor2'              }
      {'sldemo_variant_subsystems/Controller/Linear Controller/sensor3'              }
      {'sldemo_variant_subsystems/Controller/Linear Controller/Add'                  }
      {'sldemo_variant_subsystems/Controller/Linear Controller/Discrete↵Transfer Fcn'}
      {'sldemo_variant_subsystems/Controller/Linear Controller/Out1'                 }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller'                   }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/sensor1'           }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/sensor2'           }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/sensor3'           }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/1-D Lookup Table'  }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/Add'               }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/Out1'              }
      {'sldemo_variant_subsystems/Controller/Out1'                                   }

R2022a: New built-in match filter to find all variant blocks

You can use the built-in match filter, Simulink.match.allVariants, to find all the blocks in a variant model regardless of whether the block is active or inactive due to variants. This filter is the recommended replacement for the AllVariants option.

To be removed	Recommended Replacement
find_system(model,'Variants', ... 'AllVariants');	find_system(model,'MatchFilter', ... @Simulink.match.allVariants);

R2021a: Default behavior has changed for Variants and MatchFilter arguments in model with variant blocks

• Variants: When you use the find_system function without specifying the Variants argument, the function currently includes only the active variant choice for Variant Subsystem blocks in the search by default.

  For other variant blocks such as Variant Source, Variant Sink, or Variant Subsystem blocks with the Propagate conditions outside of variant subsystem parameter set to on, the function includes all choices in the search.

  Consider a model with a Variant Subsystem that has two variant choices, Linear Controller and Nonlinear Controller.

  This command returns only the active Add blocks in the model.

  add_blocks = find_system('sldemo_variant_subsystems/Controller',...
  'BlockType','Sum')

  add_blocks =
  
    1×1 cell array
  
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/Add'}

• MatchFilter: When you use the find_system function with the MatchFilter argument, the function applies the filters on the active and inactive variant choices by default.

  Consider a model with a Variant Subsystem that has two variant choices, Linear Controller and Nonlinear Controller. The filter function findAddBlocks finds all the Add blocks in the model.

   function match = findAddBlocks(handle)
   match = strcmp(get_param(handle, 'Type'), 'block') &&...
   strcmp(get_param(handle, 'BlockType'), 'Sum');
   end

  This command returns the active and inactive Add blocks in the model.

  add_blocks = find_system('sldemo_variant_subsystems','MatchFilter',...
  @findAddBlocks)

  add_blocks =
  
    2×1 cell array
  
      {'sldemo_variant_subsystems/Controller/Linear Controller/Add'   }
      {'sldemo_variant_subsystems/Controller/Nonlinear Controller/Add'}
  

R2021a: Variants argument will be removed

The Variants argument will be removed from find_system in a future release. Function calls that use the Variants argument continue to work with a warning.

Using the find_system function with the Variants argument produces inconsistent search results. The find_system function is an edit-time operation, but to determine whether a block is active in a model with all types of variant blocks, you need to compile the model.

To find variant blocks that are active during simulation or code generation, compile the model and use the find_system function with the MatchFilter argument.

This table lists the recommended replacement for different values of the Variants argument.

To Be Removed	Recommended Replacement
find_system(model,'Variants', ... 'ActiveVariants');	set_param(model,'SimulationCommand','update'); find_system(model,'MatchFilter', ... @Simulink.match.activeVariants);
find_system(model,'Variants', ... 'ActivePlusCodeVariants');	model([], [], [], 'compileForCodegen'); activeBlks= find_system(model,'MatchFilter', ... @Simulink.match.codeCompileVariants); model([], [], [], 'term');

When you use the find_system function, you cannot specify both of the MatchFilter and Variants arguments.

This command produces an error.

find_system(bdroot,'MatchFilter',@Simulink.match.activeVariants,...
    'Variants','ActiveVariants');

R2020b: Filter elements during search with MatchFilter

To match and filter model elements during a search, you can define a custom filter function and pass the function handle as value to the MatchFilter name-value argument.

To find variant blocks that are active in a simulation or part of the generated code, you can use the built-in match filter functions, Simulink.match.activeVariants, Simulink.match.codeCompileVariants, and Simulink.match.allVariants, after compiling the model.