generate

Class: matlab.DiscreteEventSystem
Namespace: matlab

Event action upon entity creation

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Syntax

[entity,events]=generate(obj,storage,entity,tag)
[entity,events,out1,...]=generate(obj,storage,entity,tag,in1,...)

Description

[entity,events]=generate(obj,storage,entity,tag) specifies event actions of the object when an entity is created inside a storage component.

[entity,events,out1,...]=generate(obj,storage,entity,tag,in1,...) specifies such event actions of the object when the block has one or more input signal ports and/or signal output ports.

Input Arguments

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Discrete-event System object.

Index of the storage element.

Entity to create inside storage element. Entity has these fields:

  • sys (MATLAB structure) — It has these fields:

    • id (double) — Entity ID

    • priority (double) — Entity priority

  • data — Entity data

Tag of the current entity generation event.

Any data inputs of the object. These input arguments exist only when the object has data inputs.

Output Arguments

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Entities created with possibly changed values.

Events to be scheduled for just after entities are created. Use matlab.DiscreteEventSystem class methods to create events. Each event has these fields:

  • type (character vector) — Type of the event

  • delay (double) — Delay before the event

  • priority (double) — Priority of the event

  • Storage (double) — Index of the storage element

  • tag (character vector) — Event tag

  • location (MATLAB structure) — Source or destination location of entity

Data outputs of the object. You must specify these output arguments when the object has data outputs.

Examples

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Initialize attribute values when entity is generated in a storage element.

function [entity,events] = generate(obj,storage,entity,tag)
    % Specify event actions when entity generated in storage.
    % - For entitiy generation event of tag 'Adam', initialize the
    %   entity so that its attribute 'gender' has value '0', and its
    %   priority is '200'.
    % - For entity generation event of tag 'Eve', initialize the
    %   entity so that its attribute 'gender' has value '1', and its
    %   priority is '100'.
    % - An event is returned to forward the entity to storage
    %   element 2 with a time delay of 0.6.
    switch tag
        case 'Adam'
            entity.data.gender = 0;
            entity.sys.priority = 200;
        case 'Eve'
            entity.data.gender = 1;
            entity.sys.priority = 100;
    end
    events = obj.eventForward('storage',2,0.6);
end

This example shows how to create a custom source block that generates entities and to manage discrete states when implementing the discrete-event System object methods.

For more information, see Custom Entity Generator Block with Signal Input and Signal Output.

classdef CustomEntityStorageBlockGeneration < matlab.DiscreteEventSystem...
                                            & matlab.System
    % A custom entity generator block.
    
    % Nontunable properties 
    properties (Nontunable)
        % Generation period
        period = 1;
    end

    properties(DiscreteState)
        % Entity priority
        priority;
        % Entity value
        value;
    end

    % Discrete-event algorithms
    methods
        function [events, out1] = setupEvents(obj)
            % Set up entity generation events at simulation start.
            events = obj.eventGenerate(1,'mygen',obj.period,obj.priority);
            % Set up the initial value of the output signal.
            out1 = 10;
        end

        function [entity,events,out1] = generate(obj,storage,entity,tag,in1)            
            % Specify event actions when entity is generated in storage.            
            entity.data = obj.value;
            % The priority value is assigned from the input signal.
            obj.priority = in1;
            % Output signal is the assigned priority value.
            out1 = obj.priority;
            events = [obj.eventForward('output',1,0) ...
                      obj.eventGenerate(1,'mygen',obj.period,obj.priority)];
        end
    end

    methods(Access = protected)
        
        function entityTypes = getEntityTypesImpl(obj)
            entityTypes = obj.entityType('Material');
        end
        
        function [inputTypes,outputTypes] = getEntityPortsImpl(obj)
            % Specify entity input and output ports. Return entity types at
            % a port as strings in a cell array. Use empty string to
            % indicate a data port.
            inputTypes = {''};
            outputTypes = {'Material',''};
        end

        function resetImpl(obj)
            % Initialize / reset discrete-state properties.
            obj.priority = 10;
            obj.value = 1:12;            
        end
        
        function [storageSpecs, I, O] = getEntityStorageImpl(obj)
            storageSpecs = obj.queueFIFO('Material', 1);
            I = 0;
            O = [1 0];
        end   

        function num = getNumInputsImpl(obj)
            % Define total number of inputs for system with optional
            % inputs.
            num = 1;
        end
        
        function num = getNumOutputsImpl(~)
            % Define total number of outputs.
            num = 2;
        end  
        function [out1 out2] = getOutputSizeImpl(obj)
            % Return size for each output port.
            out1 = [1 12];
            out2 = 1;
        end

        function [out1 out2] = getOutputDataTypeImpl(obj)
            % Return data type for each output port.
            out1 = "double";
            out2 = "double";
        end

        function [out1 out2] = isOutputComplexImpl(obj)
            % Return true for each output port with complex data.
            out1 = false;
            out2 = false;
        end

        function [sz,dt,cp] = getDiscreteStateSpecificationImpl(obj,name)
            % Return size, data type, and complexity of discrete-state
            % specified in name.
            switch name
                case 'priority'
                    sz = [1 1];
                case 'value'
                    sz = [1 12];
            end
            dt = "double";
            cp = false;           
        end
    end
end

Version History

Introduced in R2016a

See Also

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