Class: PetriNet::Net

Inherits:
Base
  • Object
show all
Defined in:
lib/petri_net/net.rb

Instance Attribute Summary collapse

Attributes inherited from Base

#logger

Instance Method Summary collapse

Methods inherited from Base

#next_object_id, #reset

Constructor Details

#initialize(options = {}) {|_self| ... } ⇒ Net

Create new Petri Net definition.

options may be

  • name used as a human usable identifier (defaults to ‘petri_net’)

  • filename (defaults to the name)

  • description (defaults to ‘Petri Net’)

Accepts a block and yields itself

Yields:

  • (_self)

Yield Parameters:

  • _self (PetriNet::Net) —

    the object that the method was called on



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# File 'lib/petri_net/net.rb', line 32

def initialize(options = {}, &block)
    @name = (options[:name] or 'petri_net')
    @filename = (options[:filename] or @name)
    @description = (options[:description] or 'Petri Net')
    @places = Hash.new
    @arcs = Hash.new
    @transitions = Hash.new
    @markings = Hash.new
    @objects = Array.new
    @up_to_date = false
    @w_up_to_date = false

    yield self unless block == nil
end

Instance Attribute Details

#arcs ⇒ Object (readonly)

List of arcs



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# File 'lib/petri_net/net.rb', line 13

def arcs
  @arcs
end

#description ⇒ Object

Description



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# File 'lib/petri_net/net.rb', line 9

def description
  @description
end

#filename ⇒ Object

Storage filename



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# File 'lib/petri_net/net.rb', line 7

def filename
  @filename
end

#markings ⇒ Object (readonly)

List of markings !depricated!



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# File 'lib/petri_net/net.rb', line 18

def markings
  @markings
end

#name ⇒ Object

Human readable name



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# File 'lib/petri_net/net.rb', line 5

def name
  @name
end

#places ⇒ Object (readonly)

List of places



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# File 'lib/petri_net/net.rb', line 11

def places
  @places
end

#transitions ⇒ Object (readonly)

List of transitions



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# File 'lib/petri_net/net.rb', line 15

def transitions
  @transitions
end

Instance Method Details

#<<(object) ⇒ Object Also known as: add_object

Adds an object to the Petri Net. You can add

  • PetriNet::Place

  • PetriNet::Arc

  • PetriNet::Transition

  • Array of these

The Objects are added by PetriNet::Net#add_place, PetriNet::Net#add_arc and PetriNet::Net#add_transition, refer to these to get more information on how they are added raises an RuntimeError if a wring Type is given

returns itself



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# File 'lib/petri_net/net.rb', line 58

def <<(object)
    return if object.nil?  #TODO WORKAROUND There should never be a nil here, even while merging.
    case object.class.to_s
    when "Array"
        object.each {|o| self << o}
    when "PetriNet::Place" 
        add_place(object)
    when "PetriNet::Arc" 
        add_arc(object)
    when "PetriNet::Transition" 
        add_transition(object)
    else 
        raise "(PetriNet) Unknown object #{object.class}."
    end
    self
end

#add_arc(arc) ⇒ Object

Add an arc to the list of arcs.

see PetriNet::Net#add_place



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# File 'lib/petri_net/net.rb', line 94

def add_arc(arc)
    if (arc.validate self) && !@arcs.include?(arc.name)
        if arc.need_update? self
            arc.update self
        end
        @arcs[arc.name] = arc.id
        @objects[arc.id] = arc
        arc.net = self
        return arc.id
    end
    changed_structure
    return false
end

#add_place(place) ⇒ Object

Adds a place to the list of places. Adds the place only if the place is valid and unique in the objects-list of the net

This Method changes the structure of the PetriNet, you will have to recalculate all cached functions



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# File 'lib/petri_net/net.rb', line 80

def add_place(place)
    if place.validate && !@places.include?(place.name) 
        @places[place.name] = place.id
        @objects[place.id] = place
        place.net = self
        return place.id
    end
    changed_structure
    return false
end

#add_transition(transition) ⇒ Object

Add a transition to the list of transitions.

see PetriNet::Net#add_place



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# File 'lib/petri_net/net.rb', line 111

def add_transition(transition)
    if transition.validate && !@transitions.include?(transition.name)
        @transitions[transition.name] = transition.id
        @objects[transition.id] = transition
        transition.net = self
        return transition.id
    end
    changed_structure
    return false
end

#fire(transition) ⇒ Object 



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# File 'lib/petri_net/net.rb', line 297

def fire transition
    get_transition(transition).fire
end

#generate_reachability_graph(unlimited = true) ⇒ Object 



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# File 'lib/petri_net/net.rb', line 215

def generate_reachability_graph(unlimited = true)
    raise "Not implemented yet" unless unlimited
    startmarkings = get_markings
    @graph = PetriNet::ReachabilityGraph.new(self)
    @graph.add_node current_node = PetriNet::ReachabilityGraph::Node.new(markings: get_markings)

    reachability_helper startmarkings, current_node

    set_markings startmarkings
    @graph 
end

#generate_weight_function ⇒ Object 



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# File 'lib/petri_net/net.rb', line 226

def generate_weight_function
    @weight = Hash.new
    @arcs.each_value do |id|
        arc = @objects[id]
        @weight[[arc.source.id,arc.destination.id]] = arc.weight
    end
    @w_up_to_date = true
    @weight
end

#get_arc(name) ⇒ Object

returns the arc refered by the given name or false if there is no arc with this name



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# File 'lib/petri_net/net.rb', line 138

def get_arc(name)
    arc = @objects[@arcs[name]]
    arc.nil? ? false : arc
end

#get_markings ⇒ Object 



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# File 'lib/petri_net/net.rb', line 256

def get_markings
    @places.map{|key,pid| @objects[pid].markings.size}
end

#get_object(id) ⇒ Object 



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# File 'lib/petri_net/net.rb', line 277

def get_object(id)
    @objects[id]
end

#get_objects ⇒ Object 



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# File 'lib/petri_net/net.rb', line 281

def get_objects
    @objects.clone
end

#get_place(name) ⇒ Object

Returns the place refered by the given name or false if there is no place with this name



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# File 'lib/petri_net/net.rb', line 124

def get_place(name)
    place = @objects[@places[name]]
    place.nil? ? false : place
end

#get_transition(name) ⇒ Object

Returns the transition refered by the given name or false if there is no transition with this name



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# File 'lib/petri_net/net.rb', line 131

def get_transition(name)
    trans = @objects[@transitions[name]]
    trans.nil? ? false : trans
end

#load(filename) ⇒ Object 



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# File 'lib/petri_net/net.rb', line 293

def load filename
    @net = YAML.load(File.read(filename))
end

#merge(net) ⇒ Object

Merges two PetriNets Places, transitions and arcs are equal if they have the same name and description, arcs need to have the same source and destination too). With this definition of equality the resultung net will have unique ojects. ATTENTION conflicting capabilities and weights will be lost and the properies of the net you merge to will be used in future #TODO add a parameter to affect this!



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# File 'lib/petri_net/net.rb', line 208

def merge(net)
    return self if self.equal? net
    return false if net.class.to_s != "PetriNet::Net"
    self << net.get_objects
    self
end

#objects_find_index(object) ⇒ Object 



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# File 'lib/petri_net/net.rb', line 285

def objects_find_index(object)
    @objects.find_index object
end

#objects_include?(object) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/petri_net/net.rb', line 273

def objects_include?(object)
    @objects.include?(object)
end

#objects_size ⇒ Object 



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# File 'lib/petri_net/net.rb', line 269

def objects_size
    @objects.count{|o| !o.nil?}
end

#ordinary? ⇒ Boolean

Is this Petri Net ordinary? A Petri Net is said to be ordinary if all of its arc weights are 1’s.

Returns:

  • (Boolean) 


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# File 'lib/petri_net/net.rb', line 151

def ordinary?
    raise "Not implemented yet"
end

#pure? ⇒ Boolean

Is this Petri Net pure? A Petri Net is said to be pure if it has no self-loops.

Returns:

  • (Boolean) 


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# File 'lib/petri_net/net.rb', line 145

def pure?
    raise "Not implemented yet"
end

#save(filename) ⇒ Object 



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# File 'lib/petri_net/net.rb', line 289

def save filename
    File.open(filename, 'w') {|f| @net.to_yaml}
end

#set_markings(markings) ⇒ Object 



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# File 'lib/petri_net/net.rb', line 260

def set_markings(markings)
    i = 0
    @places.each_value do |pid| 
        @objects[pid].set_marking markings[i]
        i = i+1
    end
    changed_state
end

#to_gv ⇒ Object

Generate GraphViz dot string.



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# File 'lib/petri_net/net.rb', line 177

def to_gv
    # General graph options
    str = "digraph #{@name} {\n"
    str += "\t// General graph options\n"
    str += "\trankdir = LR;\n"
    str += "\tsize = \"10.5,7.5\";\n"
    str += "\tnode [ style = filled, fillcolor = white, fontsize = 8.0 ]\n"
    str += "\tedge [ arrowhead = vee, arrowsize = 0.5, fontsize = 8.0 ]\n"
    str += "\n"

    str += "\t// Places\n"
    str += "\tnode [ shape = circle ];\n"
    @places.each_value {|id| str += @objects[id].to_gv }
    str += "\n"

    str += "\t// Transitions\n"
    str += "\tnode [ shape = box, fillcolor = grey90 ];\n"
    @transitions.each_value {|id| str += @objects[id].to_gv }
    str += "\n"

    str += "\t// Arcs\n"
    @arcs.each_value {|id| str += @objects[id].to_gv }
    str += "}\n"    # Graph closure

    return str
end

#to_s ⇒ Object

Stringify this Petri Net.



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# File 'lib/petri_net/net.rb', line 156

def to_s
    str = 
%{Petri Net [#{@name}]
----------------------------
Description: #{@description}
Filename: #{@filename}

Places
----------------------------
#{str = ''; @places.each_value {|p| str += @objects[p].to_s + "\n"}; str }
Transitions
----------------------------
#{str = ''; @transitions.each_value {|t| str += @objects[t].to_s + "\n" }; str }
Arcs
----------------------------
#{str = ''; @arcs.each_value {|a| str += @objects[a].to_s + "\n" }; str}
}
    return str
end

#update ⇒ Object 



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# File 'lib/petri_net/net.rb', line 241

def update
    generate_weight_function
    @up_to_date = true
end

#update? ⇒ Boolean Also known as: up_to_date

is true if, and only if, the cached elements are calculated AND the net hasn’t changed

Returns:

  • (Boolean) 


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# File 'lib/petri_net/net.rb', line 247

def update?
    if @w_up_to_date && true #all up_to_date-caches!!!
        @up_to_date = true
        return @up_to_date
    end
    false
end

#w0(x, y) ⇒ Object 



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# File 'lib/petri_net/net.rb', line 236

def w0(x,y)
    generate_weight_function unless @w_up_to_date
    return @weight[[x,y]].nil? ? 0 : @weight[[x,y]]
end