Class: Solve::Solver
- Inherits:
-
Object
- Object
- Solve::Solver
- Defined in:
- lib/solve/solver.rb,
lib/solve/solver/serializer.rb,
lib/solve/solver/variable_row.rb,
lib/solve/solver/constraint_row.rb,
lib/solve/solver/variable_table.rb,
lib/solve/solver/constraint_table.rb
Defined Under Namespace
Classes: ConstraintRow, ConstraintTable, Serializer, VariableRow, VariableTable
Instance Attribute Summary collapse
-
#constraint_table ⇒ Object
readonly
Returns the value of attribute constraint_table.
- #demands(*args) ⇒ Object readonly
-
#domain ⇒ Object
readonly
Returns the value of attribute domain.
-
#graph ⇒ Solve::Graph
readonly
The world as we know it.
-
#possible_values ⇒ Object
readonly
Returns the value of attribute possible_values.
-
#ui ⇒ Object
readonly
Returns the value of attribute ui.
-
#variable_table ⇒ Object
readonly
Returns the value of attribute variable_table.
Class Method Summary collapse
-
.demand_key(demand) ⇒ Symbol
Create a key to identify a demand on a Solver.
-
.satisfy_all(constraints, versions) ⇒ Array<Solve::Version>
Returns all of the versions which satisfy all of the given constraints.
-
.satisfy_best(constraints, versions) ⇒ Solve::Version
Return the best version from the given list of versions for the given list of constraints.
Instance Method Summary collapse
-
#add_demand(demand) ⇒ Solve::Demand
(also: #demand)
Add a Solve::Demand to the collection of demands and return the added Solve::Demand.
- #has_demand?(demand) ⇒ Boolean
-
#initialize(graph, demands = Array.new, ui = nil) ⇒ Solver
constructor
A new instance of Solver.
- #remove_demand(demand) ⇒ Object
- #resolve ⇒ Hash
Constructor Details
#initialize(graph, demands = Array.new, ui = nil) ⇒ Solver
Returns a new instance of Solver.
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# File 'lib/solve/solver.rb', line 75 def initialize(graph, demands = Array.new, ui=nil) @graph = graph @demands = Hash.new @ui = ui.respond_to?(:say) ? ui : nil @domain = Hash.new @possible_values = Hash.new @constraint_table = ConstraintTable.new @variable_table = VariableTable.new Array(demands).each do |l_demand| demands(*l_demand) end end |
Instance Attribute Details
#constraint_table ⇒ Object (readonly)
Returns the value of attribute constraint_table.
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# File 'lib/solve/solver.rb', line 69 def constraint_table @constraint_table end |
#demands(name, constraint) ⇒ Solve::Demand (readonly) #demands(name) ⇒ Solve::Demand (readonly) #demands ⇒ Array<Solve::Demand> (readonly)
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# File 'lib/solve/solver.rb', line 153 def demands @demands end |
#domain ⇒ Object (readonly)
Returns the value of attribute domain.
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# File 'lib/solve/solver.rb', line 67 def domain @domain end |
#graph ⇒ Solve::Graph (readonly)
The world as we know it
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# File 'lib/solve/solver.rb', line 63 def graph @graph end |
#possible_values ⇒ Object (readonly)
Returns the value of attribute possible_values.
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# File 'lib/solve/solver.rb', line 70 def possible_values @possible_values end |
#ui ⇒ Object (readonly)
Returns the value of attribute ui.
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# File 'lib/solve/solver.rb', line 65 def ui @ui end |
#variable_table ⇒ Object (readonly)
Returns the value of attribute variable_table.
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# File 'lib/solve/solver.rb', line 68 def variable_table @variable_table end |
Class Method Details
.demand_key(demand) ⇒ Symbol
Create a key to identify a demand on a Solver.
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# File 'lib/solve/solver.rb', line 17 def demand_key(demand) "#{demand.name}-#{demand.constraint}".to_sym end |
.satisfy_all(constraints, versions) ⇒ Array<Solve::Version>
Returns all of the versions which satisfy all of the given constraints
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# File 'lib/solve/solver.rb', line 27 def satisfy_all(constraints, versions) constraints = Array(constraints).collect do |con| con.is_a?(Constraint) ? con : Constraint.new(con.to_s) end.uniq versions = Array(versions).collect do |ver| ver.is_a?(Version) ? ver : Version.new(ver.to_s) end.uniq versions.select do |ver| constraints.all? { |constraint| constraint.satisfies?(ver) } end end |
.satisfy_best(constraints, versions) ⇒ Solve::Version
Return the best version from the given list of versions for the given list of constraints
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# File 'lib/solve/solver.rb', line 49 def satisfy_best(constraints, versions) solution = satisfy_all(constraints, versions) if solution.empty? raise Errors::NoSolutionError end solution.sort.last end |
Instance Method Details
#add_demand(demand) ⇒ Solve::Demand Also known as: demand
Add a Solve::Demand to the collection of demands and return the added Solve::Demand. No change will be made if the demand is already a member of the collection.
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# File 'lib/solve/solver.rb', line 179 def add_demand(demand) unless has_demand?(demand) @demands[self.class.demand_key(demand)] = demand end demand end |
#has_demand?(demand) ⇒ Boolean
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# File 'lib/solve/solver.rb', line 198 def has_demand?(demand) @demands.has_key?(self.class.demand_key(demand)) end |
#remove_demand(demand) ⇒ Object
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# File 'lib/solve/solver.rb', line 189 def remove_demand(demand) if has_demand?(demand) @demands.delete(self.class.demand_key(demand)) end end |
#resolve ⇒ Hash
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# File 'lib/solve/solver.rb', line 91 def resolve trace("Attempting to find a solution") seed_demand_dependencies while unbound_variable = variable_table.first_unbound possible_values_for_unbound = possible_values_for(unbound_variable) trace("Searching for a value for #{unbound_variable.artifact}") trace("Constraints are") constraint_table.constraints_on_artifact(unbound_variable.artifact).each do |constraint| trace("\t#{constraint}") end trace("Possible values are #{possible_values_for_unbound}") while possible_value = possible_values_for_unbound.shift possible_artifact = graph.get_artifact(unbound_variable.artifact, possible_value.version) possible_dependencies = possible_artifact.dependencies all_ok = possible_dependencies.all? { |dependency| can_add_new_constraint?(dependency) } if all_ok trace("Attempting to use #{possible_artifact}") add_dependencies(possible_dependencies, possible_artifact) unbound_variable.bind(possible_value) break end end unless unbound_variable.bound? trace("Could not find an acceptable value for #{unbound_variable.artifact}") backtrack(unbound_variable) end end solution = {}.tap do |solution| variable_table.rows.each do |variable| solution[variable.artifact] = variable.value.version.to_s end end trace("Found Solution") trace(solution) solution end |