com.google.ortools.constraintsolver

Enum FirstSolutionStrategy.Value

java.lang.Object

java.lang.Enum<FirstSolutionStrategy.Value>

com.google.ortools.constraintsolver.FirstSolutionStrategy.Value

All Implemented Interfaces:

com.google.protobuf.Internal.EnumLite, com.google.protobuf.ProtocolMessageEnum, java.io.Serializable, java.lang.Comparable<FirstSolutionStrategy.Value>

Enclosing class:

FirstSolutionStrategy

public static enum FirstSolutionStrategy.Value
extends java.lang.Enum<FirstSolutionStrategy.Value>
implements com.google.protobuf.ProtocolMessageEnum

Protobuf enum operations_research.FirstSolutionStrategy.Value

Enum Constant Summary

Enum Constants

Enum Constant and Description
ALL_UNPERFORMED --- Path insertion heuristics --- Make all nodes inactive.
AUTOMATIC Lets the solver detect which strategy to use according to the model being solved.
BEST_INSERTION Iteratively build a solution by inserting the cheapest node at its cheapest position; the cost of insertion is based on the global cost function of the routing model.
CHRISTOFIDES Christofides algorithm (actually a variant of the Christofides algorithm using a maximal matching instead of a maximum matching, which does not guarantee the 3/2 factor of the approximation on a metric travelling salesman).
EVALUATOR_STRATEGY Same as PATH_CHEAPEST_ARC, except that arc costs are evaluated using the function passed to RoutingModel::SetFirstSolutionEvaluator() (cf. routing.h).
FIRST_UNBOUND_MIN_VALUE Select the first node with an unbound successor and connect it to the first available node.
GLOBAL_CHEAPEST_ARC --- Variable-based heuristics --- Iteratively connect two nodes which produce the cheapest route segment.
LOCAL_CHEAPEST_ARC Select the first node with an unbound successor and connect it to the node which produces the cheapest route segment.
LOCAL_CHEAPEST_COST_INSERTION Same as LOCAL_CHEAPEST_INSERTION except that the cost of insertion is based on the routing model cost function instead of arc costs only.
LOCAL_CHEAPEST_INSERTION Iteratively build a solution by inserting each node at its cheapest position; the cost of insertion is based on the arc cost function.
PARALLEL_CHEAPEST_INSERTION Iteratively build a solution by inserting the cheapest node at its cheapest position; the cost of insertion is based on the arc cost function.
PARALLEL_SAVINGS Parallel version of the Savings algorithm.
PATH_CHEAPEST_ARC --- Path addition heuristics --- Starting from a route "start" node, connect it to the node which produces the cheapest route segment, then extend the route by iterating on the last node added to the route.
PATH_MOST_CONSTRAINED_ARC Same as PATH_CHEAPEST_ARC, but arcs are evaluated with a comparison-based selector which will favor the most constrained arc first.
SAVINGS Savings algorithm (Clarke & Wright).
SEQUENTIAL_CHEAPEST_INSERTION Iteratively build a solution by constructing routes sequentially, for each route inserting the cheapest node at its cheapest position until the route is completed; the cost of insertion is based on the arc cost function.
SWEEP Sweep algorithm (Wren & Holliday).
UNRECOGNIZED
UNSET See the homonymous value in LocalSearchMetaheuristic.

Field Summary

Fields

Modifier and Type	Field and Description
static int	ALL_UNPERFORMED_VALUE --- Path insertion heuristics --- Make all nodes inactive.
static int	AUTOMATIC_VALUE Lets the solver detect which strategy to use according to the model being solved.
static int	BEST_INSERTION_VALUE Iteratively build a solution by inserting the cheapest node at its cheapest position; the cost of insertion is based on the global cost function of the routing model.
static int	CHRISTOFIDES_VALUE Christofides algorithm (actually a variant of the Christofides algorithm using a maximal matching instead of a maximum matching, which does not guarantee the 3/2 factor of the approximation on a metric travelling salesman).
static int	EVALUATOR_STRATEGY_VALUE Same as PATH_CHEAPEST_ARC, except that arc costs are evaluated using the function passed to RoutingModel::SetFirstSolutionEvaluator() (cf. routing.h).
static int	FIRST_UNBOUND_MIN_VALUE_VALUE Select the first node with an unbound successor and connect it to the first available node.
static int	GLOBAL_CHEAPEST_ARC_VALUE --- Variable-based heuristics --- Iteratively connect two nodes which produce the cheapest route segment.
static int	LOCAL_CHEAPEST_ARC_VALUE Select the first node with an unbound successor and connect it to the node which produces the cheapest route segment.
static int	LOCAL_CHEAPEST_COST_INSERTION_VALUE Same as LOCAL_CHEAPEST_INSERTION except that the cost of insertion is based on the routing model cost function instead of arc costs only.
static int	LOCAL_CHEAPEST_INSERTION_VALUE Iteratively build a solution by inserting each node at its cheapest position; the cost of insertion is based on the arc cost function.
static int	PARALLEL_CHEAPEST_INSERTION_VALUE Iteratively build a solution by inserting the cheapest node at its cheapest position; the cost of insertion is based on the arc cost function.
static int	PARALLEL_SAVINGS_VALUE Parallel version of the Savings algorithm.
static int	PATH_CHEAPEST_ARC_VALUE --- Path addition heuristics --- Starting from a route "start" node, connect it to the node which produces the cheapest route segment, then extend the route by iterating on the last node added to the route.
static int	PATH_MOST_CONSTRAINED_ARC_VALUE Same as PATH_CHEAPEST_ARC, but arcs are evaluated with a comparison-based selector which will favor the most constrained arc first.
static int	SAVINGS_VALUE Savings algorithm (Clarke & Wright).
static int	SEQUENTIAL_CHEAPEST_INSERTION_VALUE Iteratively build a solution by constructing routes sequentially, for each route inserting the cheapest node at its cheapest position until the route is completed; the cost of insertion is based on the arc cost function.
static int	SWEEP_VALUE Sweep algorithm (Wren & Holliday).
static int	UNSET_VALUE See the homonymous value in LocalSearchMetaheuristic.

Method Summary

Modifier and Type	Method and Description
static FirstSolutionStrategy.Value	forNumber(int value)
static com.google.protobuf.Descriptors.EnumDescriptor	getDescriptor()
com.google.protobuf.Descriptors.EnumDescriptor	getDescriptorForType()
int	getNumber()
com.google.protobuf.Descriptors.EnumValueDescriptor	getValueDescriptor()
static com.google.protobuf.Internal.EnumLiteMap<FirstSolutionStrategy.Value>	internalGetValueMap()
static FirstSolutionStrategy.Value	valueOf(com.google.protobuf.Descriptors.EnumValueDescriptor desc)
static FirstSolutionStrategy.Value	valueOf(int value) Deprecated. Use forNumber(int) instead.
static FirstSolutionStrategy.Value	valueOf(java.lang.String name) Returns the enum constant of this type with the specified name.
static FirstSolutionStrategy.Value[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

UNSET

public static final FirstSolutionStrategy.Value UNSET

 See the homonymous value in LocalSearchMetaheuristic.
 

UNSET = 0;

AUTOMATIC

public static final FirstSolutionStrategy.Value AUTOMATIC

 Lets the solver detect which strategy to use according to the model being
 solved.
 

AUTOMATIC = 15;

PATH_CHEAPEST_ARC

public static final FirstSolutionStrategy.Value PATH_CHEAPEST_ARC

 --- Path addition heuristics ---
 Starting from a route "start" node, connect it to the node which produces
 the cheapest route segment, then extend the route by iterating on the
 last node added to the route.
 

PATH_CHEAPEST_ARC = 3;

PATH_MOST_CONSTRAINED_ARC

public static final FirstSolutionStrategy.Value PATH_MOST_CONSTRAINED_ARC

 Same as PATH_CHEAPEST_ARC, but arcs are evaluated with a comparison-based
 selector which will favor the most constrained arc first. To assign a
 selector to the routing model, see
 RoutingModel::ArcIsMoreConstrainedThanArc() in routing.h for details.
 

PATH_MOST_CONSTRAINED_ARC = 4;

EVALUATOR_STRATEGY

public static final FirstSolutionStrategy.Value EVALUATOR_STRATEGY

 Same as PATH_CHEAPEST_ARC, except that arc costs are evaluated using the
 function passed to RoutingModel::SetFirstSolutionEvaluator()
 (cf. routing.h).
 

EVALUATOR_STRATEGY = 5;

SAVINGS

public static final FirstSolutionStrategy.Value SAVINGS

 Savings algorithm (Clarke & Wright).
 Reference: Clarke, G. & Wright, J.W.:
 "Scheduling of Vehicles from a Central Depot to a Number of Delivery
 Points", Operations Research, Vol. 12, 1964, pp. 568-581
 

SAVINGS = 10;

PARALLEL_SAVINGS

public static final FirstSolutionStrategy.Value PARALLEL_SAVINGS

 Parallel version of the Savings algorithm.
 Instead of extending a single route until it is no longer possible,
 the parallel version iteratively considers the next most improving
 feasible saving and possibly builds several routes in parallel.
 

PARALLEL_SAVINGS = 17;

SWEEP

public static final FirstSolutionStrategy.Value SWEEP

 Sweep algorithm (Wren & Holliday).
 Reference: Anthony Wren & Alan Holliday: Computer Scheduling of Vehicles
 from One or More Depots to a Number of Delivery Points Operational
 Research Quarterly (1970-1977),
 Vol. 23, No. 3 (Sep., 1972), pp. 333-344
 

SWEEP = 11;

CHRISTOFIDES

public static final FirstSolutionStrategy.Value CHRISTOFIDES

 Christofides algorithm (actually a variant of the Christofides algorithm
 using a maximal matching instead of a maximum matching, which does
 not guarantee the 3/2 factor of the approximation on a metric travelling
 salesman). Works on generic vehicle routing models by extending a route
 until no nodes can be inserted on it.
 Reference: Nicos Christofides, Worst-case analysis of a new heuristic for
 the travelling salesman problem, Report 388, Graduate School of
 Industrial Administration, CMU, 1976.
 

CHRISTOFIDES = 13;

ALL_UNPERFORMED

public static final FirstSolutionStrategy.Value ALL_UNPERFORMED

 --- Path insertion heuristics ---
 Make all nodes inactive. Only finds a solution if nodes are optional (are
 element of a disjunction constraint with a finite penalty cost).
 

ALL_UNPERFORMED = 6;

BEST_INSERTION

public static final FirstSolutionStrategy.Value BEST_INSERTION

 Iteratively build a solution by inserting the cheapest node at its
 cheapest position; the cost of insertion is based on the global cost
 function of the routing model. As of 2/2012, only works on models with
 optional nodes (with finite penalty costs).
 

BEST_INSERTION = 7;

PARALLEL_CHEAPEST_INSERTION

public static final FirstSolutionStrategy.Value PARALLEL_CHEAPEST_INSERTION

 Iteratively build a solution by inserting the cheapest node at its
 cheapest position; the cost of insertion is based on the arc cost
 function. Is faster than BEST_INSERTION.
 

PARALLEL_CHEAPEST_INSERTION = 8;

SEQUENTIAL_CHEAPEST_INSERTION

public static final FirstSolutionStrategy.Value SEQUENTIAL_CHEAPEST_INSERTION

 Iteratively build a solution by constructing routes sequentially, for
 each route inserting the cheapest node at its cheapest position until the
 route is completed; the cost of insertion is based on the arc cost
 function. Is faster than PARALLEL_CHEAPEST_INSERTION.
 

SEQUENTIAL_CHEAPEST_INSERTION = 14;

LOCAL_CHEAPEST_INSERTION

public static final FirstSolutionStrategy.Value LOCAL_CHEAPEST_INSERTION

 Iteratively build a solution by inserting each node at its cheapest
 position; the cost of insertion is based on the arc cost function.
 Differs from PARALLEL_CHEAPEST_INSERTION by the node selected for
 insertion; here nodes are considered in decreasing order of distance to
 the start/ends of the routes, i.e. farthest nodes are inserted first.
 Is faster than SEQUENTIAL_CHEAPEST_INSERTION.
 

LOCAL_CHEAPEST_INSERTION = 9;

LOCAL_CHEAPEST_COST_INSERTION

public static final FirstSolutionStrategy.Value LOCAL_CHEAPEST_COST_INSERTION

 Same as LOCAL_CHEAPEST_INSERTION except that the cost of insertion is
 based on the routing model cost function instead of arc costs only.
 

LOCAL_CHEAPEST_COST_INSERTION = 16;

GLOBAL_CHEAPEST_ARC

public static final FirstSolutionStrategy.Value GLOBAL_CHEAPEST_ARC

 --- Variable-based heuristics ---
 Iteratively connect two nodes which produce the cheapest route segment.
 

GLOBAL_CHEAPEST_ARC = 1;

LOCAL_CHEAPEST_ARC

public static final FirstSolutionStrategy.Value LOCAL_CHEAPEST_ARC

 Select the first node with an unbound successor and connect it to the
 node which produces the cheapest route segment.
 

LOCAL_CHEAPEST_ARC = 2;

FIRST_UNBOUND_MIN_VALUE

public static final FirstSolutionStrategy.Value FIRST_UNBOUND_MIN_VALUE

 Select the first node with an unbound successor and connect it to the
 first available node.
 This is equivalent to the CHOOSE_FIRST_UNBOUND strategy combined with
 ASSIGN_MIN_VALUE (cf. constraint_solver.h).
 

FIRST_UNBOUND_MIN_VALUE = 12;

UNRECOGNIZED

public static final FirstSolutionStrategy.Value UNRECOGNIZED

Field Detail

UNSET_VALUE

public static final int UNSET_VALUE

 See the homonymous value in LocalSearchMetaheuristic.
 

UNSET = 0;

See Also:

Constant Field Values

AUTOMATIC_VALUE

public static final int AUTOMATIC_VALUE

 Lets the solver detect which strategy to use according to the model being
 solved.
 

AUTOMATIC = 15;

See Also:

Constant Field Values

PATH_CHEAPEST_ARC_VALUE

public static final int PATH_CHEAPEST_ARC_VALUE

 --- Path addition heuristics ---
 Starting from a route "start" node, connect it to the node which produces
 the cheapest route segment, then extend the route by iterating on the
 last node added to the route.
 

PATH_CHEAPEST_ARC = 3;

See Also:

Constant Field Values

PATH_MOST_CONSTRAINED_ARC_VALUE

public static final int PATH_MOST_CONSTRAINED_ARC_VALUE

 Same as PATH_CHEAPEST_ARC, but arcs are evaluated with a comparison-based
 selector which will favor the most constrained arc first. To assign a
 selector to the routing model, see
 RoutingModel::ArcIsMoreConstrainedThanArc() in routing.h for details.
 

PATH_MOST_CONSTRAINED_ARC = 4;

See Also:

Constant Field Values

EVALUATOR_STRATEGY_VALUE

public static final int EVALUATOR_STRATEGY_VALUE

 Same as PATH_CHEAPEST_ARC, except that arc costs are evaluated using the
 function passed to RoutingModel::SetFirstSolutionEvaluator()
 (cf. routing.h).
 

EVALUATOR_STRATEGY = 5;

See Also:

Constant Field Values

SAVINGS_VALUE

public static final int SAVINGS_VALUE

 Savings algorithm (Clarke & Wright).
 Reference: Clarke, G. & Wright, J.W.:
 "Scheduling of Vehicles from a Central Depot to a Number of Delivery
 Points", Operations Research, Vol. 12, 1964, pp. 568-581
 

SAVINGS = 10;

See Also:

Constant Field Values

PARALLEL_SAVINGS_VALUE

public static final int PARALLEL_SAVINGS_VALUE

 Parallel version of the Savings algorithm.
 Instead of extending a single route until it is no longer possible,
 the parallel version iteratively considers the next most improving
 feasible saving and possibly builds several routes in parallel.
 

PARALLEL_SAVINGS = 17;

See Also:

Constant Field Values

SWEEP_VALUE

public static final int SWEEP_VALUE

 Sweep algorithm (Wren & Holliday).
 Reference: Anthony Wren & Alan Holliday: Computer Scheduling of Vehicles
 from One or More Depots to a Number of Delivery Points Operational
 Research Quarterly (1970-1977),
 Vol. 23, No. 3 (Sep., 1972), pp. 333-344
 

SWEEP = 11;

See Also:

Constant Field Values

CHRISTOFIDES_VALUE

public static final int CHRISTOFIDES_VALUE

 Christofides algorithm (actually a variant of the Christofides algorithm
 using a maximal matching instead of a maximum matching, which does
 not guarantee the 3/2 factor of the approximation on a metric travelling
 salesman). Works on generic vehicle routing models by extending a route
 until no nodes can be inserted on it.
 Reference: Nicos Christofides, Worst-case analysis of a new heuristic for
 the travelling salesman problem, Report 388, Graduate School of
 Industrial Administration, CMU, 1976.
 

CHRISTOFIDES = 13;

See Also:

Constant Field Values

ALL_UNPERFORMED_VALUE

public static final int ALL_UNPERFORMED_VALUE

 --- Path insertion heuristics ---
 Make all nodes inactive. Only finds a solution if nodes are optional (are
 element of a disjunction constraint with a finite penalty cost).
 

ALL_UNPERFORMED = 6;

See Also:

Constant Field Values

BEST_INSERTION_VALUE

public static final int BEST_INSERTION_VALUE

 Iteratively build a solution by inserting the cheapest node at its
 cheapest position; the cost of insertion is based on the global cost
 function of the routing model. As of 2/2012, only works on models with
 optional nodes (with finite penalty costs).
 

BEST_INSERTION = 7;

See Also:

Constant Field Values

PARALLEL_CHEAPEST_INSERTION_VALUE

public static final int PARALLEL_CHEAPEST_INSERTION_VALUE

 Iteratively build a solution by inserting the cheapest node at its
 cheapest position; the cost of insertion is based on the arc cost
 function. Is faster than BEST_INSERTION.
 

PARALLEL_CHEAPEST_INSERTION = 8;

See Also:

Constant Field Values

SEQUENTIAL_CHEAPEST_INSERTION_VALUE

public static final int SEQUENTIAL_CHEAPEST_INSERTION_VALUE

 Iteratively build a solution by constructing routes sequentially, for
 each route inserting the cheapest node at its cheapest position until the
 route is completed; the cost of insertion is based on the arc cost
 function. Is faster than PARALLEL_CHEAPEST_INSERTION.
 

SEQUENTIAL_CHEAPEST_INSERTION = 14;

See Also:

Constant Field Values

LOCAL_CHEAPEST_INSERTION_VALUE

public static final int LOCAL_CHEAPEST_INSERTION_VALUE

 Iteratively build a solution by inserting each node at its cheapest
 position; the cost of insertion is based on the arc cost function.
 Differs from PARALLEL_CHEAPEST_INSERTION by the node selected for
 insertion; here nodes are considered in decreasing order of distance to
 the start/ends of the routes, i.e. farthest nodes are inserted first.
 Is faster than SEQUENTIAL_CHEAPEST_INSERTION.
 

LOCAL_CHEAPEST_INSERTION = 9;

See Also:

Constant Field Values

LOCAL_CHEAPEST_COST_INSERTION_VALUE

public static final int LOCAL_CHEAPEST_COST_INSERTION_VALUE

 Same as LOCAL_CHEAPEST_INSERTION except that the cost of insertion is
 based on the routing model cost function instead of arc costs only.
 

LOCAL_CHEAPEST_COST_INSERTION = 16;

See Also:

Constant Field Values

GLOBAL_CHEAPEST_ARC_VALUE

public static final int GLOBAL_CHEAPEST_ARC_VALUE

 --- Variable-based heuristics ---
 Iteratively connect two nodes which produce the cheapest route segment.
 

GLOBAL_CHEAPEST_ARC = 1;

See Also:

Constant Field Values

LOCAL_CHEAPEST_ARC_VALUE

public static final int LOCAL_CHEAPEST_ARC_VALUE

 Select the first node with an unbound successor and connect it to the
 node which produces the cheapest route segment.
 

LOCAL_CHEAPEST_ARC = 2;

See Also:

Constant Field Values

FIRST_UNBOUND_MIN_VALUE_VALUE

public static final int FIRST_UNBOUND_MIN_VALUE_VALUE

 Select the first node with an unbound successor and connect it to the
 first available node.
 This is equivalent to the CHOOSE_FIRST_UNBOUND strategy combined with
 ASSIGN_MIN_VALUE (cf. constraint_solver.h).
 

FIRST_UNBOUND_MIN_VALUE = 12;

See Also:

Constant Field Values

Method Detail

values

public static FirstSolutionStrategy.Value[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (FirstSolutionStrategy.Value c : FirstSolutionStrategy.Value.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static FirstSolutionStrategy.Value valueOf(java.lang.String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null

getNumber

public final int getNumber()

Specified by:

getNumber in interface com.google.protobuf.Internal.EnumLite

Specified by:

getNumber in interface com.google.protobuf.ProtocolMessageEnum

valueOf

@Deprecated
public static FirstSolutionStrategy.Value valueOf(int value)

Deprecated. Use forNumber(int) instead.

Parameters:

value - The numeric wire value of the corresponding enum entry.

Returns:

The enum associated with the given numeric wire value.

forNumber

public static FirstSolutionStrategy.Value forNumber(int value)

Parameters:

value - The numeric wire value of the corresponding enum entry.

Returns:

The enum associated with the given numeric wire value.

internalGetValueMap

public static com.google.protobuf.Internal.EnumLiteMap<FirstSolutionStrategy.Value> internalGetValueMap()

getValueDescriptor

public final com.google.protobuf.Descriptors.EnumValueDescriptor getValueDescriptor()

Specified by:

getValueDescriptor in interface com.google.protobuf.ProtocolMessageEnum

getDescriptorForType

public final com.google.protobuf.Descriptors.EnumDescriptor getDescriptorForType()

Specified by:

getDescriptorForType in interface com.google.protobuf.ProtocolMessageEnum

getDescriptor

public static final com.google.protobuf.Descriptors.EnumDescriptor getDescriptor()

valueOf

public static FirstSolutionStrategy.Value valueOf(com.google.protobuf.Descriptors.EnumValueDescriptor desc)