autopilot

package
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 Go to latest Published: Aug 22, 2020 License: MIT Imports: 23 Imported by: 0

Documentation

Index

Constants

View Source 
const DefaultConfTarget = 3

DefaultConfTarget is the default confirmation target for autopilot channels. TODO(halseth): possibly make dynamic, going aggressive->lax as more channels are opened.

Variables

View Source 
var (

	// AvailableHeuristics is a map that holds the name of available
	// heuristics to the actual heuristic for easy lookup. It will be
	// filled during init().
	AvailableHeuristics = make(map[string]AttachmentHeuristic)
)
View Source 
var ErrNoPositive = errors.New("no positive weights left")

ErrNoPositive is returned from weightedChoice when there are no positive weights left to choose from.

Functions

func DisableLog 

func DisableLog()

DisableLog disables all library log output. Logging output is disabled by default until UseLogger is called.

func Median 

func Median(vals []ltcutil.Amount) ltcutil.Amount

Median returns the median value in the slice of Amounts.

func UseLogger 

func UseLogger(logger btclog.Logger)

UseLogger uses a specified Logger to output package logging info. This should be used in preference to SetLogWriter if the caller is also using btclog.

Types

type Agent 

type Agent struct {
	// contains filtered or unexported fields
}

Agent implements a closed-loop control system which seeks to autonomously optimize the allocation of satoshis within channels throughput the network's channel graph. An agent is configurable by swapping out different AttachmentHeuristic strategies. The agent uses external signals such as the wallet balance changing, or new channels being opened/closed for the local node as an indicator to re-examine its internal state, and the amount of available funds in order to make updated decisions w.r.t the channel graph. The Agent will automatically open, close, and splice in/out channel as necessary for it to step closer to its optimal state.

TODO(roasbeef): prob re-word

func New 

func New(cfg Config, initialState []Channel) (*Agent, error)

New creates a new instance of the Agent instantiated using the passed configuration and initial channel state. The initial channel state slice should be populated with the set of Channels that are currently opened by the backing Lightning Node.

func (*Agent) OnBalanceChange 

func (a *Agent) OnBalanceChange()

OnBalanceChange is a callback that should be executed each time the balance of the backing wallet changes.

func (*Agent) OnChannelClose 

func (a *Agent) OnChannelClose(closedChans ...lnwire.ShortChannelID)

OnChannelClose is a callback that should be executed each time a prior channel has been closed for any reason. This includes regular closes, force closes, and channel breaches.

func (*Agent) OnChannelOpen 

func (a *Agent) OnChannelOpen(c Channel)

OnChannelOpen is a callback that should be executed each time a new channel is manually opened by the user or any system outside the autopilot agent.

func (*Agent) OnChannelOpenFailure 

func (a *Agent) OnChannelOpenFailure()

OnChannelOpenFailure is a callback that should be executed when the autopilot has attempted to open a channel, but failed. In this case we can retry channel creation with a different node.

func (*Agent) OnChannelPendingOpen 

func (a *Agent) OnChannelPendingOpen()

OnChannelPendingOpen is a callback that should be executed each time a new channel is opened, either by the agent or an external subsystems, but is still pending.

func (*Agent) OnHeuristicUpdate 

func (a *Agent) OnHeuristicUpdate(h AttachmentHeuristic)

OnHeuristicUpdate is a method called when a heuristic has been updated, to trigger the agent to do a new state assessment.

func (*Agent) OnNodeUpdates 

func (a *Agent) OnNodeUpdates()

OnNodeUpdates is a callback that should be executed each time our channel graph has new nodes or their node announcements are updated.

func (*Agent) Start 

func (a *Agent) Start() error

Start starts the agent along with any goroutines it needs to perform its normal duties.

func (*Agent) Stop 

func (a *Agent) Stop() error

Stop signals the Agent to gracefully shutdown. This function will block until all goroutines have exited.

type AgentConstraints 

type AgentConstraints interface {
	// ChannelBudget should, given the passed parameters, return whether
	// more channels can be be opened while still staying within the set
	// constraints. If the constraints allow us to open more channels, then
	// the first return value will represent the amount of additional funds
	// available towards creating channels. The second return value is the
	// exact *number* of additional channels available.
	ChannelBudget(chans []Channel, balance ltcutil.Amount) (
		ltcutil.Amount, uint32)

	// MaxPendingOpens returns the maximum number of pending channel
	// establishment goroutines that can be lingering. We cap this value in
	// order to control the level of parallelism caused by the autopilot
	// agent.
	MaxPendingOpens() uint16

	// MinChanSize returns the smallest channel that the autopilot agent
	// should create.
	MinChanSize() ltcutil.Amount

	// MaxChanSize returns largest channel that the autopilot agent should
	// create.
	MaxChanSize() ltcutil.Amount
}

AgentConstraints is an interface the agent will query to determine what limits it will need to stay inside when opening channels.

func NewConstraints 

func NewConstraints(minChanSize, maxChanSize ltcutil.Amount, chanLimit,
	maxPendingOpens uint16, allocation float64) AgentConstraints

NewConstraints returns a new AgentConstraints with the given limits.

type AttachmentDirective 

type AttachmentDirective struct {
	// NodeID is the serialized compressed pubkey of the target node for
	// this attachment directive. It can be identified by its public key,
	// and therefore can be used along with a ChannelOpener implementation
	// to execute the directive.
	NodeID NodeID

	// ChanAmt is the size of the channel that should be opened, expressed
	// in satoshis.
	ChanAmt ltcutil.Amount

	// Addrs is a list of addresses that the target peer may be reachable
	// at.
	Addrs []net.Addr
}

AttachmentDirective describes a channel attachment proscribed by an AttachmentHeuristic. It details to which node a channel should be created to, and also the parameters which should be used in the channel creation.

type AttachmentHeuristic 

type AttachmentHeuristic interface {
	// Name returns the name of this heuristic.
	Name() string

	// NodeScores is a method that given the current channel graph and
	// current set of local channels, scores the given nodes according to
	// the preference of opening a channel of the given size with them. The
	// returned channel candidates maps the NodeID to a NodeScore for the
	// node.
	//
	// The returned scores will be in the range [0, 1.0], where 0 indicates
	// no improvement in connectivity if a channel is opened to this node,
	// while 1.0 is the maximum possible improvement in connectivity. The
	// implementation of this interface must return scores in this range to
	// properly allow the autopilot agent to make a reasonable choice based
	// on the score from multiple heuristics.
	//
	// NOTE: A NodeID not found in the returned map is implicitly given a
	// score of 0.
	NodeScores(g ChannelGraph, chans []Channel,
		chanSize ltcutil.Amount, nodes map[NodeID]struct{}) (
		map[NodeID]*NodeScore, error)
}

AttachmentHeuristic is one of the primary interfaces within this package. Implementations of this interface will be used to implement a control system which automatically regulates channels of a particular agent, attempting to optimize channels opened/closed based on various heuristics. The purpose of the interface is to allow an auto-pilot agent to decide if it needs more channels, and if so, which exact channels should be opened.

type BetweennessCentrality 

type BetweennessCentrality struct {
	// contains filtered or unexported fields
}

BetweennessCentrality is a NodeMetric that calculates node betweenness centrality using Brandes' algorithm. Betweenness centrality for each node is the number of shortest paths passing trough that node, not counting shortest paths starting or ending at that node. This is a useful metric to measure control of individual nodes over the whole network.

func NewBetweennessCentralityMetric 

func NewBetweennessCentralityMetric(workers int) (*BetweennessCentrality, error)

NewBetweennessCentralityMetric creates a new BetweennessCentrality instance. Users can specify the number of workers to use for calculating centrality.

func (*BetweennessCentrality) GetMetric 

func (bc *BetweennessCentrality) GetMetric(normalize bool) map[NodeID]float64

GetMetric returns the current centrality values for each node indexed by node id.

func (*BetweennessCentrality) Name 

func (bc *BetweennessCentrality) Name() string

Name returns the name of the metric.

func (*BetweennessCentrality) Refresh 

func (bc *BetweennessCentrality) Refresh(graph ChannelGraph) error

Refresh recaculates and stores centrality values.

type Channel 

type Channel struct {
	// ChanID is the short channel ID for this channel as defined within
	// BOLT-0007.
	ChanID lnwire.ShortChannelID

	// Capacity is the capacity of the channel expressed in satoshis.
	Capacity ltcutil.Amount

	// FundedAmt is the amount the local node funded into the target
	// channel.
	//
	// TODO(roasbeef): need this?
	FundedAmt ltcutil.Amount

	// Node is the peer that this channel has been established with.
	Node NodeID
}

Channel is a simple struct which contains relevant details of a particular channel within the channel graph. The fields in this struct may be used a signals for various AttachmentHeuristic implementations.

type ChannelController 

type ChannelController interface {
	// OpenChannel opens a channel to a target peer, using at most amt
	// funds. This means that the resulting channel capacity might be
	// slightly less to account for fees. This function should un-block
	// immediately after the funding transaction that marks the channel
	// open has been broadcast.
	OpenChannel(target *btcec.PublicKey, amt ltcutil.Amount) error

	// CloseChannel attempts to close out the target channel.
	//
	// TODO(roasbeef): add force option?
	CloseChannel(chanPoint *wire.OutPoint) error

	// SpliceIn attempts to add additional funds to the target channel via
	// a splice in mechanism. The new channel with an updated capacity
	// should be returned.
	SpliceIn(chanPoint *wire.OutPoint, amt ltcutil.Amount) (*Channel, error)

	// SpliceOut attempts to remove funds from an existing channels using a
	// splice out mechanism. The removed funds from the channel should be
	// returned to an output under the control of the backing wallet.
	SpliceOut(chanPoint *wire.OutPoint, amt ltcutil.Amount) (*Channel, error)
}

ChannelController is a simple interface that allows an auto-pilot agent to open a channel within the graph to a target peer, close targeted channels, or add/remove funds from existing channels via a splice in/out mechanisms.

type ChannelEdge 

type ChannelEdge struct {
	// Channel contains the attributes of this channel.
	Channel

	// Peer is the peer that this channel creates an edge to in the channel
	// graph.
	Peer Node
}

ChannelEdge is a struct that holds details concerning a channel, but also contains a reference to the Node that this channel connects to as a directed edge within the graph. The existence of this reference to the connected node will allow callers to traverse the graph in an object-oriented manner.

type ChannelGraph 

type ChannelGraph interface {
	// ForEachNode is a higher-order function that should be called once
	// for each connected node within the channel graph. If the passed
	// callback returns an error, then execution should be terminated.
	ForEachNode(func(Node) error) error
}

ChannelGraph in an interface that represents a traversable channel graph. The autopilot agent will use this interface as its source of graph traits in order to make decisions concerning which channels should be opened, and to whom.

TODO(roasbeef): abstract??

func ChannelGraphFromDatabase 

func ChannelGraphFromDatabase(db *channeldb.ChannelGraph) ChannelGraph

ChannelGraphFromDatabase returns an instance of the autopilot.ChannelGraph backed by a live, open channeldb instance.

type Config 

type Config struct {
	// Self is the identity public key of the Lightning Network node that
	// is being driven by the agent. This is used to ensure that we don't
	// accidentally attempt to open a channel with ourselves.
	Self *btcec.PublicKey

	// Heuristic is an attachment heuristic which will govern to whom we
	// open channels to, and also what those channels look like in terms of
	// desired capacity. The Heuristic will take into account the current
	// state of the graph, our set of open channels, and the amount of
	// available funds when determining how channels are to be opened.
	// Additionally, a heuristic make also factor in extra-graph
	// information in order to make more pertinent recommendations.
	Heuristic AttachmentHeuristic

	// ChanController is an interface that is able to directly manage the
	// creation, closing and update of channels within the network.
	ChanController ChannelController

	// ConnectToPeer attempts to connect to the peer using one of its
	// advertised addresses. The boolean returned signals whether the peer
	// was already connected.
	ConnectToPeer func(*btcec.PublicKey, []net.Addr) (bool, error)

	// DisconnectPeer attempts to disconnect the peer with the given public
	// key.
	DisconnectPeer func(*btcec.PublicKey) error

	// WalletBalance is a function closure that should return the current
	// available balance of the backing wallet.
	WalletBalance func() (ltcutil.Amount, error)

	// Graph is an abstract channel graph that the Heuristic and the Agent
	// will use to make decisions w.r.t channel allocation and placement
	// within the graph.
	Graph ChannelGraph

	// Constraints is the set of constraints the autopilot must adhere to
	// when opening channels.
	Constraints AgentConstraints
}

Config couples all the items that an autopilot agent needs to function. All items within the struct MUST be populated for the Agent to be able to carry out its duties.

type ExternalScoreAttachment 

type ExternalScoreAttachment struct {
	sync.Mutex
	// contains filtered or unexported fields
}

ExternalScoreAttachment is an implementation of the AttachmentHeuristic interface that allows an external source to provide it with node scores.

func NewExternalScoreAttachment 

func NewExternalScoreAttachment() *ExternalScoreAttachment

NewExternalScoreAttachment creates a new instance of an ExternalScoreAttachment.

func (*ExternalScoreAttachment) Name 

func (s *ExternalScoreAttachment) Name() string

Name returns the name of this heuristic.

NOTE: This is a part of the AttachmentHeuristic interface.

func (*ExternalScoreAttachment) NodeScores 

func (s *ExternalScoreAttachment) NodeScores(g ChannelGraph, chans []Channel,
	chanSize ltcutil.Amount, nodes map[NodeID]struct{}) (
	map[NodeID]*NodeScore, error)

NodeScores is a method that given the current channel graph and current set of local channels, scores the given nodes according to the preference of opening a channel of the given size with them. The returned channel candidates maps the NodeID to a NodeScore for the node.

The returned scores will be in the range [0, 1.0], where 0 indicates no improvement in connectivity if a channel is opened to this node, while 1.0 is the maximum possible improvement in connectivity.

The scores are determined by checking the internal node scores list. Nodes not known will get a score of 0.

NOTE: This is a part of the AttachmentHeuristic interface.

func (*ExternalScoreAttachment) SetNodeScores 

func (s *ExternalScoreAttachment) SetNodeScores(targetHeuristic string,
	newScores map[NodeID]float64) (bool, error)

SetNodeScores is used to set the internal map from NodeIDs to scores. The passed scores must be in the range [0, 1.0]. The fist parameter is the name of the targeted heuristic, to allow recursively target specific sub-heuristics. The returned boolean indicates whether the targeted heuristic was found.

NOTE: This is a part of the ScoreSettable interface.

type HeuristicScores 

type HeuristicScores map[string]map[NodeID]float64

HeuristicScores is an alias for a map that maps heuristic names to a map of scores for pubkeys.

type Manager 

type Manager struct {
	sync.Mutex
	// contains filtered or unexported fields
}

Manager is struct that manages an autopilot agent, making it possible to enable and disable it at will, and hand it relevant external information. It implements the autopilot grpc service, which is used to get data about the running autopilot, and give it relevant information.

func NewManager 

func NewManager(cfg *ManagerCfg) (*Manager, error)

NewManager creates a new instance of the Manager from the passed config.

func (*Manager) IsActive 

func (m *Manager) IsActive() bool

IsActive returns whether the autopilot agent is currently active.

func (*Manager) QueryHeuristics 

func (m *Manager) QueryHeuristics(nodes []NodeID, localState bool) (
	HeuristicScores, error)

QueryHeuristics queries the available autopilot heuristics for node scores.

func (*Manager) SetNodeScores 

func (m *Manager) SetNodeScores(name string, scores map[NodeID]float64) error

SetNodeScores is used to set the scores of the given heuristic, if it is active, and ScoreSettable.

func (*Manager) Start 

func (m *Manager) Start() error

Start starts the Manager.

func (*Manager) StartAgent 

func (m *Manager) StartAgent() error

StartAgent creates and starts an autopilot agent from the Manager's config.

func (*Manager) Stop 

func (m *Manager) Stop() error

Stop stops the Manager. If an autopilot agent is active, it will also be stopped.

func (*Manager) StopAgent 

func (m *Manager) StopAgent() error

StopAgent stops any active autopilot agent.

type ManagerCfg 

type ManagerCfg struct {
	// Self is the public key of the lnd instance. It is used to making
	// sure the autopilot is not opening channels to itself.
	Self *btcec.PublicKey

	// PilotCfg is the config of the autopilot agent managed by the
	// Manager.
	PilotCfg *Config

	// ChannelState is a function closure that returns the current set of
	// channels managed by this node.
	ChannelState func() ([]Channel, error)

	// SubscribeTransactions is used to get a subscription for transactions
	// relevant to this node's wallet.
	SubscribeTransactions func() (lnwallet.TransactionSubscription, error)

	// SubscribeTopology is used to get a subscription for topology changes
	// on the network.
	SubscribeTopology func() (*routing.TopologyClient, error)
}

ManagerCfg houses a set of values and methods that is passed to the Manager for it to properly manage its autopilot agent.

type Node 

type Node interface {
	// PubKey is the identity public key of the node. This will be used to
	// attempt to target a node for channel opening by the main autopilot
	// agent. The key will be returned in serialized compressed format.
	PubKey() [33]byte

	// Addrs returns a slice of publicly reachable public TCP addresses
	// that the peer is known to be listening on.
	Addrs() []net.Addr

	// ForEachChannel is a higher-order function that will be used to
	// iterate through all edges emanating from/to the target node. For
	// each active channel, this function should be called with the
	// populated ChannelEdge that describes the active channel.
	ForEachChannel(func(ChannelEdge) error) error
}

Node node is an interface which represents n abstract vertex within the channel graph. All nodes should have at least a single edge to/from them within the graph.

TODO(roasbeef): combine with routing.ChannelGraphSource

type NodeID 

type NodeID [33]byte

NodeID is a simple type that holds an EC public key serialized in compressed format.

func NewNodeID 

func NewNodeID(pub *btcec.PublicKey) NodeID

NewNodeID creates a new nodeID from a passed public key.

type NodeMetric 

type NodeMetric interface {
	// Name returns the unique name of this metric.
	Name() string

	// Refresh refreshes the metric values based on the current graph.
	Refresh(graph ChannelGraph) error

	// GetMetric returns the latest value of this metric. Values in the
	// map are per node and can be in arbitrary domain. If normalize is
	// set to true, then the returned values are normalized to either
	// [0, 1] or [-1, 1] depending on the metric.
	GetMetric(normalize bool) map[NodeID]float64
}

NodeMetric is a common interface for all graph metrics that are not directly used as autopilot node scores but may be used in compositional heuristics or statistical information exposed to users.

type NodeScore 

type NodeScore struct {
	// NodeID is the serialized compressed pubkey of the node that is being
	// scored.
	NodeID NodeID

	// Score is the score given by the heuristic for opening a channel of
	// the given size to this node.
	Score float64
}

NodeScore is a tuple mapping a NodeID to a score indicating the preference of opening a channel with it.

type PrefAttachment 

type PrefAttachment struct {
}

PrefAttachment is an implementation of the AttachmentHeuristic interface that implement a non-linear preferential attachment heuristic. This means that given a threshold to allocate to automatic channel establishment, the heuristic will attempt to favor connecting to nodes which already have a set amount of links, selected by sampling from a power law distribution. The attachment is non-linear in that it favors nodes with a higher in-degree but less so than regular linear preferential attachment. As a result, this creates smaller and less clusters than regular linear preferential attachment.

TODO(roasbeef): BA, with k=-3

func NewPrefAttachment 

func NewPrefAttachment() *PrefAttachment

NewPrefAttachment creates a new instance of a PrefAttachment heuristic.

func (*PrefAttachment) Name 

func (p *PrefAttachment) Name() string

Name returns the name of this heuristic.

NOTE: This is a part of the AttachmentHeuristic interface.

func (*PrefAttachment) NodeScores 

func (p *PrefAttachment) NodeScores(g ChannelGraph, chans []Channel,
	chanSize ltcutil.Amount, nodes map[NodeID]struct{}) (
	map[NodeID]*NodeScore, error)

NodeScores is a method that given the current channel graph and current set of local channels, scores the given nodes according to the preference of opening a channel of the given size with them. The returned channel candidates maps the NodeID to a NodeScore for the node.

The heuristic employed by this method is one that attempts to promote a scale-free network globally, via local attachment preferences for new nodes joining the network with an amount of available funds to be allocated to channels. Specifically, we consider the degree of each node (and the flow in/out of the node available via its open channels) and utilize the Barabási–Albert model to drive our recommended attachment heuristics. If implemented globally for each new participant, this results in a channel graph that is scale-free and follows a power law distribution with k=-3.

To avoid assigning a high score to nodes with a large number of small channels, we only count channels at least as large as a given fraction of the graph's median channel size.

The returned scores will be in the range [0.0, 1.0], where higher scores are given to nodes already having high connectivity in the graph.

NOTE: This is a part of the AttachmentHeuristic interface.

type ScoreSettable 

type ScoreSettable interface {
	// SetNodeScores is used to set the internal map from NodeIDs to
	// scores. The passed scores must be in the range [0, 1.0]. The fist
	// parameter is the name of the targeted heuristic, to allow
	// recursively target specific sub-heuristics. The returned boolean
	// indicates whether the targeted heuristic was found.
	SetNodeScores(string, map[NodeID]float64) (bool, error)
}

ScoreSettable is an interface that indicates that the scores returned by the heuristic can be mutated by an external caller. The ExternalScoreAttachment currently implements this interface, and so should any heuristic that is using the ExternalScoreAttachment as a sub-heuristic, or keeps their own internal list of mutable scores, to allow access to setting the internal scores.

type SimpleGraph 

type SimpleGraph struct {
	// Nodes is a map from node index to NodeID.
	Nodes []NodeID

	// Adj stores nodes and neighbors in an adjacency list.
	Adj [][]int
}

SimpleGraph stores a simplifed adj graph of a channel graph to speed up graph processing by eliminating all unnecessary hashing and map access.

func NewSimpleGraph 

func NewSimpleGraph(g ChannelGraph) (*SimpleGraph, error)

NewSimpleGraph creates a simplified graph from the current channel graph. Returns an error if the channel graph iteration fails due to underlying failure.

type TopCentrality 

type TopCentrality struct {
	// contains filtered or unexported fields
}

TopCentrality is a simple greedy technique to create connections to nodes with the top betweenness centrality value. This algorithm is usually referred to as TopK in the literature. The idea is that by opening channels to nodes with top betweenness centrality we also increase our own betweenness centrality (given we already have at least one channel, or create at least two new channels). A different and much better approach is instead of selecting nodes with top centrality value, we extend the graph in a loop by inserting a new non existing edge and recalculate the betweenness centrality of each node. This technique is usually referred to as "greedy" algorithm and gives better results than TopK but is considerably slower too.

func NewTopCentrality 

func NewTopCentrality() *TopCentrality

NewTopCentrality constructs and returns a new TopCentrality heuristic.

func (*TopCentrality) Name 

func (g *TopCentrality) Name() string

Name returns the name of the heuristic.

func (*TopCentrality) NodeScores 

func (g *TopCentrality) NodeScores(graph ChannelGraph, chans []Channel,
	chanSize ltcutil.Amount, nodes map[NodeID]struct{}) (
	map[NodeID]*NodeScore, error)

NodeScores will return a [0,1] normalized map of scores for the given nodes except for the ones we already have channels with. The scores will simply be the betweenness centrality values of the nodes. As our current implementation of betweenness centrality is non-incremental, NodeScores will recalculate the centrality values on every call, which is slow for large graphs.

type WeightedCombAttachment 

type WeightedCombAttachment struct {
	// contains filtered or unexported fields
}

WeightedCombAttachment is an implementation of the AttachmentHeuristic interface that combines the scores given by several sub-heuristics into one.

func NewWeightedCombAttachment 

func NewWeightedCombAttachment(h ...*WeightedHeuristic) (
	*WeightedCombAttachment, error)

NewWeightedCombAttachment creates a new instance of a WeightedCombAttachment.

func (*WeightedCombAttachment) Name 

func (c *WeightedCombAttachment) Name() string

Name returns the name of this heuristic.

NOTE: This is a part of the AttachmentHeuristic interface.

func (*WeightedCombAttachment) NodeScores 

func (c *WeightedCombAttachment) NodeScores(g ChannelGraph, chans []Channel,
	chanSize ltcutil.Amount, nodes map[NodeID]struct{}) (
	map[NodeID]*NodeScore, error)

NodeScores is a method that given the current channel graph, current set of local channels and funds available, scores the given nodes according to the preference of opening a channel with them. The returned channel candidates maps the NodeID to an attachment directive containing a score and a channel size.

The scores is determined by quering the set of sub-heuristics, then combining these scores into a final score according to the active configuration.

The returned scores will be in the range [0, 1.0], where 0 indicates no improvement in connectivity if a channel is opened to this node, while 1.0 is the maximum possible improvement in connectivity.

NOTE: This is a part of the AttachmentHeuristic interface.

func (*WeightedCombAttachment) SetNodeScores 

func (c *WeightedCombAttachment) SetNodeScores(targetHeuristic string,
	newScores map[NodeID]float64) (bool, error)

SetNodeScores is used to set the internal map from NodeIDs to scores. The passed scores must be in the range [0, 1.0]. The fist parameter is the name of the targeted heuristic, to allow recursively target specific sub-heuristics. The returned boolean indicates whether the targeted heuristic was found.

Since this heuristic doesn't keep any internal scores, it will recursively apply the scores to its sub-heuristics.

NOTE: This is a part of the ScoreSettable interface.

type WeightedHeuristic 

type WeightedHeuristic struct {
	// Weight is this AttachmentHeuristic's relative weight factor. It
	// should be between 0.0 and 1.0.
	Weight float64

	AttachmentHeuristic
}

WeightedHeuristic is a tuple that associates a weight to an AttachmentHeuristic. This is used to determining a node's final score when querying several heuristics for scores.

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