routing: rename apriori estimator

* we rename the current probability estimator to be the "apriori"
  probability estimator to distinguish from a different implementation
  later
* the AprioriEstimator is exported to later be able to type switch
* getLocalPairProbability -> LocalPairProbabiltiy (later part of an
  exported interface)
* getPairProbability -> getPairProbabiltiy (later part of an exported
  interface)

lnrpc/routerrpc/router_server.go

@@ -472,7 +472,7 @@ func (s *Server) SetMissionControlConfig(ctx context.Context,
 	error) {
 
 	cfg := &routing.MissionControlConfig{
-		ProbabilityEstimatorCfg: routing.ProbabilityEstimatorCfg{
+		AprioriConfig: routing.AprioriConfig{
 			PenaltyHalfLife: time.Duration(
 				req.Config.HalfLifeSeconds,
 			) * time.Second,

routing/integrated_routing_context_test.go

@@ -75,7 +75,7 @@ func newIntegratedRoutingContext(t *testing.T) *integratedRoutingContext {
 		finalExpiry: 40,
 
 		mcCfg: MissionControlConfig{
-			ProbabilityEstimatorCfg: ProbabilityEstimatorCfg{
+			AprioriConfig: AprioriConfig{
 				PenaltyHalfLife:       30 * time.Minute,
 				AprioriHopProbability: 0.6,
 				AprioriWeight:         0.5,

routing/missioncontrol.go

@@ -103,7 +103,7 @@ type MissionControl struct {
 
 	// estimator is the probability estimator that is used with the payment
 	// results that mission control collects.
-	estimator *probabilityEstimator
+	estimator *AprioriEstimator
 
 	sync.Mutex
 
@@ -116,9 +116,8 @@ type MissionControl struct {
 // MissionControlConfig defines parameters that control mission control
 // behaviour.
 type MissionControlConfig struct {
-	// ProbabilityEstimatorConfig is the config we will use for probability
-	// calculations.
-	ProbabilityEstimatorCfg
+	// AprioriConfig is the config we will use for probability calculations.
+	AprioriConfig
 
 	// MaxMcHistory defines the maximum number of payment results that are
 	// held on disk.
@@ -135,7 +134,7 @@ type MissionControlConfig struct {
 }
 
 func (c *MissionControlConfig) validate() error {
-	if err := c.ProbabilityEstimatorCfg.validate(); err != nil {
+	if err := c.AprioriConfig.validate(); err != nil {
 		return err
 	}
 
@@ -225,8 +224,8 @@ func NewMissionControl(db kvdb.Backend, self route.Vertex,
 		return nil, err
 	}
 
-	estimator := &probabilityEstimator{
-		ProbabilityEstimatorCfg: cfg.ProbabilityEstimatorCfg,
+	estimator := &AprioriEstimator{
+		AprioriConfig:          cfg.AprioriConfig,
 		prevSuccessProbability: prevSuccessProbability,
 	}
 
@@ -284,7 +283,7 @@ func (m *MissionControl) GetConfig() *MissionControlConfig {
 	defer m.Unlock()
 
 	return &MissionControlConfig{
-		ProbabilityEstimatorCfg: m.estimator.ProbabilityEstimatorCfg,
+		AprioriConfig:           m.estimator.AprioriConfig,
 		MaxMcHistory:            m.store.maxRecords,
 		McFlushInterval:         m.store.flushInterval,
 		MinFailureRelaxInterval: m.state.minFailureRelaxInterval,
@@ -309,7 +308,7 @@ func (m *MissionControl) SetConfig(cfg *MissionControlConfig) error {
 
 	m.store.maxRecords = cfg.MaxMcHistory
 	m.state.minFailureRelaxInterval = cfg.MinFailureRelaxInterval
-	m.estimator.ProbabilityEstimatorCfg = cfg.ProbabilityEstimatorCfg
+	m.estimator.AprioriConfig = cfg.AprioriConfig
 
 	return nil
 }
@@ -344,10 +343,10 @@ func (m *MissionControl) GetProbability(fromNode, toNode route.Vertex,
 
 	// Use a distinct probability estimation function for local channels.
 	if fromNode == m.selfNode {
-		return m.estimator.getLocalPairProbability(now, results, toNode)
+		return m.estimator.LocalPairProbability(now, results, toNode)
 	}
 
-	return m.estimator.getPairProbability(
+	return m.estimator.PairProbability(
 		now, results, toNode, amt, capacity,
 	)
 }

routing/missioncontrol_test.go

@@ -93,7 +93,7 @@ func (ctx *mcTestContext) restartMc() {
 	mc, err := NewMissionControl(
 		ctx.db, mcTestSelf,
 		&MissionControlConfig{
-			ProbabilityEstimatorCfg: ProbabilityEstimatorCfg{
+			AprioriConfig: AprioriConfig{
 				PenaltyHalfLife:       testPenaltyHalfLife,
 				AprioriHopProbability: testAprioriHopProbability,
 				AprioriWeight:         testAprioriWeight,

routing/probability_apriori.go

@@ -53,15 +53,16 @@ var (
 
 	// ErrInvalidHopProbability is returned when we get an invalid hop
 	// probability.
-	ErrInvalidHopProbability = errors.New("hop probability must be in [0;1]")
+	ErrInvalidHopProbability = errors.New("hop probability must be in " +
+		"[0, 1]")
 
 	// ErrInvalidAprioriWeight is returned when we get an apriori weight
 	// that is out of range.
-	ErrInvalidAprioriWeight = errors.New("apriori weight must be in [0;1]")
+	ErrInvalidAprioriWeight = errors.New("apriori weight must be in [0, 1]")
 )
 
-// ProbabilityEstimatorCfg contains configuration for our probability estimator.
-type ProbabilityEstimatorCfg struct {
+// AprioriConfig contains configuration for our probability estimator.
+type AprioriConfig struct {
 	// PenaltyHalfLife defines after how much time a penalized node or
 	// channel is back at 50% probability.
 	PenaltyHalfLife time.Duration
@@ -80,7 +81,7 @@ type ProbabilityEstimatorCfg struct {
 	AprioriWeight float64
 }
 
-func (p ProbabilityEstimatorCfg) validate() error {
+func (p AprioriConfig) validate() error {
 	if p.PenaltyHalfLife < 0 {
 		return ErrInvalidHalflife
 	}
@@ -96,12 +97,11 @@ func (p ProbabilityEstimatorCfg) validate() error {
 	return nil
 }
 
-// probabilityEstimator returns node and pair probabilities based on historical
+// AprioriEstimator returns node and pair probabilities based on historical
 // payment results.
-type probabilityEstimator struct {
-	// ProbabilityEstimatorCfg contains configuration options for our
-	// estimator.
-	ProbabilityEstimatorCfg
+type AprioriEstimator struct {
+	// AprioriConfig contains configuration options for our estimator.
+	AprioriConfig
 
 	// prevSuccessProbability is the assumed probability for node pairs that
 	// successfully relayed the previous attempt.
@@ -111,7 +111,7 @@ type probabilityEstimator struct {
 // getNodeProbability calculates the probability for connections from a node
 // that have not been tried before. The results parameter is a list of last
 // payment results for that node.
-func (p *probabilityEstimator) getNodeProbability(now time.Time,
+func (p *AprioriEstimator) getNodeProbability(now time.Time,
 	results NodeResults, amt lnwire.MilliSatoshi,
 	capacity btcutil.Amount) float64 {
 
@@ -184,7 +184,7 @@ func (p *probabilityEstimator) getNodeProbability(now time.Time,
 // a payment result. Weight follows an exponential curve that starts at 1 when
 // the result is fresh and asymptotically approaches zero over time. The rate at
 // which this happens is controlled by the penaltyHalfLife parameter.
-func (p *probabilityEstimator) getWeight(age time.Duration) float64 {
+func (p *AprioriEstimator) getWeight(age time.Duration) float64 {
 	exp := -age.Hours() / p.PenaltyHalfLife.Hours()
 	return math.Pow(2, exp)
 }
@@ -219,12 +219,12 @@ func capacityFactor(amt lnwire.MilliSatoshi, capacity btcutil.Amount) float64 {
 	return 1 - 1/denominator
 }
 
-// getPairProbability estimates the probability of successfully traversing to
+// PairProbability estimates the probability of successfully traversing to
 // toNode based on historical payment outcomes for the from node. Those outcomes
 // are passed in via the results parameter.
-func (p *probabilityEstimator) getPairProbability(
-	now time.Time, results NodeResults, toNode route.Vertex,
-	amt lnwire.MilliSatoshi, capacity btcutil.Amount) float64 {
+func (p *AprioriEstimator) PairProbability(now time.Time,
+	results NodeResults, toNode route.Vertex, amt lnwire.MilliSatoshi,
+	capacity btcutil.Amount) float64 {
 
 	nodeProbability := p.getNodeProbability(now, results, amt, capacity)
 
@@ -233,9 +233,9 @@ func (p *probabilityEstimator) getPairProbability(
 	)
 }
 
-// getLocalPairProbability estimates the probability of successfully traversing
+// LocalPairProbability estimates the probability of successfully traversing
 // our own local channels to toNode.
-func (p *probabilityEstimator) getLocalPairProbability(
+func (p *AprioriEstimator) LocalPairProbability(
 	now time.Time, results NodeResults, toNode route.Vertex) float64 {
 
 	// For local channels that have never been tried before, we assume them
@@ -251,7 +251,7 @@ func (p *probabilityEstimator) getLocalPairProbability(
 
 // calculateProbability estimates the probability of successfully traversing to
 // toNode based on historical payment outcomes and a fall-back node probability.
-func (p *probabilityEstimator) calculateProbability(
+func (p *AprioriEstimator) calculateProbability(
 	now time.Time, results NodeResults,
 	nodeProbability float64, toNode route.Vertex,
 	amt lnwire.MilliSatoshi) float64 {

routing/probability_apriori_test.go

@@ -36,7 +36,7 @@ const (
 
 type estimatorTestContext struct {
 	t         *testing.T
-	estimator *probabilityEstimator
+	estimator *AprioriEstimator
 
 	// results contains a list of last results. Every element in the list
 	// corresponds to the last result towards a node. The list index equals
@@ -48,8 +48,8 @@ type estimatorTestContext struct {
 func newEstimatorTestContext(t *testing.T) *estimatorTestContext {
 	return &estimatorTestContext{
 		t: t,
-		estimator: &probabilityEstimator{
-			ProbabilityEstimatorCfg: ProbabilityEstimatorCfg{
+		estimator: &AprioriEstimator{
+			AprioriConfig: AprioriConfig{
 				AprioriHopProbability: aprioriHopProb,
 				AprioriWeight:         aprioriWeight,
 				PenaltyHalfLife:       time.Hour,
@@ -74,7 +74,7 @@ func (c *estimatorTestContext) assertPairProbability(now time.Time,
 
 	const tolerance = 0.01
 
-	p := c.estimator.getPairProbability(
+	p := c.estimator.PairProbability(
 		now, results, route.Vertex{toNode}, amt, capacity,
 	)
 	diff := p - expectedProb

routing/router_test.go

@@ -120,7 +120,7 @@ func createTestCtxFromGraphInstanceAssumeValid(t *testing.T,
 	}
 
 	mcConfig := &MissionControlConfig{
-		ProbabilityEstimatorCfg: ProbabilityEstimatorCfg{
+		AprioriConfig: AprioriConfig{
 			PenaltyHalfLife:       time.Hour,
 			AprioriHopProbability: 0.9,
 			AprioriWeight:         0.5,

server.go

@@ -868,7 +868,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 	// servers, the mission control instance itself can be moved there too.
 	routingConfig := routerrpc.GetRoutingConfig(cfg.SubRPCServers.RouterRPC)
 
-	estimatorCfg := routing.ProbabilityEstimatorCfg{
+	estimatorCfg := routing.AprioriConfig{
 		AprioriHopProbability: routingConfig.AprioriHopProbability,
 		PenaltyHalfLife:       routingConfig.PenaltyHalfLife,
 		AprioriWeight:         routingConfig.AprioriWeight,
@@ -877,7 +877,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 	s.missionControl, err = routing.NewMissionControl(
 		dbs.ChanStateDB, selfNode.PubKeyBytes,
 		&routing.MissionControlConfig{
-			ProbabilityEstimatorCfg: estimatorCfg,
+			AprioriConfig:           estimatorCfg,
 			MaxMcHistory:            routingConfig.MaxMcHistory,
 			McFlushInterval:         routingConfig.McFlushInterval,
 			MinFailureRelaxInterval: routing.DefaultMinFailureRelaxInterval,