add failtolerance also for probing

helper.go

@@ -0,0 +1,10 @@
+package main
+
+func absoluteDeltaPPM(base, amt int64) (deltaPPM int64) {
+
+	deltaPPM = (base - amt) * 1e6 / base
+	if deltaPPM < 0 {
+		return -deltaPPM
+	}
+	return deltaPPM
+}

main.go

@@ -47,7 +47,7 @@ type configParams struct {
 	Exclude             []string `long:"exclude" description:"don't use this node or your channel for routing (can be specified multiple times)" json:"exclude" toml:"exclude"`
 	To                  []string `long:"to" description:"try only this channel or node as target (should satisfy other constraints too; can be specified multiple times)" json:"to" toml:"to"`
 	From                []string `long:"from" description:"try only this channel or node as source (should satisfy other constraints too; can be specified multiple times)" json:"from" toml:"from"`
-	FailTolerance       int64    `long:"fail-tolerance" description:"if a channel failed before during this rebalance but chosen again by lnd, and the forward amount differs by less than this ppm, exclude the channel" json:"fail_tolerance" toml:"fail_tolerance"`
+	FailTolerance       int64    `long:"fail-tolerance" description:"a payment that differs from the prior attempt by this ppm will be cancelled" json:"fail_tolerance" toml:"fail_tolerance"`
 	AllowUnbalanceFrom  bool     `long:"allow-unbalance-from" description:"let the source channel go below 50% local liquidity, use if you want to drain a channel; you should also set --pfrom to >50" json:"allow_unbalance_from" toml:"allow_unbalance_from"`
 	AllowUnbalanceTo    bool     `long:"allow-unbalance-to" description:"let the target channel go above 50% local liquidity, use if you want to refill a channel; you should also set --pto to >50" json:"allow_unbalance_to" toml:"allow_unbalance_to"`
 	StatFilename        string   `short:"s" long:"stat" description:"save successful rebalance information to the specified CSV file" json:"stat" toml:"stat"`
@@ -374,6 +374,7 @@ func preflightChecks(params *configParams) error {
 	if params.FailTolerance == 0 {
 		params.FailTolerance = 1000
 	}
+
 	if (params.RelAmountFrom > 0 || params.RelAmountTo > 0) && params.AllowRapidRebalance {
 		return fmt.Errorf("use either relative amounts or rapid rebalance but not both")
 

mission_ctl.go

@@ -15,7 +15,7 @@ func (r *regolancer) validateRoute(route *lnrpc.Route) error {
 	prevHopPK := r.myPK
 	for _, h := range route.Hops {
 		hopPK := h.PubKey
-		if fp, ok := r.mcCache[prevHopPK+hopPK]; ok && 1e6-h.AmtToForwardMsat*1e6/fp < params.FailTolerance {
+		if fp, ok := r.mcCache[prevHopPK+hopPK]; ok && absoluteDeltaPPM(fp, h.AmtToForwardMsat) < params.FailTolerance {
 			from, err := hex.DecodeString(prevHopPK)
 			if err != nil {
 				return err

routes.go

@@ -195,7 +195,8 @@ func (r *regolancer) rebuildRoute(ctx context.Context, route *lnrpc.Route, amoun
 
 func (r *regolancer) probeRoute(ctx context.Context, route *lnrpc.Route,
 	goodAmount, badAmount, amount int64, steps int) (maxAmount int64, err error) {
-	if amount == badAmount || amount == goodAmount || amount == -goodAmount {
+	if absoluteDeltaPPM(badAmount, amount) <= params.FailTolerance || absoluteDeltaPPM(amount, goodAmount) <= params.FailTolerance || amount == -goodAmount {
+
 		bestAmount := hiWhiteColor(goodAmount)
 		if goodAmount <= 0 {
 			bestAmount = hiWhiteColor("unknown")