diff --git a/vendor/github.com/hashicorp/serf/coordinate/client.go b/vendor/github.com/hashicorp/serf/coordinate/client.go
new file mode 100644
index 0000000..3582ee4
--- /dev/null
+++ b/vendor/github.com/hashicorp/serf/coordinate/client.go
@@ -0,0 +1,243 @@
+package coordinate
+
+import (
+	"fmt"
+	"math"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/armon/go-metrics"
+)
+
+// Client manages the estimated network coordinate for a given node, and adjusts
+// it as the node observes round trip times and estimated coordinates from other
+// nodes. The core algorithm is based on Vivaldi, see the documentation for Config
+// for more details.
+type Client struct {
+	// coord is the current estimate of the client's network coordinate.
+	coord *Coordinate
+
+	// origin is a coordinate sitting at the origin.
+	origin *Coordinate
+
+	// config contains the tuning parameters that govern the performance of
+	// the algorithm.
+	config *Config
+
+	// adjustmentIndex is the current index into the adjustmentSamples slice.
+	adjustmentIndex uint
+
+	// adjustment is used to store samples for the adjustment calculation.
+	adjustmentSamples []float64
+
+	// latencyFilterSamples is used to store the last several RTT samples,
+	// keyed by node name. We will use the config's LatencyFilterSamples
+	// value to determine how many samples we keep, per node.
+	latencyFilterSamples map[string][]float64
+
+	// stats is used to record events that occur when updating coordinates.
+	stats ClientStats
+
+	// mutex enables safe concurrent access to the client.
+	mutex sync.RWMutex
+}
+
+// ClientStats is used to record events that occur when updating coordinates.
+type ClientStats struct {
+	// Resets is incremented any time we reset our local coordinate because
+	// our calculations have resulted in an invalid state.
+	Resets int
+}
+
+// NewClient creates a new Client and verifies the configuration is valid.
+func NewClient(config *Config) (*Client, error) {
+	if !(config.Dimensionality > 0) {
+		return nil, fmt.Errorf("dimensionality must be >0")
+	}
+
+	return &Client{
+		coord:                NewCoordinate(config),
+		origin:               NewCoordinate(config),
+		config:               config,
+		adjustmentIndex:      0,
+		adjustmentSamples:    make([]float64, config.AdjustmentWindowSize),
+		latencyFilterSamples: make(map[string][]float64),
+	}, nil
+}
+
+// GetCoordinate returns a copy of the coordinate for this client.
+func (c *Client) GetCoordinate() *Coordinate {
+	c.mutex.RLock()
+	defer c.mutex.RUnlock()
+
+	return c.coord.Clone()
+}
+
+// SetCoordinate forces the client's coordinate to a known state.
+func (c *Client) SetCoordinate(coord *Coordinate) error {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	if err := c.checkCoordinate(coord); err != nil {
+		return err
+	}
+
+	c.coord = coord.Clone()
+	return nil
+}
+
+// ForgetNode removes any client state for the given node.
+func (c *Client) ForgetNode(node string) {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	delete(c.latencyFilterSamples, node)
+}
+
+// Stats returns a copy of stats for the client.
+func (c *Client) Stats() ClientStats {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	return c.stats
+}
+
+// checkCoordinate returns an error if the coordinate isn't compatible with
+// this client, or if the coordinate itself isn't valid. This assumes the mutex
+// has been locked already.
+func (c *Client) checkCoordinate(coord *Coordinate) error {
+	if !c.coord.IsCompatibleWith(coord) {
+		return fmt.Errorf("dimensions aren't compatible")
+	}
+
+	if !coord.IsValid() {
+		return fmt.Errorf("coordinate is invalid")
+	}
+
+	return nil
+}
+
+// latencyFilter applies a simple moving median filter with a new sample for
+// a node. This assumes that the mutex has been locked already.
+func (c *Client) latencyFilter(node string, rttSeconds float64) float64 {
+	samples, ok := c.latencyFilterSamples[node]
+	if !ok {
+		samples = make([]float64, 0, c.config.LatencyFilterSize)
+	}
+
+	// Add the new sample and trim the list, if needed.
+	samples = append(samples, rttSeconds)
+	if len(samples) > int(c.config.LatencyFilterSize) {
+		samples = samples[1:]
+	}
+	c.latencyFilterSamples[node] = samples
+
+	// Sort a copy of the samples and return the median.
+	sorted := make([]float64, len(samples))
+	copy(sorted, samples)
+	sort.Float64s(sorted)
+	return sorted[len(sorted)/2]
+}
+
+// updateVivialdi updates the Vivaldi portion of the client's coordinate. This
+// assumes that the mutex has been locked already.
+func (c *Client) updateVivaldi(other *Coordinate, rttSeconds float64) {
+	const zeroThreshold = 1.0e-6
+
+	dist := c.coord.DistanceTo(other).Seconds()
+	if rttSeconds < zeroThreshold {
+		rttSeconds = zeroThreshold
+	}
+	wrongness := math.Abs(dist-rttSeconds) / rttSeconds
+
+	totalError := c.coord.Error + other.Error
+	if totalError < zeroThreshold {
+		totalError = zeroThreshold
+	}
+	weight := c.coord.Error / totalError
+
+	c.coord.Error = c.config.VivaldiCE*weight*wrongness + c.coord.Error*(1.0-c.config.VivaldiCE*weight)
+	if c.coord.Error > c.config.VivaldiErrorMax {
+		c.coord.Error = c.config.VivaldiErrorMax
+	}
+
+	delta := c.config.VivaldiCC * weight
+	force := delta * (rttSeconds - dist)
+	c.coord = c.coord.ApplyForce(c.config, force, other)
+}
+
+// updateAdjustment updates the adjustment portion of the client's coordinate, if
+// the feature is enabled. This assumes that the mutex has been locked already.
+func (c *Client) updateAdjustment(other *Coordinate, rttSeconds float64) {
+	if c.config.AdjustmentWindowSize == 0 {
+		return
+	}
+
+	// Note that the existing adjustment factors don't figure in to this
+	// calculation so we use the raw distance here.
+	dist := c.coord.rawDistanceTo(other)
+	c.adjustmentSamples[c.adjustmentIndex] = rttSeconds - dist
+	c.adjustmentIndex = (c.adjustmentIndex + 1) % c.config.AdjustmentWindowSize
+
+	sum := 0.0
+	for _, sample := range c.adjustmentSamples {
+		sum += sample
+	}
+	c.coord.Adjustment = sum / (2.0 * float64(c.config.AdjustmentWindowSize))
+}
+
+// updateGravity applies a small amount of gravity to pull coordinates towards
+// the center of the coordinate system to combat drift. This assumes that the
+// mutex is locked already.
+func (c *Client) updateGravity() {
+	dist := c.origin.DistanceTo(c.coord).Seconds()
+	force := -1.0 * math.Pow(dist/c.config.GravityRho, 2.0)
+	c.coord = c.coord.ApplyForce(c.config, force, c.origin)
+}
+
+// Update takes other, a coordinate for another node, and rtt, a round trip
+// time observation for a ping to that node, and updates the estimated position of
+// the client's coordinate. Returns the updated coordinate.
+func (c *Client) Update(node string, other *Coordinate, rtt time.Duration) (*Coordinate, error) {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	if err := c.checkCoordinate(other); err != nil {
+		return nil, err
+	}
+
+	// The code down below can handle zero RTTs, which we have seen in
+	// https://github.com/hashicorp/consul/issues/3789, presumably in
+	// environments with coarse-grained monotonic clocks (we are still
+	// trying to pin this down). In any event, this is ok from a code PoV
+	// so we don't need to alert operators with spammy messages. We did
+	// add a counter so this is still observable, though.
+	const maxRTT = 10 * time.Second
+	if rtt < 0 || rtt > maxRTT {
+		return nil, fmt.Errorf("round trip time not in valid range, duration %v is not a positive value less than %v ", rtt, maxRTT)
+	}
+	if rtt == 0 {
+		metrics.IncrCounter([]string{"serf", "coordinate", "zero-rtt"}, 1)
+	}
+
+	rttSeconds := c.latencyFilter(node, rtt.Seconds())
+	c.updateVivaldi(other, rttSeconds)
+	c.updateAdjustment(other, rttSeconds)
+	c.updateGravity()
+	if !c.coord.IsValid() {
+		c.stats.Resets++
+		c.coord = NewCoordinate(c.config)
+	}
+
+	return c.coord.Clone(), nil
+}
+
+// DistanceTo returns the estimated RTT from the client's coordinate to other, the
+// coordinate for another node.
+func (c *Client) DistanceTo(other *Coordinate) time.Duration {
+	c.mutex.RLock()
+	defer c.mutex.RUnlock()
+
+	return c.coord.DistanceTo(other)
+}
diff --git a/vendor/github.com/hashicorp/serf/coordinate/config.go b/vendor/github.com/hashicorp/serf/coordinate/config.go
new file mode 100644
index 0000000..b85a8ab
--- /dev/null
+++ b/vendor/github.com/hashicorp/serf/coordinate/config.go
@@ -0,0 +1,70 @@
+package coordinate
+
+// Config is used to set the parameters of the Vivaldi-based coordinate mapping
+// algorithm.
+//
+// The following references are called out at various points in the documentation
+// here:
+//
+// [1] Dabek, Frank, et al. "Vivaldi: A decentralized network coordinate system."
+//     ACM SIGCOMM Computer Communication Review. Vol. 34. No. 4. ACM, 2004.
+// [2] Ledlie, Jonathan, Paul Gardner, and Margo I. Seltzer. "Network Coordinates
+//     in the Wild." NSDI. Vol. 7. 2007.
+// [3] Lee, Sanghwan, et al. "On suitability of Euclidean embedding for
+//     host-based network coordinate systems." Networking, IEEE/ACM Transactions
+//     on 18.1 (2010): 27-40.
+type Config struct {
+	// The dimensionality of the coordinate system. As discussed in [2], more
+	// dimensions improves the accuracy of the estimates up to a point. Per [2]
+	// we chose 8 dimensions plus a non-Euclidean height.
+	Dimensionality uint
+
+	// VivaldiErrorMax is the default error value when a node hasn't yet made
+	// any observations. It also serves as an upper limit on the error value in
+	// case observations cause the error value to increase without bound.
+	VivaldiErrorMax float64
+
+	// VivaldiCE is a tuning factor that controls the maximum impact an
+	// observation can have on a node's confidence. See [1] for more details.
+	VivaldiCE float64
+
+	// VivaldiCC is a tuning factor that controls the maximum impact an
+	// observation can have on a node's coordinate. See [1] for more details.
+	VivaldiCC float64
+
+	// AdjustmentWindowSize is a tuning factor that determines how many samples
+	// we retain to calculate the adjustment factor as discussed in [3]. Setting
+	// this to zero disables this feature.
+	AdjustmentWindowSize uint
+
+	// HeightMin is the minimum value of the height parameter. Since this
+	// always must be positive, it will introduce a small amount error, so
+	// the chosen value should be relatively small compared to "normal"
+	// coordinates.
+	HeightMin float64
+
+	// LatencyFilterSamples is the maximum number of samples that are retained
+	// per node, in order to compute a median. The intent is to ride out blips
+	// but still keep the delay low, since our time to probe any given node is
+	// pretty infrequent. See [2] for more details.
+	LatencyFilterSize uint
+
+	// GravityRho is a tuning factor that sets how much gravity has an effect
+	// to try to re-center coordinates. See [2] for more details.
+	GravityRho float64
+}
+
+// DefaultConfig returns a Config that has some default values suitable for
+// basic testing of the algorithm, but not tuned to any particular type of cluster.
+func DefaultConfig() *Config {
+	return &Config{
+		Dimensionality:       8,
+		VivaldiErrorMax:      1.5,
+		VivaldiCE:            0.25,
+		VivaldiCC:            0.25,
+		AdjustmentWindowSize: 20,
+		HeightMin:            10.0e-6,
+		LatencyFilterSize:    3,
+		GravityRho:           150.0,
+	}
+}
diff --git a/vendor/github.com/hashicorp/serf/coordinate/coordinate.go b/vendor/github.com/hashicorp/serf/coordinate/coordinate.go
new file mode 100644
index 0000000..fbe792c
--- /dev/null
+++ b/vendor/github.com/hashicorp/serf/coordinate/coordinate.go
@@ -0,0 +1,203 @@
+package coordinate
+
+import (
+	"math"
+	"math/rand"
+	"time"
+)
+
+// Coordinate is a specialized structure for holding network coordinates for the
+// Vivaldi-based coordinate mapping algorithm. All of the fields should be public
+// to enable this to be serialized. All values in here are in units of seconds.
+type Coordinate struct {
+	// Vec is the Euclidean portion of the coordinate. This is used along
+	// with the other fields to provide an overall distance estimate. The
+	// units here are seconds.
+	Vec []float64
+
+	// Err reflects the confidence in the given coordinate and is updated
+	// dynamically by the Vivaldi Client. This is dimensionless.
+	Error float64
+
+	// Adjustment is a distance offset computed based on a calculation over
+	// observations from all other nodes over a fixed window and is updated
+	// dynamically by the Vivaldi Client. The units here are seconds.
+	Adjustment float64
+
+	// Height is a distance offset that accounts for non-Euclidean effects
+	// which model the access links from nodes to the core Internet. The access
+	// links are usually set by bandwidth and congestion, and the core links
+	// usually follow distance based on geography.
+	Height float64
+}
+
+const (
+	// secondsToNanoseconds is used to convert float seconds to nanoseconds.
+	secondsToNanoseconds = 1.0e9
+
+	// zeroThreshold is used to decide if two coordinates are on top of each
+	// other.
+	zeroThreshold = 1.0e-6
+)
+
+// ErrDimensionalityConflict will be panic-d if you try to perform operations
+// with incompatible dimensions.
+type DimensionalityConflictError struct{}
+
+// Adds the error interface.
+func (e DimensionalityConflictError) Error() string {
+	return "coordinate dimensionality does not match"
+}
+
+// NewCoordinate creates a new coordinate at the origin, using the given config
+// to supply key initial values.
+func NewCoordinate(config *Config) *Coordinate {
+	return &Coordinate{
+		Vec:        make([]float64, config.Dimensionality),
+		Error:      config.VivaldiErrorMax,
+		Adjustment: 0.0,
+		Height:     config.HeightMin,
+	}
+}
+
+// Clone creates an independent copy of this coordinate.
+func (c *Coordinate) Clone() *Coordinate {
+	vec := make([]float64, len(c.Vec))
+	copy(vec, c.Vec)
+	return &Coordinate{
+		Vec:        vec,
+		Error:      c.Error,
+		Adjustment: c.Adjustment,
+		Height:     c.Height,
+	}
+}
+
+// componentIsValid returns false if a floating point value is a NaN or an
+// infinity.
+func componentIsValid(f float64) bool {
+	return !math.IsInf(f, 0) && !math.IsNaN(f)
+}
+
+// IsValid returns false if any component of a coordinate isn't valid, per the
+// componentIsValid() helper above.
+func (c *Coordinate) IsValid() bool {
+	for i := range c.Vec {
+		if !componentIsValid(c.Vec[i]) {
+			return false
+		}
+	}
+
+	return componentIsValid(c.Error) &&
+		componentIsValid(c.Adjustment) &&
+		componentIsValid(c.Height)
+}
+
+// IsCompatibleWith checks to see if the two coordinates are compatible
+// dimensionally. If this returns true then you are guaranteed to not get
+// any runtime errors operating on them.
+func (c *Coordinate) IsCompatibleWith(other *Coordinate) bool {
+	return len(c.Vec) == len(other.Vec)
+}
+
+// ApplyForce returns the result of applying the force from the direction of the
+// other coordinate.
+func (c *Coordinate) ApplyForce(config *Config, force float64, other *Coordinate) *Coordinate {
+	if !c.IsCompatibleWith(other) {
+		panic(DimensionalityConflictError{})
+	}
+
+	ret := c.Clone()
+	unit, mag := unitVectorAt(c.Vec, other.Vec)
+	ret.Vec = add(ret.Vec, mul(unit, force))
+	if mag > zeroThreshold {
+		ret.Height = (ret.Height+other.Height)*force/mag + ret.Height
+		ret.Height = math.Max(ret.Height, config.HeightMin)
+	}
+	return ret
+}
+
+// DistanceTo returns the distance between this coordinate and the other
+// coordinate, including adjustments.
+func (c *Coordinate) DistanceTo(other *Coordinate) time.Duration {
+	if !c.IsCompatibleWith(other) {
+		panic(DimensionalityConflictError{})
+	}
+
+	dist := c.rawDistanceTo(other)
+	adjustedDist := dist + c.Adjustment + other.Adjustment
+	if adjustedDist > 0.0 {
+		dist = adjustedDist
+	}
+	return time.Duration(dist * secondsToNanoseconds)
+}
+
+// rawDistanceTo returns the Vivaldi distance between this coordinate and the
+// other coordinate in seconds, not including adjustments. This assumes the
+// dimensions have already been checked to be compatible.
+func (c *Coordinate) rawDistanceTo(other *Coordinate) float64 {
+	return magnitude(diff(c.Vec, other.Vec)) + c.Height + other.Height
+}
+
+// add returns the sum of vec1 and vec2. This assumes the dimensions have
+// already been checked to be compatible.
+func add(vec1 []float64, vec2 []float64) []float64 {
+	ret := make([]float64, len(vec1))
+	for i := range ret {
+		ret[i] = vec1[i] + vec2[i]
+	}
+	return ret
+}
+
+// diff returns the difference between the vec1 and vec2. This assumes the
+// dimensions have already been checked to be compatible.
+func diff(vec1 []float64, vec2 []float64) []float64 {
+	ret := make([]float64, len(vec1))
+	for i := range ret {
+		ret[i] = vec1[i] - vec2[i]
+	}
+	return ret
+}
+
+// mul returns vec multiplied by a scalar factor.
+func mul(vec []float64, factor float64) []float64 {
+	ret := make([]float64, len(vec))
+	for i := range vec {
+		ret[i] = vec[i] * factor
+	}
+	return ret
+}
+
+// magnitude computes the magnitude of the vec.
+func magnitude(vec []float64) float64 {
+	sum := 0.0
+	for i := range vec {
+		sum += vec[i] * vec[i]
+	}
+	return math.Sqrt(sum)
+}
+
+// unitVectorAt returns a unit vector pointing at vec1 from vec2. If the two
+// positions are the same then a random unit vector is returned. We also return
+// the distance between the points for use in the later height calculation.
+func unitVectorAt(vec1 []float64, vec2 []float64) ([]float64, float64) {
+	ret := diff(vec1, vec2)
+
+	// If the coordinates aren't on top of each other we can normalize.
+	if mag := magnitude(ret); mag > zeroThreshold {
+		return mul(ret, 1.0/mag), mag
+	}
+
+	// Otherwise, just return a random unit vector.
+	for i := range ret {
+		ret[i] = rand.Float64() - 0.5
+	}
+	if mag := magnitude(ret); mag > zeroThreshold {
+		return mul(ret, 1.0/mag), 0.0
+	}
+
+	// And finally just give up and make a unit vector along the first
+	// dimension. This should be exceedingly rare.
+	ret = make([]float64, len(ret))
+	ret[0] = 1.0
+	return ret, 0.0
+}
diff --git a/vendor/github.com/hashicorp/serf/coordinate/phantom.go b/vendor/github.com/hashicorp/serf/coordinate/phantom.go
new file mode 100644
index 0000000..6fb033c
--- /dev/null
+++ b/vendor/github.com/hashicorp/serf/coordinate/phantom.go
@@ -0,0 +1,187 @@
+package coordinate
+
+import (
+	"fmt"
+	"math"
+	"math/rand"
+	"time"
+)
+
+// GenerateClients returns a slice with nodes number of clients, all with the
+// given config.
+func GenerateClients(nodes int, config *Config) ([]*Client, error) {
+	clients := make([]*Client, nodes)
+	for i, _ := range clients {
+		client, err := NewClient(config)
+		if err != nil {
+			return nil, err
+		}
+
+		clients[i] = client
+	}
+	return clients, nil
+}
+
+// GenerateLine returns a truth matrix as if all the nodes are in a straight linke
+// with the given spacing between them.
+func GenerateLine(nodes int, spacing time.Duration) [][]time.Duration {
+	truth := make([][]time.Duration, nodes)
+	for i := range truth {
+		truth[i] = make([]time.Duration, nodes)
+	}
+
+	for i := 0; i < nodes; i++ {
+		for j := i + 1; j < nodes; j++ {
+			rtt := time.Duration(j-i) * spacing
+			truth[i][j], truth[j][i] = rtt, rtt
+		}
+	}
+	return truth
+}
+
+// GenerateGrid returns a truth matrix as if all the nodes are in a two dimensional
+// grid with the given spacing between them.
+func GenerateGrid(nodes int, spacing time.Duration) [][]time.Duration {
+	truth := make([][]time.Duration, nodes)
+	for i := range truth {
+		truth[i] = make([]time.Duration, nodes)
+	}
+
+	n := int(math.Sqrt(float64(nodes)))
+	for i := 0; i < nodes; i++ {
+		for j := i + 1; j < nodes; j++ {
+			x1, y1 := float64(i%n), float64(i/n)
+			x2, y2 := float64(j%n), float64(j/n)
+			dx, dy := x2-x1, y2-y1
+			dist := math.Sqrt(dx*dx + dy*dy)
+			rtt := time.Duration(dist * float64(spacing))
+			truth[i][j], truth[j][i] = rtt, rtt
+		}
+	}
+	return truth
+}
+
+// GenerateSplit returns a truth matrix as if half the nodes are close together in
+// one location and half the nodes are close together in another. The lan factor
+// is used to separate the nodes locally and the wan factor represents the split
+// between the two sides.
+func GenerateSplit(nodes int, lan time.Duration, wan time.Duration) [][]time.Duration {
+	truth := make([][]time.Duration, nodes)
+	for i := range truth {
+		truth[i] = make([]time.Duration, nodes)
+	}
+
+	split := nodes / 2
+	for i := 0; i < nodes; i++ {
+		for j := i + 1; j < nodes; j++ {
+			rtt := lan
+			if (i <= split && j > split) || (i > split && j <= split) {
+				rtt += wan
+			}
+			truth[i][j], truth[j][i] = rtt, rtt
+		}
+	}
+	return truth
+}
+
+// GenerateCircle returns a truth matrix for a set of nodes, evenly distributed
+// around a circle with the given radius. The first node is at the "center" of the
+// circle because it's equidistant from all the other nodes, but we place it at
+// double the radius, so it should show up above all the other nodes in height.
+func GenerateCircle(nodes int, radius time.Duration) [][]time.Duration {
+	truth := make([][]time.Duration, nodes)
+	for i := range truth {
+		truth[i] = make([]time.Duration, nodes)
+	}
+
+	for i := 0; i < nodes; i++ {
+		for j := i + 1; j < nodes; j++ {
+			var rtt time.Duration
+			if i == 0 {
+				rtt = 2 * radius
+			} else {
+				t1 := 2.0 * math.Pi * float64(i) / float64(nodes)
+				x1, y1 := math.Cos(t1), math.Sin(t1)
+				t2 := 2.0 * math.Pi * float64(j) / float64(nodes)
+				x2, y2 := math.Cos(t2), math.Sin(t2)
+				dx, dy := x2-x1, y2-y1
+				dist := math.Sqrt(dx*dx + dy*dy)
+				rtt = time.Duration(dist * float64(radius))
+			}
+			truth[i][j], truth[j][i] = rtt, rtt
+		}
+	}
+	return truth
+}
+
+// GenerateRandom returns a truth matrix for a set of nodes with normally
+// distributed delays, with the given mean and deviation. The RNG is re-seeded
+// so you always get the same matrix for a given size.
+func GenerateRandom(nodes int, mean time.Duration, deviation time.Duration) [][]time.Duration {
+	rand.Seed(1)
+
+	truth := make([][]time.Duration, nodes)
+	for i := range truth {
+		truth[i] = make([]time.Duration, nodes)
+	}
+
+	for i := 0; i < nodes; i++ {
+		for j := i + 1; j < nodes; j++ {
+			rttSeconds := rand.NormFloat64()*deviation.Seconds() + mean.Seconds()
+			rtt := time.Duration(rttSeconds * secondsToNanoseconds)
+			truth[i][j], truth[j][i] = rtt, rtt
+		}
+	}
+	return truth
+}
+
+// Simulate runs the given number of cycles using the given list of clients and
+// truth matrix. On each cycle, each client will pick a random node and observe
+// the truth RTT, updating its coordinate estimate. The RNG is re-seeded for
+// each simulation run to get deterministic results (for this algorithm and the
+// underlying algorithm which will use random numbers for position vectors when
+// starting out with everything at the origin).
+func Simulate(clients []*Client, truth [][]time.Duration, cycles int) {
+	rand.Seed(1)
+
+	nodes := len(clients)
+	for cycle := 0; cycle < cycles; cycle++ {
+		for i, _ := range clients {
+			if j := rand.Intn(nodes); j != i {
+				c := clients[j].GetCoordinate()
+				rtt := truth[i][j]
+				node := fmt.Sprintf("node_%d", j)
+				clients[i].Update(node, c, rtt)
+			}
+		}
+	}
+}
+
+// Stats is returned from the Evaluate function with a summary of the algorithm
+// performance.
+type Stats struct {
+	ErrorMax float64
+	ErrorAvg float64
+}
+
+// Evaluate uses the coordinates of the given clients to calculate estimated
+// distances and compares them with the given truth matrix, returning summary
+// stats.
+func Evaluate(clients []*Client, truth [][]time.Duration) (stats Stats) {
+	nodes := len(clients)
+	count := 0
+	for i := 0; i < nodes; i++ {
+		for j := i + 1; j < nodes; j++ {
+			est := clients[i].DistanceTo(clients[j].GetCoordinate()).Seconds()
+			actual := truth[i][j].Seconds()
+			error := math.Abs(est-actual) / actual
+			stats.ErrorMax = math.Max(stats.ErrorMax, error)
+			stats.ErrorAvg += error
+			count += 1
+		}
+	}
+
+	stats.ErrorAvg /= float64(count)
+	fmt.Printf("Error avg=%9.6f max=%9.6f\n", stats.ErrorAvg, stats.ErrorMax)
+	return
+}