Simplify the code
diff --git a/stat/running/running.go b/stat/running/running.go
index 342dd5b..58ef3e3 100644
--- a/stat/running/running.go
+++ b/stat/running/running.go
@@ -8,44 +8,41 @@
// Mean is a running mean accumulator.
type Mean struct {
- // Decay sets the decay rate. A value of 0.99 means that the effective count
- // is multiplied by 0.99 for every added value. If Decay is zero, a default
- // value of 1 is used (the count is not decayed).
- Decay float64
- // InitCount sets the initial count before accumulating.
- InitCount float64
- // InitMean sets the initial value for the mean before accumulating.
- // Note that InitMean has no effect if the InitCount is zero.
- InitMean float64
-
- set bool
+ decay float64
count float64
mean float64
}
-// Reset resets the counter. The next accumulate will use the
-// initial mean and count.
-func (m *Mean) Reset() {
- m.count = m.InitMean
- m.mean = m.InitCount
- m.set = true
+// NewMean returns a new accumulator for computing the running mean,
+// with the internal mean and count initialized to zero.
+// decay sets the decay rate for the internal sample counter. The count
+// is multiplied by the decay value for each sample added.
+func NewMean(decay float64) *Mean {
+ return &Mean{decay: decay}
+}
+
+// NewMeanInitialized returns a new Mean accumulator with initialized
+// values. decay sets the decay rate for the internal sample counter. The count
+// is multiplied by the decay value for each sample added. mean and count
+// specify the initial values for internal running mean and running count
+// respectively.
+func NewMeanInitialized(decay, mean, count float64) *Mean {
+ return &Mean{
+ decay: decay,
+ mean: mean,
+ count: count,
+ }
}
// Mean returns the current estimate of the running mean.
// Note that if the count is zero this returns the value
// of the initial mean.
func (m *Mean) Mean() float64 {
- if !m.set {
- m.Reset()
- }
return m.mean
}
// Count returns the current count of values.
func (m *Mean) Count() float64 {
- if !m.set {
- m.Reset()
- }
return m.count
}
@@ -60,23 +57,13 @@
if weight < 0 {
panic("running: negative weight")
}
- if !m.set {
- m.Reset()
- }
if m.count == 0 && weight == 0 {
// Avoid NaN.
return
}
- decay := m.decay()
+ decay := m.decay
decay = math.Pow(decay, weight)
m.count *= decay
m.mean = (m.mean*m.count + v*weight) / (m.count + weight)
m.count += weight
}
-
-func (m *Mean) decay() float64 {
- if m.Decay == 0 {
- return 1
- }
- return m.Decay
-}
