shit on stats

stats.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"math"
 )
 
 var _ = fmt.Print
@@ -9,12 +10,18 @@ var _ = fmt.Print
 const initialLength int = 1024
 const verySmall float64 = -100000
 const veryBig float64 = 100000
+const epsilon = 0.00000002
 
 type StatAggregator struct {
 	sum             float64
 	sumOfTheSquares float64
 	n               int
+	// histogram is a list of point between [min max] each point in the
+	//histogram represents the beginning of the histogram bars.
 	histogram            []float64
+	histogramValues      []int
+	histogramBarWidth    float64
+	numberOfHistogramBar int
 	min                  float64
 	max                  float64
 }
@@ -22,7 +29,15 @@ type StatAggregator struct {
 type Stats struct{}
 
 func NewStatAggregator() *StatAggregator {
-	return &StatAggregator{0, 0, 0, make([]float64, initialLength), veryBig, verySmall}
+	return &StatAggregator{0,
+		0,
+		0,
+		make([]float64, 0, initialLength),
+		make([]int, 0, initialLength),
+		0,
+		initialLength,
+		veryBig,
+		verySmall}
 }
 
 func (this *StatAggregator) AddStats(dataChannel chan float64, output chan *Stats) {
@@ -39,3 +54,37 @@ func (this *StatAggregator) AddStats(dataChannel chan float64, output chan *Stat
 	}
 	output <- nil
 }
+
+//  always assume the min and max includes the value!
+func (this *StatAggregator) AddDataToHistogram(value float64) {
+	if len(this.histogramValues) < this.numberOfHistogramBar {
+		this.AddDataToHistogramWhenLessDataThanBarAreOnHistograms(value)
+	} else {
+		this.AddDataToHistogramWithMaximalNumberOfBars(value)
+
+	}
+
+}
+
+func (this *StatAggregator) AddDataToHistogramWithMaximalNumberOfBars(value float64) {
+}
+
+func (this *StatAggregator) AddDataToHistogramWhenLessDataThanBarAreOnHistograms(value float64) {
+	for i, v := range this.histogram {
+		if math.Abs(value-v) < epsilon {
+			this.histogramValues[i]++
+			return
+		} else if value < v {
+			this.histogram = append(this.histogram, 0)
+			copy(this.histogram[i+1:], this.histogram[i:])
+			this.histogram[i] = value
+
+			this.histogramValues = append(this.histogramValues, 0)
+			copy(this.histogramValues[i+1:], this.histogramValues[i:])
+			this.histogramValues[i] = 1
+			return
+		}
+	}
+	this.histogramValues = append(this.histogramValues, 1)
+	this.histogram = append(this.histogram, value)
+}

stats_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"reflect"
 	"testing"
 )
 
@@ -9,9 +10,11 @@ func TestNewStats(t *testing.T) {
 	if s.n != 0 ||
 		s.sum != 0 ||
 		s.sumOfTheSquares != 0 ||
-		len(s.histogram) != initialLength ||
+		s.numberOfHistogramBar != initialLength ||
 		s.min != veryBig ||
-		s.max != verySmall {
+		s.max != verySmall ||
+		len(s.histogram) != 0 ||
+		len(s.histogramValues) != 0 {
 		t.Fail()
 	}
 }
@@ -31,5 +34,52 @@ func TestAddStatsBasic(t *testing.T) {
 	if s.n != 4. || s.min != -1. || s.max != 20. || s.sum != 23. || s.sumOfTheSquares != 411. {
 		t.Error(">>>", s.max, s.min)
 	}
+}
+
+func TestAddDataToHistogramWhenLessDataThanBarAreOnHistograms(t *testing.T) {
+	s := NewStatAggregator()
+	s.AddDataToHistogramWhenLessDataThanBarAreOnHistograms(17)
+	if !reflect.DeepEqual([]float64{17}, s.histogram) {
+		t.Error("bad histogram", s.histogram)
+	}
+	if !reflect.DeepEqual([]int{1}, s.histogramValues) {
+		t.Error("bad histogramValues:", s.histogramValues)
+	}
+	s.histogram = []float64{-1, 1, 2, 3}
+	s.histogramValues = []int{1, 1, 1, 1}
+	s.AddDataToHistogramWhenLessDataThanBarAreOnHistograms(2)
+	if !reflect.DeepEqual([]int{1, 1, 2, 1}, s.histogramValues) {
+		t.Error("bad histogramValues", s.histogramValues)
+	}
+
+	s.AddDataToHistogramWhenLessDataThanBarAreOnHistograms(2.5)
+	if !reflect.DeepEqual([]float64{-1, 1, 2, 2.5, 3}, s.histogram) {
+		t.Error("bad histogram", s.histogram)
+	}
+	if !reflect.DeepEqual([]int{1, 1, 2, 1, 1}, s.histogramValues) {
+		t.Error("bad histogramValues:", s.histogramValues)
+	}
+
+	s.AddDataToHistogramWhenLessDataThanBarAreOnHistograms(22.5)
+	if !reflect.DeepEqual([]float64{-1, 1, 2, 2.5, 3, 22.5}, s.histogram) {
+		t.Error("bad histogram", s.histogram)
+	}
+	if !reflect.DeepEqual([]int{1, 1, 2, 1, 1, 1}, s.histogramValues) {
+		t.Error("bad histogramValues:", s.histogramValues)
+	}
 
 }
+
+func TestAddDataToHistogramWithMaximalNumberOfBars(t *testing.T) {
+	s := NewStatAggregator()
+	s.numberOfHistogramBar = 5
+	s.histogram = []float64{1, 2, 3, 4, 5}
+	s.histogramValues = []int{1, 1, 2, 3, 4}
+	s.AddDataToHistogramWithMaximalNumberOfBars(3.5)
+	if !reflect.DeepEqual(s.histogram, []float64{1, 2, 3, 4, 5}) {
+		t.Fail()
+	}
+	if !reflect.DeepEqual(s.histogramValues, []int{1, 1, 2, 3, 4}) {
+		t.Fail()
+	}
+}