feat(stats): add histogram, mean, meadian to numeric stat

using a default of 10 bins for histogram calculation

go.mod

@@ -66,5 +66,6 @@ require (
  go.starlark.net v0.0.0-20190528202925-30ae18b8564f
  golang.org/x/crypto v0.0.0-20190926180335-cea2066c6411
  golang.org/x/sys v0.0.0-20190926180325-855e68c8590b
+ gonum.org/v1/gonum v0.6.0
  gopkg.in/yaml.v2 v2.2.2
 )

go.sum

@@ -16,6 +16,7 @@ github.com/Stebalien/go-bitfield v0.0.0-20180330043415-076a62f9ce6e/go.mod h1:3o
 github.com/Stebalien/go-bitfield v0.0.1 h1:X3kbSSPUaJK60wV2hjOPZwmpljr6VGCqdq4cBLhbQBo=
 github.com/Stebalien/go-bitfield v0.0.1/go.mod h1:GNjFpasyUVkHMsfEOk8EFLJ9syQ6SI+XWrX9Wf2XH0s=
 github.com/aead/siphash v1.0.1/go.mod h1:Nywa3cDsYNNK3gaciGTWPwHt0wlpNV15vwmswBAUSII=
+github.com/ajstarks/svgo v0.0.0-20180226025133-644b8db467af/go.mod h1:K08gAheRH3/J6wwsYMMT4xOr94bZjxIelGM0+d/wbFw=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/andybalholm/cascadia v1.0.0 h1:hOCXnnZ5A+3eVDX8pvgl4kofXv2ELss0bKcqRySc45o=
@@ -89,6 +90,7 @@ github.com/facebookgo/atomicfile v0.0.0-20151019160806-2de1f203e7d5/go.mod h1:Jp
 github.com/fatih/color v1.7.0 h1:DkWD4oS2D8LGGgTQ6IvwJJXSL5Vp2ffcQg58nFV38Ys=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fd/go-nat v1.0.0/go.mod h1:BTBu/CKvMmOMUPkKVef1pngt2WFH/lg7E6yQnulfp6E=
+github.com/fogleman/gg v1.2.1-0.20190220221249-0403632d5b90/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/ghodss/yaml v1.0.0 h1:wQHKEahhL6wmXdzwWG11gIVCkOv05bNOh+Rxn0yngAk=
@@ -108,6 +110,7 @@ github.com/gogo/protobuf v1.2.1 h1:/s5zKNz0uPFCZ5hddgPdo2TK2TVrUNMn0OOX8/aZMTE=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
 github.com/gogo/protobuf v1.3.0 h1:G8O7TerXerS4F6sx9OV7/nRfJdnXgHZu/S/7F2SN+UE=
 github.com/gogo/protobuf v1.3.0/go.mod h1:SlYgWuQ5SjCEi6WLHjHCa1yvBfUnHcTbrrZtXPKa29o=
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6 h1:ZgQEtGgCBiWRM39fZuwSd1LwSqqSW0hOdXCYYDX0R3I=
 github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
@@ -336,6 +339,7 @@ github.com/jtolds/gls v4.2.1+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfVY
 github.com/jtolds/gls v4.20.0+incompatible h1:xdiiI2gbIgH/gLH7ADydsJ1uDOEzR8yvV7C0MuV77Wo=
 github.com/jtolds/gls v4.20.0+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfVYBRgL+9YlvaHOwJU=
 github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
+github.com/jung-kurt/gofpdf v1.0.3-0.20190309125859-24315acbbda5/go.mod h1:7Id9E/uU8ce6rXgefFLlgrJj/GYY22cpxn+r32jIOes=
 github.com/k0kubun/colorstring v0.0.0-20150214042306-9440f1994b88 h1:uC1QfSlInpQF+M0ao65imhwqKnz3Q2z/d8PWZRMQvDM=
 github.com/k0kubun/colorstring v0.0.0-20150214042306-9440f1994b88/go.mod h1:3w7q1U84EfirKl04SVQ/s7nPm1ZPhiXd34z40TNz36k=
 github.com/kami-zh/go-capturer v0.0.0-20171211120116-e492ea43421d/go.mod h1:P2viExyCEfeWGU259JnaQ34Inuec4R38JCyBx2edgD0=
@@ -873,7 +877,12 @@ golang.org/x/crypto v0.0.0-20190618222545-ea8f1a30c443/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20190923035154-9ee001bba392/go.mod h1:/lpIB1dKB+9EgE3H3cr1v9wB50oz8l4C4h62xy7jSTY=
 golang.org/x/crypto v0.0.0-20190926180335-cea2066c6411 h1:kuW9k4QvBJpRjC3rxEytsfIYPs8oGY3Jw7iR36h0FIY=
 golang.org/x/crypto v0.0.0-20190926180335-cea2066c6411/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/exp v0.0.0-20180321215751-8460e604b9de/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
+golang.org/x/exp v0.0.0-20180807140117-3d87b88a115f/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
+golang.org/x/exp v0.0.0-20190125153040-c74c464bbbf2 h1:y102fOLFqhV41b+4GPiJoa0k/x+pJcEi2/HB1Y5T6fU=
+golang.org/x/exp v0.0.0-20190125153040-c74c464bbbf2/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
+golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81/go.mod h1:ux5Hcp/YLpHSI86hEcLt0YII63i6oz57MZXIpbrjZUs=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
@@ -929,15 +938,22 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/tools v0.0.0-20180221164845-07fd8470d635/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20180525024113-a5b4c53f6e8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20181030221726-6c7e314b6563/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20181130052023-1c3d964395ce/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20190206041539-40960b6deb8e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20190328211700-ab21143f2384/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7 h1:9zdDQZ7Thm29KFXgAX/+yaf3eVbP7djjWp/dXAppNCc=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gonum.org/v1/gonum v0.0.0-20180816165407-929014505bf4/go.mod h1:Y+Yx5eoAFn32cQvJDxZx5Dpnq+c3wtXuadVZAcxbbBo=
+gonum.org/v1/gonum v0.6.0 h1:DJy6UzXbahnGUf1ujUNkh/NEtK14qMo2nvlBPs4U5yw=
+gonum.org/v1/gonum v0.6.0/go.mod h1:9mxDZsDKxgMAuccQkewq682L+0eCu4dCN2yonUJTCLU=
+gonum.org/v1/netlib v0.0.0-20190313105609-8cb42192e0e0/go.mod h1:wa6Ws7BG/ESfp6dHfk7C6KdzKA7wR7u/rKwOGE66zvw=
+gonum.org/v1/plot v0.0.0-20190515093506-e2840ee46a6b/go.mod h1:Wt8AAjI+ypCyYX3nZBvf6cAIx93T+c/OS2HFAYskSZc=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
@@ -962,3 +978,4 @@ gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+rsc.io/pdf v0.1.1/go.mod h1:n8OzWcQ6Sp37PL01nO98y4iUCRdTGarVfzxY20ICaU4=

lib/datasets_test.go

@@ -985,8 +985,8 @@ func TestDatasetRequestsStats(t *testing.T) {
  ref string
  expected []byte
  }{
- {"csv: me/cities", "me/cities", []byte(`[{"count":5,"maxLength":8,"minLength":7,"type":"string","unique":5},{"count":5,"max":40000000,"min":35000,"type":"numeric","unique":5},{"count":5,"frequencies":{"44.4":2},"max":65.25,"min":44.4,"type":"numeric","unique":3},{"count":5,"falseCount":1,"trueCount":4,"type":"boolean"}]`)},
- {"json: me/sitemap", "me/sitemap", []byte(`[{"count":10,"key":"contentLength","max":40079,"min":24515,"type":"numeric","unique":10},{"count":10,"frequencies":{"text/html; charset=utf-8":10},"key":"contentSniff","maxLength":24,"minLength":24,"type":"string"},{"count":10,"frequencies":{"text/html; charset=utf-8":10},"key":"contentType","maxLength":24,"minLength":24,"type":"string"},{"count":10,"key":"duration","max":4081577841,"min":74291866,"type":"numeric","unique":10},{"count":10,"key":"hash","maxLength":68,"minLength":68,"type":"string","unique":10},{"key":"links","type":"array","values":[{"count":10,"maxLength":58,"minLength":14,"unique":10},{"count":10,"maxLength":115,"minLength":19,"unique":10},{"count":10,"maxLength":68,"minLength":22,"unique":10},{"count":10,"maxLength":115,"minLength":14,"unique":10},{"count":9,"maxLength":70,"minLength":15,"unique":9},{"count":9,"maxLength":115,"minLength":37,"unique":9},{"count":9,"maxLength":52,"minLength":15,"unique":9},{"count":9,"maxLength":75,"minLength":19,"unique":9},{"count":9,"maxLength":66,"minLength":15,"unique":9},{"count":7,"maxLength":75,"minLength":19,"unique":7},{"count":7,"maxLength":66,"minLength":22,"unique":7},{"count":6,"maxLength":43,"minLength":19,"unique":6},{"count":6,"maxLength":77,"minLength":14,"unique":6},{"count":6,"maxLength":77,"minLength":21,"unique":6},{"count":4,"maxLength":43,"minLength":14,"unique":4},{"count":3,"maxLength":32,"minLength":21,"unique":3},{"count":3,"maxLength":42,"minLength":19,"unique":3},{"count":3,"maxLength":66,"minLength":32,"unique":3},{"count":3,"maxLength":46,"minLength":19,"unique":3},{"count":2,"maxLength":66,"minLength":22,"unique":2},{"count":2,"maxLength":32,"minLength":23,"unique":2},{"count":2,"maxLength":33,"minLength":22,"unique":2},{"count":2,"maxLength":32,"minLength":27,"unique":2},{"count":1,"maxLength":33,"minLength":33,"unique":1},{"count":1,"maxLength":27,"minLength":27,"unique":1}]},{"count":1,"key":"redirectTo","maxLength":18,"minLength":18,"type":"string","unique":1},{"count":11,"frequencies":{"200":10},"key":"status","max":301,"min":200,"type":"numeric","unique":1},{"count":11,"key":"timestamp","maxLength":35,"minLength":35,"type":"string","unique":11},{"count":10,"key":"title","maxLength":88,"minLength":53,"type":"string","unique":10},{"count":11,"key":"url","maxLength":78,"minLength":18,"type":"string","unique":11}]`)},
+ {"csv: me/cities", "me/cities", []byte(`[{"count":5,"maxLength":8,"minLength":7,"type":"string","unique":5},{"count":5,"histogram":{"bins":[35000,4031500.1,8028000.2,12024500.3,16021000.4,20017500.5,24014000.6,28010500.7,32007000.8,36003500.9,40000001],"frequencies":[3,0,1,0,0,0,0,0,0,1]},"max":40000000,"mean":9817000,"median":300000,"min":35000,"type":"numeric"},{"count":5,"histogram":{"bins":[44.4,46.585,48.769999999999996,50.955,53.14,55.325,57.51,59.695,61.879999999999995,64.065,66.25],"frequencies":[2,0,1,0,0,1,0,0,0,1]},"max":65.25,"mean":52.04,"median":44.4,"min":44.4,"type":"numeric"},{"count":5,"falseCount":1,"trueCount":4,"type":"boolean"}]`)},
+ {"json: me/sitemap", "me/sitemap", []byte(`[{"count":10,"histogram":{"bins":[24515,26071.5,27628,29184.5,30741,32297.5,33854,35410.5,36967,38523.5,40080],"frequencies":[4,0,3,1,0,0,1,0,0,1]},"key":"contentLength","max":40079,"mean":28825.8,"median":40079,"min":24515,"type":"numeric"},{"count":10,"frequencies":{"text/html; charset=utf-8":10},"key":"contentSniff","maxLength":24,"minLength":24,"type":"string"},{"count":10,"frequencies":{"text/html; charset=utf-8":10},"key":"contentType","maxLength":24,"minLength":24,"type":"string"},{"count":10,"histogram":{"bins":[74291866,475020463.6,875749061.2,1276477658.8000002,1677206256.4,2077934854,2478663451.6000004,2879392049.2000003,3280120646.8,3680849244.4,4081577842],"frequencies":[2,0,0,0,0,0,0,0,0,8]},"key":"duration","max":4081577841,"mean":3276899953.4,"median":89911449,"min":74291866,"type":"numeric"},{"count":10,"key":"hash","maxLength":68,"minLength":68,"type":"string","unique":10},{"key":"links","type":"array","values":[{"count":10,"maxLength":58,"minLength":14,"unique":10},{"count":10,"maxLength":115,"minLength":19,"unique":10},{"count":10,"maxLength":68,"minLength":22,"unique":10},{"count":10,"maxLength":115,"minLength":14,"unique":10},{"count":9,"maxLength":70,"minLength":15,"unique":9},{"count":9,"maxLength":115,"minLength":37,"unique":9},{"count":9,"maxLength":52,"minLength":15,"unique":9},{"count":9,"maxLength":75,"minLength":19,"unique":9},{"count":9,"maxLength":66,"minLength":15,"unique":9},{"count":7,"maxLength":75,"minLength":19,"unique":7},{"count":7,"maxLength":66,"minLength":22,"unique":7},{"count":6,"maxLength":43,"minLength":19,"unique":6},{"count":6,"maxLength":77,"minLength":14,"unique":6},{"count":6,"maxLength":77,"minLength":21,"unique":6},{"count":4,"maxLength":43,"minLength":14,"unique":4},{"count":3,"maxLength":32,"minLength":21,"unique":3},{"count":3,"maxLength":42,"minLength":19,"unique":3},{"count":3,"maxLength":66,"minLength":32,"unique":3},{"count":3,"maxLength":46,"minLength":19,"unique":3},{"count":2,"maxLength":66,"minLength":22,"unique":2},{"count":2,"maxLength":32,"minLength":23,"unique":2},{"count":2,"maxLength":33,"minLength":22,"unique":2},{"count":2,"maxLength":32,"minLength":27,"unique":2},{"count":1,"maxLength":33,"minLength":33,"unique":1},{"count":1,"maxLength":27,"minLength":27,"unique":1}]},{"count":1,"key":"redirectTo","maxLength":18,"minLength":18,"type":"string","unique":1},{"count":11,"histogram":{"bins":[200,210.2,220.4,230.6,240.8,251,261.2,271.4,281.6,291.8,302],"frequencies":[10,0,0,0,0,0,0,0,0,1]},"key":"status","max":301,"mean":209.1818181818182,"median":200,"min":200,"type":"numeric"},{"count":11,"key":"timestamp","maxLength":35,"minLength":35,"type":"string","unique":11},{"count":10,"key":"title","maxLength":88,"minLength":53,"type":"string","unique":10},{"count":11,"key":"url","maxLength":78,"minLength":18,"type":"string","unique":11}]`)},
  }
  for i, c := range goodCases {
  res := &StatsResponse{}

stats/stats.go

@@ -8,11 +8,12 @@ import (
  "fmt"
  "io"
  "sort"
- "strconv"
 
  logger "github.com/ipfs/go-log"
  "github.com/qri-io/dataset"
  "github.com/qri-io/dataset/dsio"
+ gonumfloats "gonum.org/v1/gonum/floats"
+ gonumstat "gonum.org/v1/gonum/stat"
 )
 
 var (
@@ -314,27 +315,34 @@ func (acc *arrayAcc) Close() {
  }
 }
 
-const maxUint = ^uint(0)
-const maxInt = int(maxUint >> 1)
-const minInt = -maxInt - 1
+const (
+ maxUint = ^uint(0)
+ maxFloat = float64(maxUint >> 1)
+ maxInt = int(maxUint >> 1)
+ minInt = -maxInt - 1
+)
 
 type numericAcc struct {
- typ string
- count int
- min float64
- max float64
- unique int
- frequencies map[float64]int
+ typ string
+ count int
+ min float64
+ max float64
+ mean float64
+ median float64
+ dividers []float64
+ histogram []float64
 }
 
 var _ accumulator = (*numericAcc)(nil)
 
 func newNumericAcc(typ string) *numericAcc {
  return &numericAcc{
- typ: typ,
- max: float64(minInt),
- min: float64(maxInt),
- frequencies: map[float64]int{},
+ typ: typ,
+ max: float64(minInt),
+ min: float64(maxInt),
+ median: maxFloat,
+ // use histogram to accumulate values
+ histogram: make([]float64, 0, StopFreqCountThreshold*100),
  }
 }
 
@@ -359,13 +367,14 @@ func (acc *numericAcc) Write(e dsio.Entry) {
  return
  }
 
- if acc.frequencies != nil {
- acc.frequencies[v]++
- if len(acc.frequencies) >= StopFreqCountThreshold {
- acc.frequencies = nil
+ if acc.histogram != nil {
+ acc.histogram = append(acc.histogram, v)
+ if len(acc.histogram) == StopFreqCountThreshold*100 {
+ acc.histogram = nil
  }
  }
 
+ acc.mean += v
  acc.count++
  if v > acc.max {
  acc.max = v
@@ -383,41 +392,43 @@ func (acc *numericAcc) Map() map[string]interface{} {
  return map[string]interface{}{"count": 0}
  }
  m := map[string]interface{}{
+ "mean": acc.mean,
  "count": acc.count,
  "min": acc.min,
  "max": acc.max,
  }
 
- if acc.unique != 0 {
- m["unique"] = acc.unique
+ if acc.median != maxFloat {
+ m["median"] = acc.median
  }
 
- if acc.frequencies != nil {
- // need to convert keys to strings b/c many serialization formats aren't
- // down with numeric map keys
- strFrq := map[string]int{}
- for fl, freq := range acc.frequencies {
- strFrq[strconv.FormatFloat(fl, 'f', -1, 64)] = freq
+ if acc.histogram != nil {
+ m["histogram"] = map[string][]float64{
+ "bins": acc.dividers,
+ "frequencies": acc.histogram,
  }
- m["frequencies"] = strFrq
  }
 
  return m
 }
 
 // Close finalizes the accumulator
 func (acc *numericAcc) Close() {
- if acc.frequencies != nil {
- // determine unique values
- for key, freq := range acc.frequencies {
- if freq == 1 {
- acc.unique++
- delete(acc.frequencies, key)
- }
- }
- if len(acc.frequencies) == 0 {
- acc.frequencies = nil
- }
+ // finalize avg
+ acc.mean = acc.mean / float64(acc.count)
+
+ if len(acc.histogram) > 0 {
+ acc.median = acc.histogram[len(acc.histogram)/2]
+
+ sort.Float64Slice(acc.histogram).Sort()
+ // turn values into a histogram
+ nBins := 10
+ acc.dividers = make([]float64, nBins+1)
+ // Increase the maximum divider so that the maximum value of x is contained
+ // within the last bucket.
+ gonumfloats.Span(acc.dividers, acc.min, acc.max+1)
+ // Span includes the min and the max. Trim the dividers to create 10 buckets
+ acc.histogram = gonumstat.Histogram(nil, acc.dividers, acc.histogram, nil)
  }
 }