Imported Upstream version 1.4upstream/1.4

1 files changed, 0 insertions, 75 deletions

diff --git a/src/pkg/math/rand/zipf.go b/src/pkg/math/rand/zipf.go
deleted file mode 100644
index 8db2c6f5b..000000000
--- a/src/pkg/math/rand/zipf.go
+++ /dev/null
@@ -1,75 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// W.Hormann, G.Derflinger:
-// "Rejection-Inversion to Generate Variates
-// from Monotone Discrete Distributions"
-// http://eeyore.wu-wien.ac.at/papers/96-04-04.wh-der.ps.gz
-
-package rand
-
-import "math"
-
-// A Zipf generates Zipf distributed variates.
-type Zipf struct {
-	r            *Rand
-	imax         float64
-	v            float64
-	q            float64
-	s            float64
-	oneminusQ    float64
-	oneminusQinv float64
-	hxm          float64
-	hx0minusHxm  float64
-}
-
-func (z *Zipf) h(x float64) float64 {
-	return math.Exp(z.oneminusQ*math.Log(z.v+x)) * z.oneminusQinv
-}
-
-func (z *Zipf) hinv(x float64) float64 {
-	return math.Exp(z.oneminusQinv*math.Log(z.oneminusQ*x)) - z.v
-}
-
-// NewZipf returns a Zipf generating variates p(k) on [0, imax]
-// proportional to (v+k)**(-s) where s>1 and k>=0, and v>=1.
-func NewZipf(r *Rand, s float64, v float64, imax uint64) *Zipf {
-	z := new(Zipf)
-	if s <= 1.0 || v < 1 {
-		return nil
-	}
-	z.r = r
-	z.imax = float64(imax)
-	z.v = v
-	z.q = s
-	z.oneminusQ = 1.0 - z.q
-	z.oneminusQinv = 1.0 / z.oneminusQ
-	z.hxm = z.h(z.imax + 0.5)
-	z.hx0minusHxm = z.h(0.5) - math.Exp(math.Log(z.v)*(-z.q)) - z.hxm
-	z.s = 1 - z.hinv(z.h(1.5)-math.Exp(-z.q*math.Log(z.v+1.0)))
-	return z
-}
-
-// Uint64 returns a value drawn from the Zipf distribution described
-// by the Zipf object.
-func (z *Zipf) Uint64() uint64 {
-	if z == nil {
-		panic("rand: nil Zipf")
-	}
-	k := 0.0
-
-	for {
-		r := z.r.Float64() // r on [0,1]
-		ur := z.hxm + r*z.hx0minusHxm
-		x := z.hinv(ur)
-		k = math.Floor(x + 0.5)
-		if k-x <= z.s {
-			break
-		}
-		if ur >= z.h(k+0.5)-math.Exp(-math.Log(k+z.v)*z.q) {
-			break
-		}
-	}
-	return uint64(k)
-}