rand

Documentation

Overview

Package rand implements pseudo-random number generators.

Index

• func ExpFloat64() float64
• func Float32() float32
• func Float64() float64
• func Int() int
• func Int31() int32
• func Int31n(n int32) int32
• func Int63() int64
• func Int63n(n int64) int64
• func Intn(n int) int
• func NormFloat64() float64
• func Perm(n int) []int
• func Seed(seed int64)
• func Uint32() uint32
• type Rand
  • func New(src Source) *Rand
  • func (r *Rand) ExpFloat64() float64
  • func (r *Rand) Float32() float32
  • func (r *Rand) Float64() float64
  • func (r *Rand) Int() int
  • func (r *Rand) Int31() int32
  • func (r *Rand) Int31n(n int32) int32
  • func (r *Rand) Int63() int64
  • func (r *Rand) Int63n(n int64) int64
  • func (r *Rand) Intn(n int) int
  • func (r *Rand) NormFloat64() float64
  • func (r *Rand) Perm(n int) []int
  • func (r *Rand) Seed(seed int64)
  • func (r *Rand) Uint32() uint32
• type Source
  • func NewSource(seed int64) Source
• type Zipf
  • func NewZipf(r *Rand, s float64, v float64, imax uint64) *Zipf
  • func (z *Zipf) Uint64() uint64

Functions

func ExpFloat64

func ExpFloat64() float64

ExpFloat64 returns an exponentially distributed float64 in the range (0, +math.MaxFloat64] with an exponential distribution whose rate parameter (lambda) is 1 and whose mean is 1/lambda (1). To produce a distribution with a different rate parameter, callers can adjust the output using:

sample = ExpFloat64() / desiredRateParameter

func Float32

func Float32() float32

Float32 returns, as a float32, a pseudo-random number in [0.0,1.0).

func Float64

func Float64() float64

Float64 returns, as a float64, a pseudo-random number in [0.0,1.0).

func Int

func Int() int

Int returns a non-negative pseudo-random int.

func Int31

func Int31() int32

Int31 returns a non-negative pseudo-random 31-bit integer as an int32.

func Int31n

func Int31n(n int32) int32

Int31n returns, as an int32, a non-negative pseudo-random number in [0,n). It panics if n <= 0.

func Int63

func Int63() int64

Int63 returns a non-negative pseudo-random 63-bit integer as an int64.

func Int63n

func Int63n(n int64) int64

Int63n returns, as an int64, a non-negative pseudo-random number in [0,n). It panics if n <= 0.

func Intn

func Intn(n int) int

Intn returns, as an int, a non-negative pseudo-random number in [0,n). It panics if n <= 0.

func NormFloat64

func NormFloat64() float64

NormFloat64 returns a normally distributed float64 in the range [-math.MaxFloat64, +math.MaxFloat64] with standard normal distribution (mean = 0, stddev = 1). To produce a different normal distribution, callers can adjust the output using:

sample = NormFloat64() * desiredStdDev + desiredMean

func Perm

func Perm(n int) []int

Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n).

func Seed

func Seed(seed int64)

Seed uses the provided seed value to initialize the generator to a deterministic state. If Seed is not called, the generator behaves as if seeded by Seed(1).

func Uint32

func Uint32() uint32

Uint32 returns a pseudo-random 32-bit value as a uint32.

Types

type Rand

type Rand struct {
	// contains filtered or unexported fields
}

A Rand is a source of random numbers.

func New

func New(src Source) *Rand

New returns a new Rand that uses random values from src to generate other random values.

func (*Rand) ExpFloat64

func (r *Rand) ExpFloat64() float64

ExpFloat64 returns an exponentially distributed float64 in the range (0, +math.MaxFloat64] with an exponential distribution whose rate parameter (lambda) is 1 and whose mean is 1/lambda (1). To produce a distribution with a different rate parameter, callers can adjust the output using:

sample = ExpFloat64() / desiredRateParameter

func (*Rand) Float32

func (r *Rand) Float32() float32

Float32 returns, as a float32, a pseudo-random number in [0.0,1.0).

func (*Rand) Float64

func (r *Rand) Float64() float64

Float64 returns, as a float64, a pseudo-random number in [0.0,1.0).

func (*Rand) Int

func (r *Rand) Int() int

Int returns a non-negative pseudo-random int.

func (*Rand) Int31

func (r *Rand) Int31() int32

Int31 returns a non-negative pseudo-random 31-bit integer as an int32.

func (*Rand) Int31n

func (r *Rand) Int31n(n int32) int32

Int31n returns, as an int32, a non-negative pseudo-random number in [0,n). It panics if n <= 0.

func (*Rand) Int63

func (r *Rand) Int63() int64

Int63 returns a non-negative pseudo-random 63-bit integer as an int64.

func (*Rand) Int63n

func (r *Rand) Int63n(n int64) int64

Int63n returns, as an int64, a non-negative pseudo-random number in [0,n). It panics if n <= 0.

func (*Rand) Intn

func (r *Rand) Intn(n int) int

Intn returns, as an int, a non-negative pseudo-random number in [0,n). It panics if n <= 0.

func (*Rand) NormFloat64

func (r *Rand) NormFloat64() float64

NormFloat64 returns a normally distributed float64 in the range [-math.MaxFloat64, +math.MaxFloat64] with standard normal distribution (mean = 0, stddev = 1). To produce a different normal distribution, callers can adjust the output using:

sample = NormFloat64() * desiredStdDev + desiredMean

func (*Rand) Perm

func (r *Rand) Perm(n int) []int

Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n).

func (*Rand) Seed

func (r *Rand) Seed(seed int64)

Seed uses the provided seed value to initialize the generator to a deterministic state.

func (*Rand) Uint32

func (r *Rand) Uint32() uint32

Uint32 returns a pseudo-random 32-bit value as a uint32.

type Source

type Source interface {
	Int63() int64
	Seed(seed int64)
}

A Source represents a source of uniformly-distributed pseudo-random int64 values in the range [0, 1<<63).

func NewSource

func NewSource(seed int64) Source

NewSource returns a new pseudo-random Source seeded with the given value.

type Zipf

type Zipf struct {
	// contains filtered or unexported fields
}

A Zipf generates Zipf distributed variates.

func NewZipf

func NewZipf(r *Rand, s float64, v float64, imax uint64) *Zipf

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 (*Zipf) Uint64

func (z *Zipf) Uint64() uint64

Uint64 returns a value drawn from the Zipf distributed described by the Zipf object.