randvar

package
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Published: Jun 15, 2022 License: BSD-3-Clause Imports: 10 Imported by: 0

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Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func NewRand

func NewRand() *rand.Rand

NewRand creates a new random number generator seeded with the current time.

Types

type BytesFlag

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

BytesFlag provides a command line flag interface for specifying random bytes. The specification provides for both the length of the random bytes and a target compression ratio.

func NewBytesFlag

func NewBytesFlag(spec string) *BytesFlag

NewBytesFlag creates a new BytesFlag initialized with the specified spec.

func (*BytesFlag) Bytes

func (f *BytesFlag) Bytes(r *rand.Rand, buf []byte) []byte

Bytes returns random bytes. The length of the random bytes comes from the internal sizeFlag.

func (*BytesFlag) Set

func (f *BytesFlag) Set(spec string) error

Set implements the Flag.Value interface.

func (*BytesFlag) String

func (f *BytesFlag) String() string

func (*BytesFlag) Type

func (f *BytesFlag) Type() string

Type implements the Flag.Value interface.

type Deck

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

Deck is a random number generator that generates numbers in the range [0,len(weights)-1] where the probability of i is weights(i)/sum(weights). Unlike Weighted, the weights are specified as integers and used in a deck-of-cards style random number selection which ensures that each element is returned with a desired frequency within the size of the deck.

func NewDeck

func NewDeck(rng *rand.Rand, weights ...int) *Deck

NewDeck returns a new deck random number generator.

func (*Deck) Int

func (d *Deck) Int() int

Int returns a random number in the range [0,len(weights)-1] where the probability of i is weights(i)/sum(weights).

type Dynamic

type Dynamic interface {
	Static

	// Increment the max value the variable will return.
	IncMax(delta int)

	// Read the current max value the variable will return.
	Max() uint64
}

Dynamic models a random variable that pulls from a distribution with an upper bound that can change dynamically using the IncMax method.

type Flag

type Flag struct {
	Static
	// contains filtered or unexported fields
}

Flag provides a command line flag interface for specifying static random variables.

func NewFlag

func NewFlag(spec string) *Flag

NewFlag creates a new Flag initialized with the specified spec.

func (*Flag) Set

func (f *Flag) Set(spec string) error

Set implements the Flag.Value interface.

func (*Flag) String

func (f *Flag) String() string

func (*Flag) Type

func (f *Flag) Type() string

Type implements the Flag.Value interface.

type SkewedLatest

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

SkewedLatest is a random number generator that generates numbers in the range [min, max], but skews it towards max using a zipfian distribution.

func NewDefaultSkewedLatest

func NewDefaultSkewedLatest() (*SkewedLatest, error)

NewDefaultSkewedLatest constructs a new SkewedLatest generator with the default parameters.

func NewSkewedLatest

func NewSkewedLatest(min, max uint64, theta float64) (*SkewedLatest, error)

NewSkewedLatest constructs a new SkewedLatest generator with the given parameters. It returns an error if the parameters are outside the accepted range.

func (*SkewedLatest) IncMax

func (z *SkewedLatest) IncMax(delta int)

IncMax increments max.

func (*SkewedLatest) Max

func (z *SkewedLatest) Max() uint64

Max returns max.

func (*SkewedLatest) Uint64

func (z *SkewedLatest) Uint64(rng *rand.Rand) uint64

Uint64 returns a random Uint64 between min and max, where keys near max are most likely to be drawn.

type Static

type Static interface {
	Uint64(rng *rand.Rand) uint64
}

Static models a random variable that pulls from a distribution with static bounds

type Uniform

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

Uniform is a random number generator that generates draws from a uniform distribution.

func NewUniform

func NewUniform(min, max uint64) *Uniform

NewUniform constructs a new Uniform generator with the given parameters. Returns an error if the parameters are outside the accepted range.

func (*Uniform) IncMax

func (g *Uniform) IncMax(delta int)

IncMax increments max.

func (*Uniform) Max

func (g *Uniform) Max() uint64

Max returns the max value of the distribution.

func (*Uniform) Uint64

func (g *Uniform) Uint64(rng *rand.Rand) uint64

Uint64 returns a random Uint64 between min and max, drawn from a uniform distribution.

type Weighted

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

Weighted is a random number generator that generates numbers in the range [0,len(weights)-1] where the probability of i is weights(i)/sum(weights).

func NewWeighted

func NewWeighted(rng *rand.Rand, weights ...float64) *Weighted

NewWeighted returns a new weighted random number generator.

func (*Weighted) Int

func (w *Weighted) Int() int

Int returns a random number in the range [0,len(weights)-1] where the probability of i is weights(i)/sum(weights).

type Zipf

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

Zipf is a random number generator that generates random numbers from a Zipf distribution. Unlike rand.Zipf, this generator supports incrementing the max parameter without performing an expensive recomputation of the underlying hidden parameters, which is a pattern used in [1] for efficiently generating large volumes of Zipf-distributed records for synthetic data. Second, rand.Zipf only supports theta <= 1, we suppose all values of theta.

func NewDefaultZipf

func NewDefaultZipf() (*Zipf, error)

NewDefaultZipf constructs a new Zipf generator with the default parameters.

func NewZipf

func NewZipf(min, max uint64, theta float64) (*Zipf, error)

NewZipf constructs a new Zipf generator with the given parameters. Returns an error if the parameters are outside the accepted range.

func (*Zipf) IncMax

func (z *Zipf) IncMax(delta int)

IncMax increments max and recomputes the internal values that depend on it. Returns an error if the recomputation failed.

func (*Zipf) Max

func (z *Zipf) Max() uint64

Max returns the max.

func (*Zipf) Uint64

func (z *Zipf) Uint64(rng *rand.Rand) uint64

Uint64 draws a new value between min and max, with probabilities according to the Zipf distribution.

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