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) from the default Source. To produce a distribution with a different rate parameter, callers can adjust the output using:
sample = ExpFloat64() / desiredRateParameter
func Float32() float32
Float32 returns, as a float32, a pseudo-random number in [0.0,1.0) from the default Source.
func Float64() float64
Float64 returns, as a float64, a pseudo-random number in [0.0,1.0) from the default Source.
func Int() int
Int returns a non-negative pseudo-random int from the default Source.
func Int31() int32
Int31 returns a non-negative pseudo-random 31-bit integer as an int32 from the default Source.
func Int31n(n int32) int32
Int31n returns, as an int32, a non-negative pseudo-random number in [0,n) from the default Source. It panics if n <= 0.
func Int63() int64
Int63 returns a non-negative pseudo-random 63-bit integer as an int64 from the default Source.
func Int63n(n int64) int64
Int63n returns, as an int64, a non-negative pseudo-random number in [0,n) from the default Source. It panics if n <= 0.
func Intn(n int) int
Intn returns, as an int, a non-negative pseudo-random number in [0,n) from the default Source. It panics if n <= 0.
func NormFloat64() float64
NormFloat64 returns a normally distributed float64 in the range [-math.MaxFloat64, +math.MaxFloat64] with standard normal distribution (mean = 0, stddev = 1) from the default Source. To produce a different normal distribution, callers can adjust the output using:
sample = NormFloat64() * desiredStdDev + desiredMean
func Perm(n int) []int
Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n) from the default Source.
▹ Example
func Read(p []byte) (n int, err error)
Read generates len(p) random bytes from the default Source and writes them into p. It always returns len(p) and a nil error. Read, unlike the Rand.Read method, is safe for concurrent use.
func Seed(seed int64)
Seed uses the provided seed value to initialize the default Source to a deterministic state. If Seed is not called, the generator behaves as if seeded by Seed(1). Seed values that have the same remainder when divided by 2^31-1 generate the same pseudo-random sequence. Seed, unlike the Rand.Seed method, is safe for concurrent use.
func Shuffle(n int, swap func(i, j int))
Shuffle pseudo-randomizes the order of elements using the default Source. n is the number of elements. Shuffle panics if n < 0. swap swaps the elements with indexes i and j.
▹ Example
▹ Example (SlicesInUnison)
func Uint32() uint32
Uint32 returns a pseudo-random 32-bit value as a uint32 from the default Source.
func Uint64() uint64
Uint64 returns a pseudo-random 64-bit value as a uint64 from the default Source.
A Rand is a source of random numbers.
type Rand struct {
// contains filtered or unexported fields
}
func New(src Source) *Rand
New returns a new Rand that uses random values from src to generate other random values.
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 (r *Rand) Float32() float32
Float32 returns, as a float32, a pseudo-random number in [0.0,1.0).
func (r *Rand) Float64() float64
Float64 returns, as a float64, a pseudo-random number in [0.0,1.0).
func (r *Rand) Int() int
Int returns a non-negative pseudo-random int.
func (r *Rand) Int31() int32
Int31 returns a non-negative pseudo-random 31-bit integer as an int32.
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 (r *Rand) Int63() int64
Int63 returns a non-negative pseudo-random 63-bit integer as an int64.
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 (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 (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 (r *Rand) Perm(n int) []int
Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n).
func (r *Rand) Read(p []byte) (n int, err error)
Read generates len(p) random bytes and writes them into p. It always returns len(p) and a nil error. Read should not be called concurrently with any other Rand method.
func (r *Rand) Seed(seed int64)
Seed uses the provided seed value to initialize the generator to a deterministic state. Seed should not be called concurrently with any other Rand method.
func (r *Rand) Shuffle(n int, swap func(i, j int))
Shuffle pseudo-randomizes the order of elements. n is the number of elements. Shuffle panics if n < 0. swap swaps the elements with indexes i and j.
func (r *Rand) Uint32() uint32
Uint32 returns a pseudo-random 32-bit value as a uint32.
func (r *Rand) Uint64() uint64
Uint64 returns a pseudo-random 64-bit value as a uint64.
A Source represents a source of uniformly-distributed pseudo-random int64 values in the range [0, 1<<63).
type Source interface {
Int63() int64
Seed(seed int64)
}
func NewSource(seed int64) Source
NewSource returns a new pseudo-random Source seeded with the given value. Unlike the default Source used by top-level functions, this source is not safe for concurrent use by multiple goroutines.
A Source64 is a Source that can also generate uniformly-distributed pseudo-random uint64 values in the range [0, 1<<64) directly. If a Rand r's underlying Source s implements Source64, then r.Uint64 returns the result of one call to s.Uint64 instead of making two calls to s.Int63.
type Source64 interface {
Source
Uint64() uint64
}
A Zipf generates Zipf distributed variates.
type Zipf struct {
// contains filtered or unexported fields
}
func NewZipf(r *Rand, s float64, v float64, imax uint64) *Zipf
NewZipf returns a Zipf variate generator. The generator generates values k ∈ [0, imax] such that P(k) is proportional to (v + k) ** (-s). Requirements: s > 1 and v >= 1.
func (z *Zipf) Uint64() uint64
Uint64 returns a value drawn from the Zipf distribution described by the Zipf object.