package rand
Import Path
math/rand (on golang.org and go.dev)
Dependency Relation
imports 2 packages, and imported by 5 packages
Involved Source Files
exp.go
normal.go
Package rand implements pseudo-random number generators.
Random numbers are generated by a Source. Top-level functions, such as
Float64 and Int, use a default shared Source that produces a deterministic
sequence of values each time a program is run. Use the Seed function to
initialize the default Source if different behavior is required for each run.
The default Source is safe for concurrent use by multiple goroutines, but
Sources created by NewSource are not.
Mathematical interval notation such as [0, n) is used throughout the
documentation for this package.
For random numbers suitable for security-sensitive work, see the crypto/rand
package.
rng.go
zipf.go
Package-Level Type Names (total 4)
A Rand is a source of random numbers.
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
Float32 returns, as a float32, a pseudo-random number in [0.0,1.0).
Float64 returns, as a float64, a pseudo-random number in [0.0,1.0).
Int returns a non-negative pseudo-random int.
Int31 returns a non-negative pseudo-random 31-bit integer as an int32.
Int31n returns, as an int32, a non-negative pseudo-random number in [0,n).
It panics if n <= 0.
Int63 returns a non-negative pseudo-random 63-bit integer as an int64.
Int63n returns, as an int64, a non-negative pseudo-random number in [0,n).
It panics if n <= 0.
Intn returns, as an int, a non-negative pseudo-random number in [0,n).
It panics if n <= 0.
NormFloat64 returns a normally distributed float64 in
the range -math.MaxFloat64 through +math.MaxFloat64 inclusive,
with standard normal distribution (mean = 0, stddev = 1).
To produce a different normal distribution, callers can
adjust the output using:
sample = NormFloat64() * desiredStdDev + desiredMean
Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n).
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.
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.
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.
Uint32 returns a pseudo-random 32-bit value as a uint32.
Uint64 returns a pseudo-random 64-bit value as a uint64.
*T : Source
*T : Source64
*T : io.Reader
func New(src Source) *Rand
func NewZipf(r *Rand, s float64, v float64, imax uint64) *Zipf
func math/big.(*Int).Rand(rnd *Rand, n *big.Int) *big.Int
func testing/quick.Value(t reflect.Type, rand *Rand) (value reflect.Value, ok bool)
func testing/quick.Generator.Generate(rand *Rand, size int) reflect.Value
A Source represents a source of uniformly-distributed
pseudo-random int64 values in the range [0, 1<<63).
( T) Int63() int64
( T) Seed(seed int64)
*Rand
Source64 (interface)
func NewSource(seed int64) Source
func New(src Source) *Rand
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.
( T) Int63() int64
( T) Seed(seed int64)
( T) Uint64() uint64
*Rand
T : Source
Package-Level Functions (total 19)
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
Float32 returns, as a float32, a pseudo-random number in [0.0,1.0)
from the default Source.
Float64 returns, as a float64, a pseudo-random number in [0.0,1.0)
from the default Source.
Int returns a non-negative pseudo-random int from the default Source.
Int31 returns a non-negative pseudo-random 31-bit integer as an int32
from the default Source.
Int31n returns, as an int32, a non-negative pseudo-random number in [0,n)
from the default Source.
It panics if n <= 0.
Int63 returns a non-negative pseudo-random 63-bit integer as an int64
from the default Source.
Int63n returns, as an int64, a non-negative pseudo-random number in [0,n)
from the default Source.
It panics if n <= 0.
Intn returns, as an int, a non-negative pseudo-random number in [0,n)
from the default Source.
It panics if n <= 0.
New returns a new Rand that uses random values from src
to generate other random values.
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.
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.
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
Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n)
from the default Source.
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.
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 2³¹-1 generate the same pseudo-random sequence.
Seed, unlike the Rand.Seed method, is safe for concurrent use.
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.
Uint32 returns a pseudo-random 32-bit value as a uint32
from the default Source.
Uint64 returns a pseudo-random 64-bit value as a uint64
from the default Source.
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