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author | Russ Cox <rsc@golang.org> | 2021-06-15 12:46:11 -0400 |
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committer | Russ Cox <rsc@golang.org> | 2021-06-16 16:38:43 +0000 |
commit | a294e4e798d75ee9cf167a75189b1b0dff3664f1 (patch) | |
tree | a58f1aee1323bc2f7a91f59082e4f8c08f13f8e1 /src/math | |
parent | a6a853f94cf00d8f581d0e6fbcc28898e39557b2 (diff) | |
download | go-a294e4e798d75ee9cf167a75189b1b0dff3664f1.tar.gz go-a294e4e798d75ee9cf167a75189b1b0dff3664f1.zip |
math/rand: mention half-open intervals explicitly
If someone sees "in [0,n)" it might look like a typo.
Saying "in the half-open interval [0,n)" will give people
something to search the web for (half-open interval).
Change-Id: I3c343f0a7171891e106e709ca77ab9db5daa5c84
Reviewed-on: https://go-review.googlesource.com/c/go/+/328210
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Diffstat (limited to 'src/math')
-rw-r--r-- | src/math/rand/rand.go | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/src/math/rand/rand.go b/src/math/rand/rand.go index 8179d9f464..13f20ca5ef 100644 --- a/src/math/rand/rand.go +++ b/src/math/rand/rand.go @@ -12,9 +12,6 @@ // 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. -// // This package's outputs might be easily predictable regardless of how it's // seeded. For random numbers suitable for security-sensitive work, see the // crypto/rand package. @@ -106,7 +103,7 @@ func (r *Rand) Int() int { return int(u << 1 >> 1) // clear sign bit if int == int32 } -// Int63n returns, as an int64, a non-negative pseudo-random number in [0,n). +// Int63n returns, as an int64, a non-negative pseudo-random number in the half-open interval [0,n). // It panics if n <= 0. func (r *Rand) Int63n(n int64) int64 { if n <= 0 { @@ -123,7 +120,7 @@ func (r *Rand) Int63n(n int64) int64 { return v % n } -// Int31n returns, as an int32, a non-negative pseudo-random number in [0,n). +// Int31n returns, as an int32, a non-negative pseudo-random number in the half-open interval [0,n). // It panics if n <= 0. func (r *Rand) Int31n(n int32) int32 { if n <= 0 { @@ -140,7 +137,7 @@ func (r *Rand) Int31n(n int32) int32 { return v % n } -// int31n returns, as an int32, a non-negative pseudo-random number in [0,n). +// int31n returns, as an int32, a non-negative pseudo-random number in the half-open interval [0,n). // n must be > 0, but int31n does not check this; the caller must ensure it. // int31n exists because Int31n is inefficient, but Go 1 compatibility // requires that the stream of values produced by math/rand remain unchanged. @@ -164,7 +161,7 @@ func (r *Rand) int31n(n int32) int32 { return int32(prod >> 32) } -// Intn returns, as an int, a non-negative pseudo-random number in [0,n). +// Intn returns, as an int, a non-negative pseudo-random number in the half-open interval [0,n). // It panics if n <= 0. func (r *Rand) Intn(n int) int { if n <= 0 { @@ -176,7 +173,7 @@ func (r *Rand) Intn(n int) int { return int(r.Int63n(int64(n))) } -// Float64 returns, as a float64, a pseudo-random number in [0.0,1.0). +// Float64 returns, as a float64, a pseudo-random number in the half-open interval [0.0,1.0). func (r *Rand) Float64() float64 { // A clearer, simpler implementation would be: // return float64(r.Int63n(1<<53)) / (1<<53) @@ -202,7 +199,7 @@ again: return f } -// Float32 returns, as a float32, a pseudo-random number in [0.0,1.0). +// Float32 returns, as a float32, a pseudo-random number in the half-open interval [0.0,1.0). func (r *Rand) Float32() float32 { // Same rationale as in Float64: we want to preserve the Go 1 value // stream except we want to fix it not to return 1.0 @@ -215,7 +212,8 @@ again: return f } -// Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n). +// Perm returns, as a slice of n ints, a pseudo-random permutation of the integers +// in the half-open interval [0,n). func (r *Rand) Perm(n int) []int { m := make([]int, n) // In the following loop, the iteration when i=0 always swaps m[0] with m[0]. @@ -323,31 +321,31 @@ func Int31() int32 { return globalRand.Int31() } // Int returns a non-negative pseudo-random int from the default Source. func Int() int { return globalRand.Int() } -// Int63n returns, as an int64, a non-negative pseudo-random number in [0,n) +// Int63n returns, as an int64, a non-negative pseudo-random number in the half-open interval [0,n) // from the default Source. // It panics if n <= 0. func Int63n(n int64) int64 { return globalRand.Int63n(n) } -// Int31n returns, as an int32, a non-negative pseudo-random number in [0,n) +// Int31n returns, as an int32, a non-negative pseudo-random number in the half-open interval [0,n) // from the default Source. // It panics if n <= 0. func Int31n(n int32) int32 { return globalRand.Int31n(n) } -// Intn returns, as an int, a non-negative pseudo-random number in [0,n) +// Intn returns, as an int, a non-negative pseudo-random number in the half-open interval [0,n) // from the default Source. // It panics if n <= 0. func Intn(n int) int { return globalRand.Intn(n) } -// Float64 returns, as a float64, a pseudo-random number in [0.0,1.0) +// Float64 returns, as a float64, a pseudo-random number in the half-open interval [0.0,1.0) // from the default Source. func Float64() float64 { return globalRand.Float64() } -// Float32 returns, as a float32, a pseudo-random number in [0.0,1.0) +// Float32 returns, as a float32, a pseudo-random number in the half-open interval [0.0,1.0) // from the default Source. func Float32() float32 { return globalRand.Float32() } -// Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n) -// from the default Source. +// Perm returns, as a slice of n ints, a pseudo-random permutation of the integers +// in the half-open interval [0,n) from the default Source. func Perm(n int) []int { return globalRand.Perm(n) } // Shuffle pseudo-randomizes the order of elements using the default Source. |