vieter-v
/
v
2
0
Fork 0
Code Issues Pull Requests Releases Activity

move util functions into main module

pull/13840/head
Subhomoy Haldar 2022-03-27 18:06:29 +05:30
parent 78832f9777
commit 9c6a961112
4 changed files with 118 additions and 150 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

117
vlib/rand/rand.v
View File

@ -274,6 +274,76 @@ pub fn (mut rng PRNG) ascii(len int) string {
return internal_string_from_set(mut rng, rand.ascii_chars, len)
}
// Configuration struct for the shuffle functions.
// The start index is inclusive and the end index is exclusive.
// Set the end to 0 to shuffle until the end of the array.
[params]
pub struct ShuffleConfigStruct {
pub:
start int
end int
}
fn (config ShuffleConfigStruct) validate_for<T>(a []T) ? {
if config.start < 0 || config.start >= a.len {
return error("argument 'config.start' must be in range [0, a.len)")
}
if config.end < 0 || config.end > a.len {
return error("argument 'config.end' must be in range [0, a.len]")
}
}
// shuffle randomly permutates the elements in `a`. The range for shuffling is
// optional and the entire array is shuffled by default. Leave the end as 0 to
// shuffle all elements until the end.
[direct_array_access]
pub fn (mut rng PRNG) shuffle<T>(mut a []T, config ShuffleConfigStruct) ? {
config.validate_for(a) ?
new_end := if config.end == 0 { a.len } else { config.end }
for i in config.start .. new_end {
x := rng.int_in_range(i, new_end) or { config.start }
// swap
a_i := a[i]
a[i] = a[x]
a[x] = a_i
}
}
// shuffle_clone returns a random permutation of the elements in `a`.
// The permutation is done on a fresh clone of `a`, so `a` remains unchanged.
pub fn (mut rng PRNG) shuffle_clone<T>(a []T, config ShuffleConfigStruct) ?[]T {
mut res := a.clone()
rng.shuffle(mut res, config) ?
return res
}
// choose samples k elements from the array without replacement.
// This means the indices cannot repeat and it restricts the sample size to be less than or equal to the size of the given array.
// Note that if the array has repeating elements, then the sample may have repeats as well.
pub fn (mut rng PRNG) choose<T>(array []T, k int) ?[]T {
n := array.len
if k > n {
return error('Cannot choose $k elements without replacement from a $n-element array.')
}
mut results := []T{len: k}
mut indices := []int{len: n, init: it}
rng.shuffle(mut indices) ?
for i in 0 .. k {
results[i] = array[indices[i]]
}
return results
}
// sample samples k elements from the array with replacement.
// This means the elements can repeat and the size of the sample may exceed the size of the array.
pub fn (mut rng PRNG) sample<T>(array []T, k int) []T {
mut results := []T{len: k}
for i in 0 .. k {
results[i] = array[rng.intn(array.len) or { 0 }]
}
return results
}
__global default_rng &PRNG
// new_default returns a new instance of the default RNG. If the seed is not provided, the current time will be used to seed the instance.
@ -468,45 +538,28 @@ pub fn ascii(len int) string {
return string_from_set(rand.ascii_chars, len)
}
// Configuration struct for the shuffle functions.
// The start index is inclusive and the end index is exclusive.
// Set the end to 0 to shuffle until the end of the array.
[params]
pub struct ShuffleConfigStruct {
pub:
start int
end int
}
fn (config ShuffleConfigStruct) validate_for<T>(a []T) ? {
if config.start < 0 || config.start >= a.len {
return error("argument 'config.start' must be in range [0, a.len)")
}
if config.end < 0 || config.end > a.len {
return error("argument 'config.end' must be in range [0, a.len]")
}
}
// shuffle randomly permutates the elements in `a`. The range for shuffling is
// optional and the entire array is shuffled by default. Leave the end as 0 to
// shuffle all elements until the end.
[direct_array_access]
pub fn shuffle<T>(mut a []T, config ShuffleConfigStruct) ? {
config.validate_for(a) ?
new_end := if config.end == 0 { a.len } else { config.end }
for i in config.start .. new_end {
x := int_in_range(i, new_end) or { config.start }
// swap
a_i := a[i]
a[i] = a[x]
a[x] = a_i
}
default_rng.shuffle(mut a, config) ?
}
// shuffle_clone returns a random permutation of the elements in `a`.
// The permutation is done on a fresh clone of `a`, so `a` remains unchanged.
pub fn shuffle_clone<T>(a []T, config ShuffleConfigStruct) ?[]T {
mut res := a.clone()
shuffle(mut res, config) ?
return res
return default_rng.shuffle_clone(a, config)
}
// choose samples k elements from the array without replacement.
// This means the indices cannot repeat and it restricts the sample size to be less than or equal to the size of the given array.
// Note that if the array has repeating elements, then the sample may have repeats as well.
pub fn choose<T>(array []T, k int) ?[]T {
return default_rng.choose(array, k)
}
// sample samples k elements from the array with replacement.
// This means the elements can repeat and the size of the sample may exceed the size of the array.
pub fn sample<T>(array []T, k int) []T {
return default_rng.sample(array, k)
}

42
vlib/rand/random_numbers_test.v
View File

@ -359,18 +359,12 @@ fn test_shuffle_partial() ? {
mut b := a.clone()
rand.shuffle(mut a, start: 4) ?
for i in 0 .. 4 {
assert a[i] == b[i]
}
assert a[..4] == b[..4]
a = b.clone()
rand.shuffle(mut a, start: 3, end: 7) ?
for i in 0 .. 3 {
assert a[i] == b[i]
}
for i in 7 .. a.len {
assert a[i] == b[i]
}
assert a[..3] == b[..3]
assert a[7..] == b[7..]
}
fn test_shuffle_clone() {
@ -387,3 +381,33 @@ fn test_shuffle_clone() {
assert results[idx] != original
}
}
fn test_choose() ? {
lengths := [1, 3, 4, 5, 6, 7]
a := ['one', 'two', 'three', 'four', 'five', 'six', 'seven']
for length in lengths {
b := rand.choose(a, length) ?
assert b.len == length
for element in b {
assert element in a
// make sure every element occurs once
mut count := 0
for e in b {
if e == element {
count++
}
}
assert count == 1
}
}
}
fn test_sample() {
k := 20
a := ['heads', 'tails']
b := rand.sample(a, k)
assert b.len == k
for element in b {
assert element in a
}
}

52
vlib/rand/util/util.v
View File

@ -1,52 +0,0 @@
// Copyright (c) 2019-2022 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module util
import rand
// sample_nr returns a sample of the array without replacement. This means the indices cannot repeat and it restricts the sample size to be less than or equal to the size of the given array. Note that if the array has repeating elements, then the sample may have repeats as well.
pub fn sample_nr<T>(array []T, k int) []T {
n := array.len
if k > n {
panic('Cannot sample $k elements without replacement from a $n-element array.')
}
mut results := []T{len: k}
mut indices := []int{len: n}
// Initialize with all indices
// temporary workaround for issue #10343
for i in 0 .. indices.len {
indices[i] = i
}
shuffle(mut indices, k)
for i in 0 .. k {
results[i] = array[indices[i]]
}
return results
}
// sample_r returns a sample of the array with replacement. This means the elements can repeat and the size of the sample may exceed the size of the array
pub fn sample_r<T>(array []T, k int) []T {
n := array.len
mut results := []T{len: k}
for i in 0 .. k {
results[i] = array[rand.intn(n) or { 0 }]
}
return results
}
// shuffle randomizes the first `n` items of an array in place (all if `n` is 0)
[direct_array_access]
pub fn shuffle<T>(mut a []T, n int) {
if n < 0 || n > a.len {
panic("argument 'n' must be in range [0, a.len]")
}
cnt := if n == 0 { a.len - 1 } else { n }
for i in 0 .. cnt {
x := rand.int_in_range(i, a.len) or { 0 }
// swap
a_i := a[i]
a[i] = a[x]
a[x] = a_i
}
}

57
vlib/rand/util/util_test.v
View File

@ -1,57 +0,0 @@
import rand
import rand.util
fn test_sample_nr() {
lengths := [1, 3, 4, 5, 6, 7]
a := ['one', 'two', 'three', 'four', 'five', 'six', 'seven']
for length in lengths {
b := util.sample_nr(a, length)
assert b.len == length
for element in b {
assert element in a
// make sure every element occurs once
mut count := 0
for e in b {
if e == element {
count++
}
}
assert count == 1
}
}
}
fn test_sample_r() {
k := 20
a := ['heads', 'tails']
b := util.sample_r(a, k)
assert b.len == k
for element in b {
assert element in a
}
}
fn test_shuffle() {
rand.seed([u32(1), 2]) // set seed to produce same results in order
a := [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
mut b := a.clone()
mut c := a.clone()
util.shuffle(mut b, 0)
util.shuffle(mut c, 0)
assert b == [6, 4, 5, 1, 9, 2, 10, 3, 8, 7]
assert c == [1, 6, 5, 8, 7, 2, 10, 9, 3, 4]
// test shuffling a slice
mut d := a.clone()
util.shuffle(mut d[..5], 0)
assert d == [5, 2, 1, 3, 4, 6, 7, 8, 9, 10]
assert d[5..] == a[5..]
// test shuffling n items
mut e := a.clone()
util.shuffle(mut e, 5)
assert e[..5] == [10, 3, 1, 8, 4]
assert e[5..] == [6, 7, 5, 9, 2]
// test shuffling empty array
mut f := a[..0]
util.shuffle(mut f, 0)
assert f == []int{}
}