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@@ -1,6 +1,10 @@
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+/*
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+Package core:math/rand implements various random number generators
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+*/
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package rand
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import "core:intrinsics"
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+import "core:mem"
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Rand :: struct {
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state: u64,
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@@ -12,17 +16,82 @@ Rand :: struct {
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@(private)
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global_rand := create(u64(intrinsics.read_cycle_counter()))
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+/*
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+Sets the seed used by the global random number generator.
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+
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+Inputs:
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+- seed: The seed value
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ set_global_seed_example :: proc() {
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+ rand.set_global_seed(1)
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+ fmt.println(rand.uint64())
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+ }
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+
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+Possible Output:
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+
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+ 10
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+
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+*/
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set_global_seed :: proc(seed: u64) {
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init(&global_rand, seed)
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}
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+/*
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+Creates a new random number generator.
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+
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+Inputs:
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+- seed: The seed value to create the random number generator with
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+
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+Returns:
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+- res: The created random number generator
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ create_example :: proc() {
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+ my_rand := rand.create(1)
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+ fmt.println(rand.uint64(&my_rand))
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+ }
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+
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+Possible Output:
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+
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+ 10
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+
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+*/
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@(require_results)
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-create :: proc(seed: u64) -> Rand {
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+create :: proc(seed: u64) -> (res: Rand) {
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r: Rand
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init(&r, seed)
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return r
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}
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+/*
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+Initialises a random number generator.
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+
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+Inputs:
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+- r: The random number generator to initialise
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+- seed: The seed value to initialise this random number generator
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ init_example :: proc() {
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+ my_rand: rand.Rand
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+ rand.init(&my_rand, 1)
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+ fmt.println(rand.uint64(&my_rand))
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+ }
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+
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+Possible Output:
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+
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+ 10
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+
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+*/
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init :: proc(r: ^Rand, seed: u64) {
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r.state = 0
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r.inc = (seed << 1) | 1
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@@ -31,6 +100,35 @@ init :: proc(r: ^Rand, seed: u64) {
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_random(r)
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}
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+/*
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+Initialises a random number generator to use the system random number generator.
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+The system random number generator is platform specific.
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+On `linux` refer to the `getrandom` syscall.
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+On `darwin` refer to `getentropy`.
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+On `windows` refer to `BCryptGenRandom`.
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+
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+All other platforms wi
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+
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+Inputs:
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+- r: The random number generator to use the system random number generator
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+
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+WARNING: Panics if the system is not either `windows`, `darwin` or `linux`
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ init_as_system_example :: proc() {
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+ my_rand: rand.Rand
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+ rand.init_as_system(&my_rand)
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+ fmt.println(rand.uint64(&my_rand))
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+ }
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+
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+Possible Output:
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+
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+ 10
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+
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+*/
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init_as_system :: proc(r: ^Rand) {
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if !#defined(_system_random) {
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panic(#procedure + " is not supported on this platform yet")
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@@ -61,18 +159,99 @@ _random :: proc(r: ^Rand) -> u32 {
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return (xor_shifted >> rot) | (xor_shifted << ((-rot) & 31))
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}
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+/*
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+Generates a random 32 bit value using the provided random number generator. If no generator is provided the global random number generator will be used.
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+
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+Inputs:
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+- r: The random number generator to use, or nil for the global generator
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+
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+Returns:
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+- val: A random unsigned 32 bit value
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ uint32_example :: proc() {
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+ // Using the global random number generator
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+ fmt.println(rand.uint32())
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+ // Using local random number generator
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+ my_rand := rand.create(1)
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+ fmt.println(rand.uint32(&my_rand))
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+ }
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+
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+Possible Output:
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+
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+ 10
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+ 389
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+
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+*/
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@(require_results)
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-uint32 :: proc(r: ^Rand = nil) -> u32 { return _random(r) }
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+uint32 :: proc(r: ^Rand = nil) -> (val: u32) { return _random(r) }
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+
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+/*
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+Generates a random 64 bit value using the provided random number generator. If no generator is provided the global random number generator will be used.
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+
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+Inputs:
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+- r: The random number generator to use, or nil for the global generator
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+
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+Returns:
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+- val: A random unsigned 64 bit value
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ uint64_example :: proc() {
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+ // Using the global random number generator
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+ fmt.println(rand.uint64())
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+ // Using local random number generator
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+ my_rand := rand.create(1)
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+ fmt.println(rand.uint64(&my_rand))
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+ }
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+
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+Possible Output:
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+ 10
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+ 389
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+
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+*/
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@(require_results)
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-uint64 :: proc(r: ^Rand = nil) -> u64 {
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+uint64 :: proc(r: ^Rand = nil) -> (val: u64) {
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a := u64(_random(r))
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b := u64(_random(r))
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return (a<<32) | b
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}
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+/*
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+Generates a random 128 bit value using the provided random number generator. If no generator is provided the global random number generator will be used.
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+
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+Inputs:
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+- r: The random number generator to use, or nil for the global generator
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+
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+Returns:
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+- val: A random unsigned 128 bit value
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ uint128_example :: proc() {
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+ // Using the global random number generator
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+ fmt.println(rand.uint128())
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+ // Using local random number generator
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+ my_rand := rand.create(1)
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+ fmt.println(rand.uint128(&my_rand))
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+ }
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+
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+Possible Output:
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+
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+ 10
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+ 389
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+
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+*/
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@(require_results)
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-uint128 :: proc(r: ^Rand = nil) -> u128 {
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+uint128 :: proc(r: ^Rand = nil) -> (val: u128) {
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a := u128(_random(r))
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b := u128(_random(r))
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c := u128(_random(r))
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@@ -80,12 +259,126 @@ uint128 :: proc(r: ^Rand = nil) -> u128 {
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return (a<<96) | (b<<64) | (c<<32) | d
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}
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-@(require_results) int31 :: proc(r: ^Rand = nil) -> i32 { return i32(uint32(r) << 1 >> 1) }
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-@(require_results) int63 :: proc(r: ^Rand = nil) -> i64 { return i64(uint64(r) << 1 >> 1) }
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-@(require_results) int127 :: proc(r: ^Rand = nil) -> i128 { return i128(uint128(r) << 1 >> 1) }
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+/*
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+Generates a random 31 bit value using the provided random number generator. If no generator is provided the global random number generator will be used.
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+The sign bit will always be set to 0, thus all generated numbers will be positive.
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+
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+Inputs:
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+- r: The random number generator to use, or nil for the global generator
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+
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+Returns:
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+- val: A random 31 bit value
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ int31_example :: proc() {
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+ // Using the global random number generator
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+ fmt.println(rand.int31())
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+ // Using local random number generator
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+ my_rand := rand.create(1)
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+ fmt.println(rand.int31(&my_rand))
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+ }
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+
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+Possible Output:
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+
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+ 10
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+ 389
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+
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+*/
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+@(require_results) int31 :: proc(r: ^Rand = nil) -> (val: i32) { return i32(uint32(r) << 1 >> 1) }
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+/*
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+Generates a random 63 bit value using the provided random number generator. If no generator is provided the global random number generator will be used.
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+The sign bit will always be set to 0, thus all generated numbers will be positive.
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+
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+Inputs:
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+- r: The random number generator to use, or nil for the global generator
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+
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+Returns:
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+- val: A random 63 bit value
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ int63_example :: proc() {
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+ // Using the global random number generator
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+ fmt.println(rand.int63())
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+ // Using local random number generator
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+ my_rand := rand.create(1)
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+ fmt.println(rand.int63(&my_rand))
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+ }
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+
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+Possible Output:
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+ 10
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+ 389
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+
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+*/
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+@(require_results) int63 :: proc(r: ^Rand = nil) -> (val: i64) { return i64(uint64(r) << 1 >> 1) }
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+/*
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+Generates a random 127 bit value using the provided random number generator. If no generator is provided the global random number generator will be used.
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+The sign bit will always be set to 0, thus all generated numbers will be positive.
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+
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+Inputs:
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+- r: The random number generator to use, or nil for the global generator
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+
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+Returns:
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+- val: A random 127 bit value
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ int127_example :: proc() {
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+ // Using the global random number generator
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+ fmt.println(rand.int127())
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+ // Using local random number generator
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+ my_rand := rand.create(1)
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+ fmt.println(rand.int127(&my_rand))
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+ }
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+
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+Possible Output:
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+
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+ 10
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+ 389
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+
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+*/
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+@(require_results) int127 :: proc(r: ^Rand = nil) -> (val: i128) { return i128(uint128(r) << 1 >> 1) }
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+
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+/*
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+Generates a random 31 bit value in the range `(0, n]` using the provided random number generator. If no generator is provided the global random number generator will be used.
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+
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+Inputs:
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+- n: The upper bound of the generated number, this value is exclusive
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+- r: The random number generator to use, or nil for the global generator
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+
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+Returns:
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+- val: A random 31 bit value in the range `(0, n]`
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+
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+WARNING: Panics if n is less than 0
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ int31_max_example :: proc() {
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+ // Using the global random number generator
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+ fmt.println(rand.int31_max(16))
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+ // Using local random number generator
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+ my_rand := rand.create(1)
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+ fmt.println(rand.int31_max(1024, &my_rand))
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+ }
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+
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+Possible Output:
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+
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+ 6
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+ 500
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+
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+*/
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@(require_results)
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-int31_max :: proc(n: i32, r: ^Rand = nil) -> i32 {
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+int31_max :: proc(n: i32, r: ^Rand = nil) -> (val: i32) {
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if n <= 0 {
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panic("Invalid argument to int31_max")
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}
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@@ -99,9 +392,38 @@ int31_max :: proc(n: i32, r: ^Rand = nil) -> i32 {
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}
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return v % n
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}
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+/*
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+Generates a random 63 bit value in the range `(0, n]` using the provided random number generator. If no generator is provided the global random number generator will be used.
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+
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+Inputs:
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+- n: The upper bound of the generated number, this value is exclusive
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+- r: The random number generator to use, or nil for the global generator
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+
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+Returns:
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+- val: A random 63 bit value in the range `(0, n]`
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+
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+WARNING: Panics if n is less than 0
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ int63_max_example :: proc() {
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+ // Using the global random number generator
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+ fmt.println(rand.int63_max(16))
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+ // Using local random number generator
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+ my_rand := rand.create(1)
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+ fmt.println(rand.int63_max(1024, &my_rand))
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+ }
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+
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+Possible Output:
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+
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+ 6
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+ 500
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+
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+*/
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@(require_results)
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-int63_max :: proc(n: i64, r: ^Rand = nil) -> i64 {
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+int63_max :: proc(n: i64, r: ^Rand = nil) -> (val: i64) {
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if n <= 0 {
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panic("Invalid argument to int63_max")
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}
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@@ -115,9 +437,38 @@ int63_max :: proc(n: i64, r: ^Rand = nil) -> i64 {
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}
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return v % n
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}
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+/*
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+Generates a random 127 bit value in the range `(0, n]` using the provided random number generator. If no generator is provided the global random number generator will be used.
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+
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+Inputs:
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+- n: The upper bound of the generated number, this value is exclusive
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+- r: The random number generator to use, or nil for the global generator
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+
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+Returns:
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+- val: A random 127 bit value in the range `(0, n]`
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+
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+WARNING: Panics if n is less than 0
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+
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+Example:
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+ import "core:math/rand"
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+ import "core:fmt"
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+
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+ int127_max_example :: proc() {
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+ // Using the global random number generator
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+ fmt.println(rand.int127_max(16))
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+ // Using local random number generator
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+ my_rand := rand.create(1)
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+ fmt.println(rand.int127_max(1024, &my_rand))
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+ }
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+
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+Possible Output:
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+ 6
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+ 500
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+
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+*/
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@(require_results)
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-int127_max :: proc(n: i128, r: ^Rand = nil) -> i128 {
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+int127_max :: proc(n: i128, r: ^Rand = nil) -> (val: i128) {
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if n <= 0 {
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panic("Invalid argument to int127_max")
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}
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@@ -131,9 +482,38 @@ int127_max :: proc(n: i128, r: ^Rand = nil) -> i128 {
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}
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return v % n
|
|
|
}
|
|
|
+/*
|
|
|
+Generates a random integer value in the range `(0, n]` using the provided random number generator. If no generator is provided the global random number generator will be used.
|
|
|
+
|
|
|
+Inputs:
|
|
|
+- n: The upper bound of the generated number, this value is exclusive
|
|
|
+- r: The random number generator to use, or nil for the global generator
|
|
|
+
|
|
|
+Returns:
|
|
|
+- val: A random integer value in the range `(0, n]`
|
|
|
|
|
|
+WARNING: Panics if n is less than 0
|
|
|
+
|
|
|
+Example:
|
|
|
+ import "core:math/rand"
|
|
|
+ import "core:fmt"
|
|
|
+
|
|
|
+ int_max_example :: proc() {
|
|
|
+ // Using the global random number generator
|
|
|
+ fmt.println(rand.int_max(16))
|
|
|
+ // Using local random number generator
|
|
|
+ my_rand := rand.create(1)
|
|
|
+ fmt.println(rand.int_max(1024, &my_rand))
|
|
|
+ }
|
|
|
+
|
|
|
+Possible Output:
|
|
|
+
|
|
|
+ 6
|
|
|
+ 500
|
|
|
+
|
|
|
+*/
|
|
|
@(require_results)
|
|
|
-int_max :: proc(n: int, r: ^Rand = nil) -> int {
|
|
|
+int_max :: proc(n: int, r: ^Rand = nil) -> (val: int) {
|
|
|
if n <= 0 {
|
|
|
panic("Invalid argument to int_max")
|
|
|
}
|
|
@@ -144,14 +524,153 @@ int_max :: proc(n: int, r: ^Rand = nil) -> int {
|
|
|
}
|
|
|
}
|
|
|
|
|
|
-// Uniform random distribution [0, 1)
|
|
|
-@(require_results) float64 :: proc(r: ^Rand = nil) -> f64 { return f64(int63_max(1<<53, r)) / (1 << 53) }
|
|
|
-// Uniform random distribution [0, 1)
|
|
|
-@(require_results) float32 :: proc(r: ^Rand = nil) -> f32 { return f32(float64(r)) }
|
|
|
+/*
|
|
|
+Generates a random double floating point value in the range `(0, 1]` using the provided random number generator. If no generator is provided the global random number generator will be used.
|
|
|
+
|
|
|
+Inputs:
|
|
|
+- r: The random number generator to use, or nil for the global generator
|
|
|
+
|
|
|
+Returns:
|
|
|
+- val: A random double floating point value in the range `(0, 1]`
|
|
|
+
|
|
|
+Example:
|
|
|
+ import "core:math/rand"
|
|
|
+ import "core:fmt"
|
|
|
+
|
|
|
+ float64_example :: proc() {
|
|
|
+ // Using the global random number generator
|
|
|
+ fmt.println(rand.float64())
|
|
|
+ // Using local random number generator
|
|
|
+ my_rand := rand.create(1)
|
|
|
+ fmt.println(rand.float64(&my_rand))
|
|
|
+ }
|
|
|
+
|
|
|
+Possible Output:
|
|
|
+
|
|
|
+ 0.043
|
|
|
+ 0.511
|
|
|
+
|
|
|
+*/
|
|
|
+@(require_results) float64 :: proc(r: ^Rand = nil) -> (val: f64) { return f64(int63_max(1<<53, r)) / (1 << 53) }
|
|
|
+
|
|
|
+/*
|
|
|
+Generates a random single floating point value in the range `(0, 1]` using the provided random number generator. If no generator is provided the global random number generator will be used.
|
|
|
+
|
|
|
+Inputs:
|
|
|
+- r: The random number generator to use, or nil for the global generator
|
|
|
+
|
|
|
+Returns:
|
|
|
+- val: A random single floating point value in the range `(0, 1]`
|
|
|
+
|
|
|
+Example:
|
|
|
+ import "core:math/rand"
|
|
|
+ import "core:fmt"
|
|
|
+
|
|
|
+ float32_example :: proc() {
|
|
|
+ // Using the global random number generator
|
|
|
+ fmt.println(rand.float32())
|
|
|
+ // Using local random number generator
|
|
|
+ my_rand := rand.create(1)
|
|
|
+ fmt.println(rand.float32(&my_rand))
|
|
|
+ }
|
|
|
+
|
|
|
+Possible Output:
|
|
|
+
|
|
|
+ 0.043
|
|
|
+ 0.511
|
|
|
+
|
|
|
+*/
|
|
|
+@(require_results) float32 :: proc(r: ^Rand = nil) -> (val: f32) { return f32(float64(r)) }
|
|
|
+
|
|
|
+/*
|
|
|
+Generates a random double floating point value in the range `(low, high]` using the provided random number generator. If no generator is provided the global random number generator will be used.
|
|
|
+
|
|
|
+Inputs:
|
|
|
+- low: The lower bounds of the value, this value is inclusive
|
|
|
+- high: The upper bounds of the value, this value is exclusive
|
|
|
+- r: The random number generator to use, or nil for the global generator
|
|
|
+
|
|
|
+Returns:
|
|
|
+- val: A random double floating point value in the range `(low, high]`
|
|
|
+
|
|
|
+Example:
|
|
|
+ import "core:math/rand"
|
|
|
+ import "core:fmt"
|
|
|
+
|
|
|
+ float64_range_example :: proc() {
|
|
|
+ // Using the global random number generator
|
|
|
+ fmt.println(rand.float64_range(-10, 300))
|
|
|
+ // Using local random number generator
|
|
|
+ my_rand := rand.create(1)
|
|
|
+ fmt.println(rand.float64_range(600, 900, &my_rand))
|
|
|
+ }
|
|
|
+
|
|
|
+Possible Output:
|
|
|
|
|
|
-@(require_results) float64_range :: proc(lo, hi: f64, r: ^Rand = nil) -> f64 { return (hi-lo)*float64(r) + lo }
|
|
|
-@(require_results) float32_range :: proc(lo, hi: f32, r: ^Rand = nil) -> f32 { return (hi-lo)*float32(r) + lo }
|
|
|
+ 15.312
|
|
|
+ 673.130
|
|
|
|
|
|
+*/
|
|
|
+@(require_results) float64_range :: proc(low, high: f64, r: ^Rand = nil) -> (val: f64) { return (high-low)*float64(r) + low }
|
|
|
+/*
|
|
|
+Generates a random single floating point value in the range `(low, high]` using the provided random number generator. If no generator is provided the global random number generator will be used.
|
|
|
+
|
|
|
+Inputs:
|
|
|
+- low: The lower bounds of the value, this value is inclusive
|
|
|
+- high: The upper bounds of the value, this value is exclusive
|
|
|
+- r: The random number generator to use, or nil for the global generator
|
|
|
+
|
|
|
+Returns:
|
|
|
+- val: A random single floating point value in the range `(low, high]`
|
|
|
+
|
|
|
+Example:
|
|
|
+ import "core:math/rand"
|
|
|
+ import "core:fmt"
|
|
|
+
|
|
|
+ float32_range_example :: proc() {
|
|
|
+ // Using the global random number generator
|
|
|
+ fmt.println(rand.float32_range(-10, 300))
|
|
|
+ // Using local random number generator
|
|
|
+ my_rand := rand.create(1)
|
|
|
+ fmt.println(rand.float32_range(600, 900, &my_rand))
|
|
|
+ }
|
|
|
+
|
|
|
+Possible Output:
|
|
|
+
|
|
|
+ 15.312
|
|
|
+ 673.130
|
|
|
+
|
|
|
+*/
|
|
|
+@(require_results) float32_range :: proc(low, high: f32, r: ^Rand = nil) -> (val: f32) { return (high-low)*float32(r) + low }
|
|
|
+
|
|
|
+/*
|
|
|
+Fills a byte slice with random values using the provided random number generator. If no generator is provided the global random number generator will be used.
|
|
|
+
|
|
|
+Inputs:
|
|
|
+- p: The byte slice to fill
|
|
|
+- r: The random number generator to use, or nil for the global generator
|
|
|
+
|
|
|
+Returns:
|
|
|
+- n: The number of bytes generated
|
|
|
+
|
|
|
+Example:
|
|
|
+ import "core:math/rand"
|
|
|
+ import "core:fmt"
|
|
|
+
|
|
|
+ read_example :: proc() {
|
|
|
+ // Using the global random number generator
|
|
|
+ data: [8]byte
|
|
|
+ n := rand.read(data[:])
|
|
|
+ fmt.println(n)
|
|
|
+ fmt.println(data)
|
|
|
+ }
|
|
|
+
|
|
|
+Possible Output:
|
|
|
+
|
|
|
+ 8
|
|
|
+ [32, 4, 59, 7, 1, 2, 2, 119]
|
|
|
+
|
|
|
+*/
|
|
|
@(require_results)
|
|
|
read :: proc(p: []byte, r: ^Rand = nil) -> (n: int) {
|
|
|
pos := i8(0)
|
|
@@ -168,19 +687,81 @@ read :: proc(p: []byte, r: ^Rand = nil) -> (n: int) {
|
|
|
return
|
|
|
}
|
|
|
|
|
|
-// perm returns a slice of n ints in a pseudo-random permutation of integers in the range [0, n)
|
|
|
+/*
|
|
|
+Creates a slice of `int` filled with random values using the provided random number generator. If no generator is provided the global random number generator will be used.
|
|
|
+
|
|
|
+*Allocates Using Provided Allocator*
|
|
|
+
|
|
|
+Inputs:
|
|
|
+- n: The size of the created slice
|
|
|
+- r: The random number generator to use, or nil for the global generator
|
|
|
+- allocator: (default: context.allocator)
|
|
|
+
|
|
|
+Returns:
|
|
|
+- res: A slice filled with random values
|
|
|
+- err: An allocator error if one occured, `nil` otherwise
|
|
|
+
|
|
|
+Example:
|
|
|
+ import "core:math/rand"
|
|
|
+ import "core:mem"
|
|
|
+ import "core:fmt"
|
|
|
+
|
|
|
+ perm_example :: proc() -> (err: mem.Allocator_Error) {
|
|
|
+ // Using the global random number generator and using the context allocator
|
|
|
+ data := rand.perm(4) or_return
|
|
|
+ fmt.println(data)
|
|
|
+ defer delete(data, context.allocator)
|
|
|
+
|
|
|
+ // Using local random number generator and temp allocator
|
|
|
+ my_rand := rand.create(1)
|
|
|
+ data_tmp := rand.perm(4, &my_rand, context.temp_allocator) or_return
|
|
|
+ fmt.println(data_tmp)
|
|
|
+
|
|
|
+ return
|
|
|
+ }
|
|
|
+
|
|
|
+Possible Output:
|
|
|
+
|
|
|
+ [7201011, 3, 9123, 231131]
|
|
|
+ [19578, 910081, 131, 7]
|
|
|
+
|
|
|
+*/
|
|
|
@(require_results)
|
|
|
-perm :: proc(n: int, r: ^Rand = nil, allocator := context.allocator) -> []int {
|
|
|
- m := make([]int, n, allocator)
|
|
|
+perm :: proc(n: int, r: ^Rand = nil, allocator := context.allocator) -> (res: []int, err: mem.Allocator_Error) #optional_allocator_error {
|
|
|
+ m := make([]int, n, allocator) or_return
|
|
|
for i := 0; i < n; i += 1 {
|
|
|
j := int_max(i+1, r)
|
|
|
m[i] = m[j]
|
|
|
m[j] = i
|
|
|
}
|
|
|
- return m
|
|
|
+ return m, {}
|
|
|
}
|
|
|
|
|
|
+/*
|
|
|
+Randomizes the ordering of elements for the provided slice. If no generator is provided the global random number generator will be used.
|
|
|
+
|
|
|
+Inputs:
|
|
|
+- array: The slice to randomize
|
|
|
+- r: The random number generator to use, or nil for the global generator
|
|
|
+
|
|
|
+Example:
|
|
|
+ import "core:math/rand"
|
|
|
+ import "core:fmt"
|
|
|
+
|
|
|
+ shuffle_example :: proc() {
|
|
|
+ // Using the global random number generator
|
|
|
+ data: [4]int = { 1, 2, 3, 4 }
|
|
|
+ fmt.println(data) // the contents are in order
|
|
|
+ rand.shuffle(data[:])
|
|
|
+ fmt.println(data) // the contents have been shuffled
|
|
|
+ }
|
|
|
+
|
|
|
+Possible Output:
|
|
|
|
|
|
+ [1, 2, 3, 4]
|
|
|
+ [2, 4, 3, 1]
|
|
|
+
|
|
|
+*/
|
|
|
shuffle :: proc(array: $T/[]$E, r: ^Rand = nil) {
|
|
|
n := i64(len(array))
|
|
|
if n < 2 {
|
|
@@ -193,7 +774,38 @@ shuffle :: proc(array: $T/[]$E, r: ^Rand = nil) {
|
|
|
}
|
|
|
}
|
|
|
|
|
|
-// Returns a random element from the given slice
|
|
|
+/*
|
|
|
+Returns a random element from the provided slice. If no generator is provided the global random number generator will be used.
|
|
|
+
|
|
|
+Inputs:
|
|
|
+- array: The slice to choose an element from
|
|
|
+- r: The random number generator to use, or nil for the global generator
|
|
|
+
|
|
|
+Returns:
|
|
|
+- res: A random element from `array`
|
|
|
+
|
|
|
+Example:
|
|
|
+ import "core:math/rand"
|
|
|
+ import "core:fmt"
|
|
|
+
|
|
|
+ choice_example :: proc() {
|
|
|
+ // Using the global random number generator
|
|
|
+ data: [4]int = { 1, 2, 3, 4 }
|
|
|
+ fmt.println(rand.choice(data[:]))
|
|
|
+ fmt.println(rand.choice(data[:]))
|
|
|
+ fmt.println(rand.choice(data[:]))
|
|
|
+ fmt.println(rand.choice(data[:]))
|
|
|
+ }
|
|
|
+
|
|
|
+
|
|
|
+Possible Output:
|
|
|
+
|
|
|
+ 3
|
|
|
+ 2
|
|
|
+ 2
|
|
|
+ 4
|
|
|
+
|
|
|
+*/
|
|
|
@(require_results)
|
|
|
choice :: proc(array: $T/[]$E, r: ^Rand = nil) -> (res: E) {
|
|
|
n := i64(len(array))
|
|
@@ -201,4 +813,4 @@ choice :: proc(array: $T/[]$E, r: ^Rand = nil) -> (res: E) {
|
|
|
return E{}
|
|
|
}
|
|
|
return array[int63_max(n, r)]
|
|
|
-}
|
|
|
+}
|