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Merge branch 'PHP-8.3'

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* PHP-8.3:
  random: Fix γ-section implementation for Randomizer::getFloat() (#12402)
This commit is contained in:
Tim Düsterhus
2023-10-13 18:04:40 +02:00
parent b11af37a3f 582b724c35
commit 82c2143ddb
3 changed files with 150 additions and 8 deletions
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65
ext/random/gammasection.c
View File

@@ -13,6 +13,9 @@
| Authors: Tim Düsterhus <timwolla@php.net> |
| |
| Based on code from: Frédéric Goualard |
| Corrected to handled appropriately random integers larger than 2^53 |
| converted to double precision floats, and to avoid overflows for |
| large gammas. |
+----------------------------------------------------------------------+
*/
@@ -46,6 +49,12 @@ static double gamma_max(double x, double y)
return (fabs(x) > fabs(y)) ? gamma_high(x) : gamma_low(y);
}
static void splitint64(uint64_t v, double *vhi, double *vlo)
{
*vhi = v >> 2;
*vlo = v & UINT64_C(0x3);
}
static uint64_t ceilint(double a, double b, double g)
{
double s = b / g - a / g;
@@ -74,9 +83,19 @@ PHPAPI double php_random_gammasection_closed_open(const php_random_algo *algo, p
uint64_t k = 1 + php_random_range64(algo, status, hi - 1); /* [1, hi] */
if (fabs(min) <= fabs(max)) {
return k == hi ? min : max - k * g;
if (k == hi) {
return min;
} else {
double k_hi, k_lo;
splitint64(k, &k_hi, &k_lo);
return 0x1p+2 * (max * 0x1p-2 - k_hi * g) - k_lo * g;
}
} else {
return min + (k - 1) * g;
double k_hi, k_lo;
splitint64(k - 1, &k_hi, &k_lo);
return 0x1p+2 * (min * 0x1p-2 + k_hi * g) + k_lo * g;
}
}
@@ -92,9 +111,23 @@ PHPAPI double php_random_gammasection_closed_closed(const php_random_algo *algo,
uint64_t k = php_random_range64(algo, status, hi); /* [0, hi] */
if (fabs(min) <= fabs(max)) {
return k == hi ? min : max - k * g;
if (k == hi) {
return min;
} else {
double k_hi, k_lo;
splitint64(k, &k_hi, &k_lo);
return 0x1p+2 * (max * 0x1p-2 - k_hi * g) - k_lo * g;
}
} else {
return k == hi ? max : min + k * g;
if (k == hi) {
return max;
} else {
double k_hi, k_lo;
splitint64(k, &k_hi, &k_lo);
return 0x1p+2 * (min * 0x1p-2 + k_hi * g) + k_lo * g;
}
}
}
@@ -110,9 +143,19 @@ PHPAPI double php_random_gammasection_open_closed(const php_random_algo *algo, p
uint64_t k = php_random_range64(algo, status, hi - 1); /* [0, hi - 1] */
if (fabs(min) <= fabs(max)) {
return max - k * g;
double k_hi, k_lo;
splitint64(k, &k_hi, &k_lo);
return 0x1p+2 * (max * 0x1p-2 - k_hi * g) - k_lo * g;
} else {
return k == (hi - 1) ? max : min + (k + 1) * g;
if (k == (hi - 1)) {
return max;
} else {
double k_hi, k_lo;
splitint64(k + 1, &k_hi, &k_lo);
return 0x1p+2 * (min * 0x1p-2 + k_hi * g) + k_lo * g;
}
}
}
@@ -128,8 +171,14 @@ PHPAPI double php_random_gammasection_open_open(const php_random_algo *algo, php
uint64_t k = 1 + php_random_range64(algo, status, hi - 2); /* [1, hi - 1] */
if (fabs(min) <= fabs(max)) {
return max - k * g;
double k_hi, k_lo;
splitint64(k, &k_hi, &k_lo);
return 0x1p+2 * (max * 0x1p-2 - k_hi * g) - k_lo * g;
} else {
return min + k * g;
double k_hi, k_lo;
splitint64(k, &k_hi, &k_lo);
return 0x1p+2 * (min * 0x1p-2 + k_hi * g) + k_lo * g;
}
}

41
ext/random/tests/03_randomizer/methods/getFloat_extreme_range.phpt Normal file
View File

@@ -0,0 +1,41 @@
--TEST--
Random: Randomizer: getFloat(): Extreme ranges are handled correctly
--FILE--
<?php
use Random\Engine;
use Random\Randomizer;
final class TestEngine implements Engine
{
private array $values = [
"\x64\xe8\x58\x79\x3e\xf6\x38\x00",
"\x65\xe8\x58\x79\x3e\xf6\x38\x00",
"\x00\x00\x00\x00\x00\x00\x00\x00",
];
public function generate(): string
{
return \array_shift($this->values);
}
}
$r = new Randomizer(new TestEngine());
$min = -1.6e308;
$max = 1.6e308;
printf("%.17g\n", $min);
printf("%.17g\n\n", $max);
printf("%.17g\n", $r->getFloat($min, $max));
printf("%.17g\n", $r->getFloat($min, $max));
printf("%.17g\n", $r->getFloat($min, $max));
?>
--EXPECT--
-1.6e+308
1.6e+308
-1.5999999999999998e+308
-1.6e+308
1.5999999999999998e+308

52
ext/random/tests/03_randomizer/methods/getFloat_opposite_signs.phpt Normal file
View File

@@ -0,0 +1,52 @@
--TEST--
Random: Randomizer: getFloat(): Opposite signs are handled correctly
--FILE--
<?php
use Random\Engine;
use Random\Randomizer;
final class TestEngine implements Engine
{
private array $values = [
"\x63\xe8\x58\x79\x3e\xf6\x38\x00",
"\x64\xe8\x58\x79\x3e\xf6\x38\x00",
"\x65\xe8\x58\x79\x3e\xf6\x38\x00",
"\x66\xe8\x58\x79\x3e\xf6\x38\x00",
"\x67\xe8\x58\x79\x3e\xf6\x38\x00",
];
public function generate(): string
{
return \array_shift($this->values);
}
}
$r = new Randomizer(new TestEngine());
$min = -1;
$max = 1;
printf("%.17g\n", $min);
printf("%.17g\n\n", $max);
$prev = null;
for ($i = 0; $i < 5; $i++) {
$float = $r->getFloat($min, $max);
printf("%.17f", $float);
if ($prev !== null) {
printf(" (%+.17g)", ($float - $prev));
}
printf("\n");
$prev = $float;
}
?>
--EXPECT--
-1
1
-0.78005908680576086
-0.78005908680576097 (-1.1102230246251565e-16)
-0.78005908680576108 (-1.1102230246251565e-16)
-0.78005908680576119 (-1.1102230246251565e-16)
-0.78005908680576130 (-1.1102230246251565e-16)