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Add gmp_binomial()

Adds PHP bindings for mpz_bin_ui and mpz_bin_uiui, for calculating
binomial coefficients.
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nikic committed Dec 9, 2017
1 parent dc47171 commit 7fea79675cfb064726f3fc7845e2c2bb1f247ea5
Showing with 103 additions and 0 deletions.
  1. +1 −0 NEWS
  2. +3 −0 UPGRADING
  3. +31 −0 ext/gmp/gmp.c
  4. +1 −0 ext/gmp/php_gmp.h
  5. +67 −0 ext/gmp/tests/gmp_binomial.phpt
1 NEWS
@@ -48,6 +48,7 @@ PHP NEWS
- GMP:
. Export internal structures and accessor helpers for GMP object. (Sara)
. Added gmp_binomial(n, k). (Nikita)
- intl:
. Fixed bug #75317 (UConverter::setDestinationEncoding changes source instead
@@ -85,6 +85,9 @@ Date:
. Added the DateTime::createFromImmutable() method, which mirrors
DateTimeImmutable::createFromMutable().
GMP:
. Added gmp_binomial(n, k) for calculating binomial coefficients.
Intl:
. Added void Spoofchecker::setRestrictionLevel(int $level) method, available
when linked with ICU >= 58.1. Levels are represented as class constants
@@ -188,6 +188,7 @@ const zend_function_entry gmp_functions[] = {
ZEND_FE(gmp_popcount, arginfo_gmp_unary)
ZEND_FE(gmp_hamdist, arginfo_gmp_binary)
ZEND_FE(gmp_nextprime, arginfo_gmp_unary)
ZEND_FE(gmp_binomial, arginfo_gmp_binary)
PHP_FE_END
};
/* }}} */
@@ -1382,6 +1383,36 @@ ZEND_FUNCTION(gmp_fact)
}
/* }}} */
/* {{{ proto GMP gmp_binomial(mixed n, int k)
* Calculates binomial coefficient */
ZEND_FUNCTION(gmp_binomial)
{
zval *n_arg;
zend_long k;
mpz_ptr gmpnum_result;
if (zend_parse_parameters(ZEND_NUM_ARGS(), "zl", &n_arg, &k) == FAILURE) {
return;
}
if (k < 0) {
php_error_docref(NULL, E_WARNING, "k cannot be negative");
RETURN_FALSE;
}
INIT_GMP_RETVAL(gmpnum_result);
if (Z_TYPE_P(n_arg) == IS_LONG && Z_LVAL_P(n_arg) >= 0) {
mpz_bin_uiui(gmpnum_result, (gmp_ulong) Z_LVAL_P(n_arg), (gmp_ulong) k);
} else {
mpz_ptr gmpnum_n;
gmp_temp_t temp_n;
FETCH_GMP_ZVAL(gmpnum_n, n_arg, temp_n);
mpz_bin_ui(gmpnum_result, gmpnum_n, (gmp_ulong) k);
FREE_GMP_TEMP(temp_n);
}
}
/* }}} */
/* {{{ proto GMP gmp_pow(mixed base, int exp)
Raise base to power exp */
ZEND_FUNCTION(gmp_pow)
@@ -78,6 +78,7 @@ ZEND_FUNCTION(gmp_testbit);
ZEND_FUNCTION(gmp_popcount);
ZEND_FUNCTION(gmp_hamdist);
ZEND_FUNCTION(gmp_nextprime);
ZEND_FUNCTION(gmp_binomial);
ZEND_BEGIN_MODULE_GLOBALS(gmp)
zend_bool rand_initialized;
@@ -0,0 +1,67 @@
--TEST--
gmp_binomial(): Binomial coefficients
--FILE--
<?php
var_dump(gmp_binomial(10, 5));
var_dump(gmp_binomial("10", 5));
$n = gmp_init(10);
var_dump(gmp_binomial($n, 5));
var_dump(gmp_binomial(10000, 100));
var_dump(gmp_binomial(0, 0));
var_dump(gmp_binomial(0, 1));
var_dump(gmp_binomial(1, 0));
var_dump(gmp_binomial(1, 1));
var_dump(gmp_binomial(-1, 5)); // == -(1 + 5 - 1 over 5)
var_dump(gmp_binomial(-2, 6)); // == (2 + 6 - 1 over 6)
var_dump(gmp_binomial(5, -2));
?>
--EXPECTF--
object(GMP)#1 (1) {
["num"]=>
string(3) "252"
}
object(GMP)#1 (1) {
["num"]=>
string(3) "252"
}
object(GMP)#2 (1) {
["num"]=>
string(3) "252"
}
object(GMP)#2 (1) {
["num"]=>
string(242) "65208469245472575695415972927215718683781335425416743372210247172869206520770178988927510291340552990847853030615947098118282371982392705479271195296127415562705948429404753632271959046657595132854990606768967505457396473467998111950929802400"
}
object(GMP)#2 (1) {
["num"]=>
string(1) "1"
}
object(GMP)#2 (1) {
["num"]=>
string(1) "0"
}
object(GMP)#2 (1) {
["num"]=>
string(1) "1"
}
object(GMP)#2 (1) {
["num"]=>
string(1) "1"
}
object(GMP)#2 (1) {
["num"]=>
string(2) "-1"
}
object(GMP)#2 (1) {
["num"]=>
string(1) "7"
}
Warning: gmp_binomial(): k cannot be negative in %s on line %d
bool(false)

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