Well, if bcpow has limits, then this should work:
<?php
function bcpow_($num, $power) {
$awnser = "1";
while ($power) {
$awnser = bcmul($awnser, $num, 100);
$power = bcsub($power, "1");
}
return rtrim($awnser, '0.');
}
?>
Just that $power cannot have decimal digits in it.
bcpow
(PHP 4, PHP 5, PHP 7)
bcpow — 임의 정밀도 수 거듭제곱
설명
string bcpow
( string
$left_operand
, string $right_operand
[, int $scale
] )
left_operand를
right_operand제곱합니다.
인수
-
left_operand -
왼쪽 연산수, 문자열.
-
right_operand -
오른쪽 연산수, 문자열.
-
scale -
이 선택적인 인수는 소수점 아래 자리수를 설정합니다. bcscale()을 사용하여 모든 함수에 대한 전역 기본값을 설정할 수 있습니다.
반환값
결과를 문자열로 반환합니다.
예제
Example #1 bcpow() 예제
<?php
echo bcpow('4.2', '3', 2); // 74.08
?>
add a note
User Contributed Notes 3 notes
Anonymous ¶
19 years ago
Michael Bailey (jinxidoru at byu dot net) ¶
20 years ago
bcpow() only supports exponents less than or equal to 2^31-1. Also, bcpow() does not support decimal numbers. If you have scale set to 0, then the exponent is converted to an interger; otherwise an error is generated.
--
Michael Bailey
http://www.jinxidoru.com
thomas at tgohome dot com ¶
15 years ago
<?php
bcscale(100);
/*
* Computes the natural logarithm using a series.
* @author Thomas Oldbury.
* @license Public domain.
*/
function bcln($a, $iter = 10)
{
$result = "0.0";
for($i = 0; $i < $iter; $i++)
{
$pow = (1 + (2 * $i));
$mul = bcdiv("1.0", $pow);
$fraction = bcmul($mul, bcpow(bcsub($a, "1.0") / bcadd($a, "1.0"), $pow));
$result = bcadd($fraction, $result);
}
return bcmul("2.0", $result);
}
/*
* Computes the base2 log using baseN log.
* @note Requires above functions.
* @author Thomas Oldbury.
* @license Public domain.
*/
function bclog2($a, $iter = 10)
{
return bcdiv(bcln($a, $iter), bcln("2", $iter));
}
/*
* Computes the base10 log using baseN log.
* @note Requires above functions.
* @author Thomas Oldbury.
* @license Public domain.
*/
function bclog10($a, $iter = 10)
{
return bcdiv(bcln($a, $iter), bcln("10", $iter));
}
?>
