SunshinePHP Developer Conference 2015

bcpow

(PHP 4, PHP 5)

bcpowعددی با دقت دلخواه به توان عدد دیگر

Description

string bcpow ( string $left_operand , string $right_operand [, int $scale ] )

left_operand به توان right_operand.

Parameters

left_operand

عملوند چپ به عنوان رشته.

right_operand

عملوند راست به عنوان رشته.

scale

This optional parameter is used to set the number of digits after the decimal place in the result. You can also set the global default scale for all functions by using bcscale().

Return Values

بازگرداندن نتیجه به عنوان رشته.

Examples

Example #1 مثال bcpow()

<?php

echo bcpow('4.2''3'2); // 74.08

?>

See Also

  • bcpowmod() - Raise an arbitrary precision number to another, reduced by a specified modulus
  • bcsqrt() - دریافت ریشه عدد با دقت دلخواه

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User Contributed Notes 3 notes

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1
Michael Bailey (jinxidoru at byu dot net)
10 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
up
0
thomas at tgohome dot com
5 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));
}


?>
up
0
Anonymous
9 years ago
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.
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