bcmul
<?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));
}
?>
bcpow
(PHP 4, PHP 5)
bcpow — Raise an arbitrary precision number to another
Descrierea
string bcpow
( string $left_operand
, string $right_operand
[, int $scale
] )
Raise left_operand to the power right_operand .
Parametri
- left_operand
-
The left operand, as a string.
- right_operand
-
The right operand, as a string.
- scale
-
Acest parametru opţional este utilizat pentru a stabili numărul cifrelor după virgulă din rezultat. De asemenea puteţi să stabiliţi parametrul global scale pentru toate funcţiile utilizând bcscale().
Valorile întroarse
Returns the result as a string.
Exemple
Example #1 bcpow() example
<?php
echo bcpow('4.2', '3', 2); // 74.08
?>
Vedeţi de asemenea
- bcpowmod() - Raise an arbitrary precision number to another, reduced by a specified modulus
- bcsqrt() - Get the square root of an arbitrary precision number
add a note
User Contributed Notesbcpow
thomas at tgohome dot com
13-Jul-2009 07:19
13-Jul-2009 07:19
11-Feb-2005 09:58
Well, if bcpow has limits, then this should work:
<?php
function bcpow_($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.
Michael Bailey (jinxidoru at byu dot net)
10-Aug-2004 12:42
10-Aug-2004 12:42
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