bcpowmod
These functions DO NOT round off your values. No arbitrary precision libraries do it this way. It stops calculating after reaching scale of decimal places, which mean that your value is cut off after scale number of digits, not rounded. To do the rounding use something like this:
<?php
function bcround($number, $scale=0) {
$fix = "5";
for ($i=0;$i<$scale;$i++) $fix="0$fix";
$number = bcadd($number, "0.$fix", $scale+1);
return bcdiv($number, "1.0", $scale);
}
?>
bcscale
(PHP 4, PHP 5)
bcscale — Nastaviť východziu škálu pre všetky bc math funkcie
Popis
string bcscale
( int $scale
)
Táto funkcia nastavuje východziu škálu pre všetky následné bc math funkcie, ktoré explicitne škálu nešpecifikujú.
Example#1 bcscale() príklad
<?php
// vychodzia skala : 3
bcscale(3);
echo bcdiv(105, 6.55957); // 16.007
// toto je to iste bez bcscale()
echo bcdiv(105, 6.55957, 3); // 16.007
?>
add a note
User Contributed Notesbcscale
mwgamera at gmail dot com
05-Dec-2007 06:45
05-Dec-2007 06:45
invincible at limitedintelligence dot com
08-Feb-2006 03:50
08-Feb-2006 03:50
If you don't set the default scale, be careful when you're chaining together several BC math functions - since by default, these functions will round off your values, losing accuracy very quickly:
<?php
$a = 1.234
$b = 2.345
$c = 7.890
$ab = bcmul($a,$b); // 2
$abc = bcmul($ab,$c);
echo $abc; // 15
?>
... compare with the answer you get when you use more decimal places:
<?php
$a = 1.234
$b = 2.345
$c = 7.890
bcscale(15);
$ab = bcmul($a,$b); // 2.893730
$abc = bcmul($ab,$c);
echo $abc; // 22.83152970
?>