Question

Write a PHP program that calculate Pi.

Answer 1

Write a PHP program that calculate Pi.

PHP script is designed to be able to follow Viete's formula for calculating pi and if this script is given enough time to run, it can display 1000 digits of pi.

<?php
set_time_limit(0);
echo '<br />';
&
$digits=1000;
$pival='1';
$str1='';
while ($pirow<2000)
{
$pirow+=1;
$pisubrow=0;
$tempval='0';
while ($pisubrow<$pirow)
& {
& $tempval=bcsqrt(bcadd('2',$tempval,$digits),$digits);
& $pisubrow+=1;
& sleep(1);
& }
$tempval=bcdiv('2',$tempval,$digits);
$pival=bcmul($tempval,$pival,$digits);
unset($tempval);
$tempval=bcmul('2',$pival,$digits);
$common = array();
$length = (strlen($str1) >= strlen($tempval)) ? strlen($str1) : strlen($tempval);
for($x=0;$x<$length;$x++){
& if($str1[$x] == $tempval[$x]){
$common[] = $str1[$x];
& }else{
break;
& }
}
if ($pirow>5)
& {
& echo 'pi='.substr(join('',$common),0,-2);
& }
unset($str1);
$str1=$tempval;
unset($tempval);
echo '<p>';
flush();
sleep(1);
}
$pival=bcmul($pival,'2',$digits);
unset($pirow);
?>