Write-Pi

Writes PI

Script

param([int]$digits = 1000)

function Write-Pi ( $digits ) {
	$Big = [bigint[]](0..10)
 
	$ndigits = 0
 
 	$q = $t = $k = $Big[1]
 	$r =           $Big[0]
	$l = $n =      $Big[3]

	# calculate first digit
	$nr = ( $Big[2] * $q + $r ) * $l
	$nn = ( $q * ( $Big[7] * $k + $Big[2] ) + $r * $l ) / ( $t * $l )
	$q *= $k
	$t *= $l
	$l += $Big[2]
	$k = $k + $Big[1]
	$n = $nn
	$r = $nr
 
 	Write-Host "$($n)." -noNewline
 	$ndigits++
 
 	$nr = $Big[10] * ( $r - $n * $t )
 	$n = ( ( $Big[10] * ( 3 * $q + $r ) ) / $t ) - 10 * $n
 	$q *= $Big[10]
 	$r = $nr
 
 	while ($ndigits -lt $digits) {
		if ($Big[4] * $q + $r - $t -lt $n * $t) {
			Write-Host "$n" -noNewline
			$ndigits++
			$nr = $Big[10] * ( $r - $n * $t )
			$n = ( ( $Big[10] * ( 3 * $q + $r ) ) / $t ) - 10 * $n
			$q *= $Big[10]
			$r = $nr
		} else {
			$nr = ( $Big[2] * $q + $r ) * $l
			$nn = ( $q * ( $Big[7] * $k + $Big[2] ) + $r * $l ) / ( $t * $l )
			$q *= $k
			$t *= $l
			$l += $Big[2]
			$k = $k + $Big[1]
			$n = $nn
			$r = $nr
		}
      }
	Write-Host "...  ($digits digits)"
}

try {
	Write-Pi $digits
	exit 0 # success
} catch {
	"?? ERROR: $($Error[0]) (script line $($_.InvocationInfo.ScriptLineNumber))"
	exit 1
}

Customize

digits int

Specifies the number of digits to list (1000 by default)