#!/usr/bin/perl

# stats.pl
# Read STDIN and output the time/date, min, max, mean, and standard deviation
# Standard deviation algorithm shamelessly stolen from Kragen Sitaker,
# kragen@pobox.com

# Copyright 2001 John Ackermann   Version: 15 July 2001
# May be freely used provided these notices are retained, and a copy
# of any modified version that's distributed to third persons is sent
# to jra@febo.com

$Value = 0.0;
$n = 0;
$Min = 0.0;
$Max = 0.0;
$Mean = 0.0;

while ($RawIn=<STDIN>) {
   	$Value = round($RawIn * 100)/100;
	$sum += $Value;
	$sumsq += $Value ** 2;
	$n ++;
	if ($n > 1) {
		if ($Value < $Min) {$Min = $Value} endif;
		if ($Value > $Max) { $Max = $Value; } endif;
	} else {
		$Min = $Value;
		$Max = $Value
	} endif;
};
$Mean = round(($sum/$n)*100)/100;
$StdDev = round(sqrt(($sumsq - $sum ** 2 / $n)/$n)*100)/100;
print(scalar localtime(time()),"\t",$Min,"\t",$Max,"\t",$Mean,"\t",$StdDev,"\n");
sub round {
	my($number) = shift;
	return int($number +.5 * ($number <=> 0) );
	};