#!/usr/bin/perl

use strict;
use warnings;
use Benchmark::Timer;

my $timer= new Benchmark::Timer;

my $tag = "fet inputs: " . join (',',@ARGV);

$timer->start($tag);

my (@snum,@sden,@nmul,@dmul) = ();
my ($i,$p,$power) = (0,0,0);

construct (@ARGV);

@snum = sort {$b<=>$a} @snum;
@sden = sort {$b<=>$a} @sden;

# Make the arrays equal size 
if (@snum < @sden) {
	foreach $i (@snum..$#sden) { $snum[$i] = 0;}
} else {
	foreach $i (@sden..$#snum) { $sden[$i] = 0;}
}


for $i (0..$#snum) {
	my @elements;
	if ($snum[$i] > $sden[$i]) {
		@elements = (($sden[$i]+1)..$snum[$i]);
		my ($num,$np) = multiply(\@elements);
		push(@nmul,$num);
		$power += $np;
	} elsif ($sden[$i] > $snum[$i]) {
		@elements = (($snum[$i]+1)..$sden[$i]);
		my ($den,$dp) = multiply(\@elements);
		push(@dmul,$den);
		$power -= $dp;
	}
}

my ($num,$den) = (1,1);

$num *= $_ for (@nmul);
$den *= $_ for (@dmul);

printf ("Ratio = %.17fe%d\n", $num/$den,$power);

$timer->stop($tag);
print $timer->report;


sub multiply {
	my $p = 0;
	my $x = shift;
	my $product = 1;
	for (@$x) {
		$product *= $_;
		while ($product > 1)   { $product /= 10; $p++; }
		while ($product < 0.1) { $product *= 10; $p--; }
	}
	return ($product,$p);
}

sub construct {
	my @data = @_;
	my $R1 = $data[0]+$data[1];
	my $R2 = $data[2]+$data[3];
	my $C1 = $data[0]+$data[2];
	my $C2 = $data[1]+$data[3];
	my $N  = $R1 + $R2;

	@snum = ($R1,$R2,$C1,$C2);	
	@sden = ($N,$data[0],$data[1],$data[2],$data[3]);	
}