#!/usr/bin/perl 
use strict; 
use warnings;
use Storable;
use Statistics::Descriptive;

my @grid = @{ retrieve('grid.dat') };
my %param = %{ retrieve('param.dat') }; # rows and cols parameters

my @contaminated_walks;

for (1 .. 100) {
	my $num_walks = 100;
	my ($x, $y) = (int(rand $param{range_contx}), int(rand $param{range_conty}));
	my @walks;
	
	for (1 .. $num_walks) {
		my $steps = 100;
		my $infected;
		my $total_steps;
		
	 	#Inner loop to perform each step of a random walk  
		for (1 .. $steps) {		  
			$total_steps += my $rand_steps = (1 + int( rand 6 ));
			last if $total_steps > $steps;
			
			my $random_num = rand;
			if($random_num < 0.25) {
				for (1 .. $rand_steps) {
					$x = ($x - 1) % $param{range_contx};
					$infected += $grid[$x][$y] || 0;
				} 
			} 
			elsif ($random_num < 0.5) { 
				for (1 .. $rand_steps) {
					$x = ($x + 1) % $param{range_contx};
					$infected += $grid[$x][$y] || 0;
				} 
			} 
			elsif ($random_num < 0.75) { 
				for (1 .. $rand_steps) {
					$y = ($y - 1) % $param{range_conty};
					$infected += $grid[$x][$y] || 0;
				}  
			} 
			else { 
				for (1 .. $rand_steps) {
					$y = ($y + 1) % $param{range_conty};
					$infected += $grid[$x][$y] || 0;
				}   
			} 
		}
		push @walks, $infected;
	}
	push @contaminated_walks, scalar grep $_, @walks;
}
my $stat = Statistics::Descriptive::Sparse->new();
$stat->add_data(@contaminated_walks);

printf "min-max %d-%d mean: %.1f std. deviation: %.1f count: %d\n",
	$stat->min, $stat->max, $stat->mean, $stat->standard_deviation, $stat->count;

__END__
C:\Old_Data\perlp>perl t33.pl
min-max 34-61 mean: 50.7 std. deviation: 5.6 count: 100

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use Storable;

my $number_contaminant = 100;

my %param = (range_contx => 100,
             range_conty => 100 );

my @grid;
 
for (1 .. $number_contaminant) {  
	#random positions of the contaminants, put the random number as integrer  
	my $x = int(rand $param{range_contx});  
	my $y = int(rand $param{range_conty}); 
	redo if $grid[$x][$y]; # if already marked
	$grid[$x][$y] = 1;
}
 
store \@grid, 'grid.dat';
store \%param, 'param.dat';

##</code><code>##

#!/usr/bin/perl 
use strict; 
use warnings;
use Storable;
use Statistics::Descriptive;

my @grid = @{ retrieve('grid.dat') };
my %param = %{ retrieve('param.dat') }; # range_contx and range_conty parameters

my @contaminated_walks;

for (1 .. 100) {
	my $steps = 100;
	my $num_walks = 100;
	my ($x, $y) = (int(rand $param{range_contx}), int(rand $param{range_conty}));
	my @walks;
	
	for (1 .. $num_walks) {
		my $infected;
		
	 	#Inner loop to perform each step of a random walk  
		for (1 .. $steps) {		  
			my $random_num = rand; 
			my $steps = (1 + int( rand 6 )); 
			if($random_num < 0.25) { 
				$x = ($x - $steps) % $param{range_contx}; 
			} 
			elsif ($random_num < 0.5) { 
				$x = ($x + $steps) % $param{range_contx};
			} 
			elsif ($random_num < 0.75) { 
				$y = ($y - $steps) % $param{range_conty}; 
			} 
			else { 
				$y = ($y + $steps) % $param{range_conty}; 
			}
			
			$infected += $grid[$x][$y] || 0; 
		}
		push @walks, $infected;
	}
	push @contaminated_walks, scalar grep $_, @walks;
}

my $stat = Statistics::Descriptive::Sparse->new();
$stat->add_data(@contaminated_walks);

printf "mean: %.f std. deviation: %.f count: %d\n",
	$stat->mean, $stat->standard_deviation, $stat->count;

__END__
C:\Old_Data\perlp>perl his_stat.pl
mean: 60 std. deviation: 5 count: 100

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use List::Util qw/ shuffle /;
use Statistics::Descriptive;

my @contaminated_walks;

for (1 .. 100) {
	my $contaminated = 100;
	my $grid_rows = 100;
	my $grid_cols = 100;
	my $steps = 100;
	my $num_walks = 100;
	my @walks;
	
	for (1 .. $num_walks) {
		my @grid = # 1's and 0's randomly ordered
			shuffle( (1) x $contaminated, 
					 (0) x ($grid_rows * $grid_cols - $contaminated)
				   );
		
		# for each walk, 'grep' gets the count of contaminated cells
		push @walks, scalar grep $_, map $grid[rand @grid], 1 .. $steps;
	}
	push @contaminated_walks, scalar grep $_, @walks;
}

my $stat = Statistics::Descriptive::Sparse->new();
$stat->add_data(@contaminated_walks);

printf "mean: %.f std. deviation: %.f count: %d\n",
	$stat->mean, $stat->standard_deviation, $stat->count;

__END__
C:\Old_Data\perlp>perl my_stat.pl
mean: 64 std. deviation: 5 count: 100