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

my $numBuckets = 20;
my @points =
    map {{x => $_->[0], 'y' => $_->[1], dy => $_->[2]}}
    map {chomp; [split]} <DATA>;
my @buckets;
my $min = $points[0]{x};
my $max = $points[0]{x};

for my $point (@points) {
    $min = $point->{x} if $min > $point->{x};
    $max = $point->{x} if $max < $point->{x};
}

my $scale = ($max - $min) / $numBuckets;

push @{$buckets[($_->{x} - $min) / $scale]}, $_ for @points;

for my $bucket (@buckets) {
    # Sort contents of bucket by weighting function
    next if !defined $bucket;
    @$bucket = sort {$a->{dy} <=> $b->{dy}} @$bucket;
}

for my $index (0 .. $numBuckets - 1) {
    printf "%3d: ", $index;
    printf "%.4f, %.4f, %.4f", @{$buckets[$index][0]}{qw(x y dy)}
        if defined $buckets[$index];
    print "\n";
}