#!/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";
}

##</code><code>##

  0: 0.0345, 0.9916, 0.0013
  1: 0.0499, 0.9876, 0.0011
  2: 0.1340, 0.9659, 0.0012
  3: 0.1635, 0.9578, 0.0011
  4: 0.2149, 0.9412, 0.0047
  5: 0.2911, 0.9215, 0.0015
  6: 0.2974, 0.9186, 0.0010
  7: 0.3617, 0.8983, 0.0018
  8: 0.4183, 0.8819, 0.0010
  9: 0.4535, 0.8672, 0.0085
 10: 0.5317, 0.8421, 0.0010
 11: 0.5689, 0.8306, 0.0040
 12: 0.5995, 0.8179, 0.0056
 13: 
 14: 
 15: 
 16: 0.8015, 0.7142, 0.0249
 17: 0.8540, 0.6901, 0.0060
 18: 0.9126, 0.6475, 0.0020
 19: 0.9690, 0.5879, 0.0023