conjunction_generator.pl

基于稀疏网络的精选机器学习模型

#!/local/all/perl
#
# script name:    conjunction_generator.pl
# author:         Nick Rizzolo
# last modified:  6/25/03
# description:    Use this script to generate every possible SNoW example over
#                 a conjunctive boolean feature space.
# arguments:
# - <variables>:  The maximum number of variables that can be active in a
#                 training or testing example.  In other words, the
#                 dimensionality of the feature space (excluding target IDs).
# - <var#>:       Each <var#> argument represents the zero-based integer index
#                 of another variable in the conjunctive concept and must be
#                 less than the value of the <variables> argument.
# output:         Every SNoW example over the feature space labeled according
#                 to the boolean function that is the conjunction of the
#                 variables specified by the <var#> arguments.  The target IDs
#                 (labels) will be 0 (for negative) and 1 (for positive).  The
#                 feature IDs representing the variables specified each have
#                 value 2 higher than the index of the variable they
#                 represent.

die "usage: conjunction_generator.pl <variables> <var1> [<var2> [...]]\n"
  unless @ARGV > 1;
$variables = $ARGV[0];

for $i (1 .. $variables)
{ push @variable, 0; }

do
{
  for ($i = 1; $i < @ARGV && $variable[$ARGV[$i]]; $i++) { }
  if ($i < @ARGV) { $example = "0"; }
  else { $example = "1"; }

  for ($i = 0; $i < @variable; $i++)
  { if ($variable[$i]) { $example .= ", " . ($i + 2); } }
  print "$example:\n";
} while (test() && increment());

sub test
{
  for ($i = 0; $i < @variable && $variable[$i]; $i++) { }
  return $i < @variable;
}

sub increment
{
  for ($i = 0, $add = 1; $i < @variable && $add; $i++)
  {
    $variable[$i] += $add;
    $add = int($variable[$i] / 2);
    $variable[$i] %= 2;
  }

  return 1;
}