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package AI::PBDD;

use strict;
use vars qw(@ISA @EXPORT @EXPORT_OK %EXPORT_TAGS $VERSION);

require Exporter;
require DynaLoader;

use constant BDD_REORDER_NONE => 0;
use constant BDD_REORDER_WIN2 => 1;
use constant BDD_REORDER_WIN3 => 2;
use constant BDD_REORDER_SIFT => 3;
use constant BDD_REORDER_RANDOM => 4;


@ISA = qw(Exporter DynaLoader);

@EXPORT = qw(
	      BDD_REORDER_NONE
	      BDD_REORDER_WIN2
	      BDD_REORDER_WIN3
	      BDD_REORDER_SIFT
	      BDD_REORDER_RANDOM
);

@EXPORT_OK = qw(
// setup and cleanup
		 init
		 gc
		 verbose
		 kill
// simple BDD operations
		 getOne
		 getZero
		 createBDD
		 getVarCount
		 getBDD
// ref counting
		 ref
		 deref
		 localDeref
// BDD operations
		 and
		 or
		 andTo
		 orTo
		 nand
		 nor
		 xor
		 ite
		 imp
		 biimp
		 not
                 makeSet
		 exists
		 forall
		 relProd
		 restrict
		 constrain
// variables replacement
		 createPair
		 deletePair
		 replace
		 showPair
// BDD analysis
		 support
		 nodeCount
		 satOne
		 satCount
// printing
		 printDot
		 printSet
		 print
// debugging
		 printStats                 
		 checkPackage
		 debugPackage
		 debugBDD
// low-level access
		 internal_index
		 internal_refcount
		 internal_isconst
		 internal_constvalue
		 internal_iscomplemented
		 internal_then
		 internal_else
// dynamic variable ordering
		 reorder_setMethod
		 reorder_now
		 reorder_enableDynamic
		 reorder_createVariableGroup
);

$VERSION = '0.01';

bootstrap AI::PBDD $VERSION;

sub satCount {
  my ($bdd, $vars_ignored) = @_;

  if (!defined($vars_ignored)) {
    return satCount__I($bdd);
  } else {
    return satCount__II($bdd, $vars_ignored);
  }
}

sub printDot {
  my ($bdd, $filename) = @_;

  if (!defined($filename)) {
      printDot__I($bdd);
  } else {
      printDot__II($bdd, $filename);
  }
}

sub makeSet {
  my ($vars, $size, $offset) = @_;

  if (!defined($offset)) {
      return makeSetI($vars, $size);
  } else {
      return makeSetII($vars, $size, $offset);
  }
}

sub createPair {
  my ($old, $new) = @_;
  my $size = @$old;

  return createPairI($old, $new, $size);
}

1;

__END__

=head1 AI::PBDD

Perl wrapper for the BuDDy C library

=head1 SYNOPSIS

  use AI::PBDD qw(init createBDD and printDot kill);

  init(100, 100000);

  my $var1 = createBDD();
  my $var2 = createBDD();

  my $bdd = and($var1, $var2);

  printDot($bdd);

  kill();

=head1 DESCRIPTION

Binary Decision Diagrams (BDDs) are used for efficient computation of many common problems. This is done by giving a compact representation and a set of efficient operations on boolean functions f: {0,1}^n --> {0,1}.

It turns out that this representation is good enough to solve a huge amount of problems in Artificial Intelligence and other areas of computing such as hardware verification.

This is a Perl interface to the popular BDD package BuDDy. The interface is largely inspired by JBDD, a Java common interface for the two BDD packages BuDDy and CUDD written by Arash Vahidi, which can be found at L<http://javaddlib.sourceforge.net/jb...

PBDD allows you to combine the power of Perl with an efficient BDD package written in highly optimized C.

=head1 FUNCTIONS

=head2 SETUP AND CLEANUP

=over 4 

=item B<init($nvars, $nnodes))>

Initialize the BDD package using the given number of variables and nodes.

=item B<gc>

Invoke garbage collection.

=item B<verbose($be_verbose)>

Make the BDD package verbose or non-verbose.

=item B<kill>

Close the BDD package and cleanup.

=back

=head2 SIMPLE BDD OPERATIONS

=over 4

=item B<$bddone = getOne>

Returns the BDD constant 1.

=item B<$bddzero = getZero>

Returns the BDD constant 0.

=item B<$bdd = createBDD>

Returns a new BDD variable.

=item B<$nvars = getVarCount>

Returns the number of BDD variables currently in the system.

=item B<$bdd = getBDD($idx)>

Returns the BDD at the given index C<$idx> (ranked after calling C<createBDD>).

=back

lib/AI/PBDD.pm  view on Meta::CPAN

Get the ELSE-node of a BDD.

=back

=head2 DYNAMIC VARIABLE ORDERING

=over 4

=item B<reorder_setMethod($method)>

Set dynamic reordering heuristic. The possible values are:

=over 4

=item BDD_REORDER_NONE

No reordering.

=item BDD_REORDER_WIN2

Reordering using a sliding window of size 2. This algorithm swaps two adjacent variable blocks and if this results in more nodes then the two blocks are swapped back again. Otherwise the result is kept in the variable order. This is then repeated for...

=item BDD_REORDER_WIN3

Same as above but with a window size of 3.

=item BDD_REORDER_SIFT

Each block is moved through all possible positions. The best of these is then used as the new position. Potentially a very slow but good method.

=item BDD_REORDER_RANDOM

Select a random position for each variable.

=back

These constants are automatically exported by the package.

=item B<reorder_now>

Start dynamic reordering.

=item B<reorder_enableDynamic($enable)>

Enable/disable automatic dynamic reordering.

=item B<reorder_createVariableGroup($first,$last,$fix_group)>

Create a variable block, between the C<$first> and C<$last> variable indexes. Parameter C<$fix_group> decides whether to allow reordering inside the group or fix to current ordering.

=back

=head1 SEE ALSO

BDDs and their operations are described in many academic papers that can be found on the Internet. A good place to get started with BDDs is the wikipedia article L<http://en.wikipedia.org/wiki/Binary_decision_diagram>.

It can also be useful to look at the test code for this package in the C<t> directory, as well as at the JBDD documentation and exaples at L<http://javaddlib.sourceforge.net/jbdd/>.

=head1 VERSION
    
This man page documents "PBDD" version 0.01.

=head1 AUTHOR

  Gianluca Torta
  mailto:torta@di.unito.it

=head1 COPYRIGHT

Copyright (c) 2011 by Gianluca Torta. All rights reserved.

=head1 LICENSE

This package is free software; you can use, modify and redistribute
it under the same terms as Perl itself, i.e., at your option, under
the terms either of the "Artistic License" or the "GNU General Public
License".

The interface design and part of the C code and documentation are modifications of the JBDD package by Arash Vahidi. A copy of the JBDD licence can be found in the C<licences> directory of this package.

=head1 DISCLAIMER

This package is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the "GNU General Public License" for more details.

=cut