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##########################################################
# AI::NNFlex::Dataset
##########################################################
# Dataset methods for AI::NNFlex - perform learning etc
# on groups of data
#
##########################################################
# Versions
# ========
#
# 1.0	20050115	CColbourn	New module
#
# 1.1	20050324	CColbourn	Added load support
#
##########################################################
# ToDo
# ----
#
#
###########################################################
#
use strict;
package AI::NNFlex::Dataset;


###########################################################
# AI::NNFlex::Dataset::new
###########################################################
sub new
{
	my $class = shift;
	my $params = shift;
	my $dataset;
	if ($class =~ /HASH/)
	{
		$dataset = $class;
		$dataset->{'data'} = $params;
		return 1;
	}

	my %attributes;
	$attributes{'data'} = $params;

	$dataset = \%attributes;
	bless $dataset,$class;
	return $dataset;
}


###########################################################
# AI::NNFlex::Datasets::run
###########################################################
sub run
{
	my $self = shift;
	my $network = shift;
	my @outputs;
	my $counter=0;

	for (my $itemCounter=0;$itemCounter<(scalar @{$self->{'data'}});$itemCounter +=2)
	{
		$network->run(@{$self->{'data'}}[$itemCounter]);
		$outputs[$counter] = $network->output();
		$counter++;
	}

	return \@outputs;

}

###############################################################
# AI::NNFlex::Dataset::learn
###############################################################
sub learn
{
	my $self = shift;
	my $network = shift;
	my $error;

	for (my $itemCounter=0;$itemCounter<(scalar @{$self->{'data'}});$itemCounter +=2)
	{
		$network->run(@{$self->{'data'}}[$itemCounter]);
		$error += $network->learn(@{$self->{'data'}}[$itemCounter+1]);
	}

	$error = $error*$error;

	return $error;
}

#################################################################
# AI::NNFlex::Dataset::save
#################################################################
# save a dataset in an snns .pat file
#################################################################
sub save
{
	my $dataset = shift;
	my %config = @_;

	open (OFILE,">".$config{'filename'}) or return "File error $!";

	print OFILE "No. of patterns : ".((scalar @{$dataset->{'data'}})/2)."\n";
	print OFILE "No. of input units : ".(scalar @{$dataset->{'data'}->[0]})."\n";
	print OFILE "No. of output units : ".(scalar @{$dataset->{'data'}->[1]})."\n\n";

	my $counter = 1;
	my @values = @{$dataset->{'data'}};
	while (@values)
	{
		print OFILE "# Input pattern $counter:\n";
		my $input = shift (@values); 
		my @array = join " ",@$input;
		print OFILE @array;
		print OFILE "\n";

		print OFILE "# Output pattern $counter:\n";
		my $output = shift(@values); 
		@array = join " ",@$output;
		print OFILE @array;
		print OFILE "\n";

		$counter++;
	}

	close OFILE;
	return 1;
}


#############################################################
# AI::NNFlex::Dataset::load
#############################################################
sub load
{
	my $dataset = shift;
	my %params = @_;

	my @data;

	my $filename = $params{'filename'};
	if (!$filename)
	{
		return "No filename specified";
	}

	open (IFILE,"$filename") or return "Unable to load $filename - $!";

	my %config;
	# snns pat files have a 3 line header, defining number of patterns &
	# number of input and output units
	my $counter =0;
	while ($counter <3)
	{
		my $line = <IFILE>;
		if ($line =~/^\n/ || $line =~/^#/){next}
		my ($tag,$value) = split/:/,$line;
		$tag=lc($tag);
		$tag =~s/ //g;
		
		$config{lc($tag)} = $value;
		$counter++;
	}

	my $filecontent;
	while (<IFILE>)
	{
		if($_ =~ /^#/ || $_ =~ /^\n/){next}
		$filecontent .= $_;
	}

	my @individualvals = split /\s+/s,$filecontent;

	for (my $offset=0;$offset<(scalar @individualvals);$offset+=($config{'no.ofinputunits'} + $config{'no.ofoutputunits'}))
	{
		my @input=@individualvals[$offset..($offset+$config{'no.ofinputunits'}-1)];
		push @data,\@input;
		if ($config{'no.ofoutputunits'} > 0)
		{
			my @output=@individualvals[($offset+$config{'no.ofinputunits'})..($offset+$config{'no.ofinputunits'}+$config{'no.ofoutputunits'}-1)];
			push @data,\@output;
		}
	}

		
	$dataset->new(\@data);

	return 1;
}
	
##########################################################
# AI::NNFlex::Dataset::add
##########################################################
# add an input/output pair to the dataset
##########################################################
sub add
{
	my $dataset= shift;
	my $params = shift;

	if (!$params){return "Nothing to add"};
	if ($params !~/ARRAY/){return "Need a reference to an array"}

	# support adding single patterns (for Hopfield type nets)
	if ($$params[0] !~ /ARRAY/)
	{
		push @{$dataset->{'data'}},$params;
	}
	else
	{
		push @{$dataset->{'data'}},$$params[0];
		push @{$dataset->{'data'}},$$params[1];
	}

	return 1;
}

##################################################################
# AI::NNFlex::Dataset::delete
##################################################################
# delete an item from the dataset by index
##################################################################
sub delete
{
	my $dataset = shift;
	my $index = shift;
	my @indexarray;

	if (!$index){return 0}

	if ($index =~ /ARRAY/)
	{
		@indexarray = @$index;
	}
	else
	{
		$indexarray[0] = $index;
	}

	my @newarray;
	my $counter=0;
	foreach (@indexarray)
	{
		unless ($counter == $_)
		{
			push @newarray,${$dataset->{'data'}}[$_];
		}
	}

	$dataset->{'data'} = \@newarray;

	return 1;
}



1;
=pod

=head1 NAME

AI::NNFlex::Dataset - support for creating/loading/saving datasets for NNFlex nets

=head1 SYNOPSIS

 use AI::NNFlex::Dataset;

 my $dataset = AI::NNFlex::Dataset->new([[0,1,1,0],[0,0,1,1]]);

 $dataset->add([[0,1,0,1],[1,1,0,0]]);

 $dataset->add([0,1,0,0]);

 $dataset->save(filename=>'test.pat');

 $dataset->load(filename=>'test.pat');

=head1 DESCRIPTION

This module allows you to construct, load, save and maintain datasets for use with neural nets implemented using the AI::NNFlex classes. The dataset consists of an array of references to arrays of data. Items may be added in pairs (useful for feedfor...

=head1 CONSTRUCTOR 

=head2 AI::NNFlex::Dataset->new([[INPUT],[TARGET]]);

Parameters:

The constructor takes an (optional) reference to an array of one or more arrays. For convenience you can specify two values at a time (for INPUT and OUTPUT values) or a single value at a time. You can also leave the parameters blank, in which case th...

The return value is an AI::NNFlex::Dataset object.

=head1 METHODS

This is a short list of the main methods implemented in AI::NNFlex::Dataset


=head2 add

 Syntax:

 $dataset->add([[INPUT],[OUTPUT]]);

or

 $dataset->add([VALUE]);

This method adds new values to the end of the dataset. You can specify the values as pairs or individually.

=head2 load

 Syntax:

 $dataset->load(filename=>'filename.pat');

Loads an SNNS type .pat file into a blank dataset. If called on an existing dataset IT WILL OVERWRITE IT!

=head2 save

 $dataset->save(filename=>'filename.pat');

Save the existing dataset as an SNNS .pat file. If the file already exists it will be overwritten.

=head2 delete

 $dataset->delete(INDEX);

or

 $dataset->delete([ARRAY OF INDICES]);

Deletes 1 or more items from the dataset by their index (counting from 0). Note that if you are using pairs of values (in a backprop net for example) you MUST delete in pairs - otherwise you will delete only the input/target, and the indices will be ...

=head1 EXAMPLES

See the code in ./examples.


=head1 PREREQs

None.

=head1 SEE ALSO

 AI::NNFlex


=head1 TODO

Method to delete existing dataset entries by index

Method to validate linear separability of a dataset.

=head1 CHANGES


=head1 COPYRIGHT

Copyright (c) 2004-2005 Charles Colbourn. All rights reserved. This program is free software; you can redistribute it and/or modify 
it under the same terms as Perl itself.

=head1 CONTACT

 charlesc@nnflex.g0n.net



=cut