AI::Categorizer restore problem

[PerlDiscuss - Perl Newsgroups and mailing lists]

Hi folks,

I'm trying to implement AI:Categorizer. Everything works fine
until I try to save and restore the state of the learner.

From the synopsis...

my $nb = new
AI::Categorizer::Learner::NaiveBayes(...parameters...);
$nb->train(knowledge_set => $k);
$nb->save_state ('filename');

--- later ----

$nb =
AI::Categorizer::Learner::NaiveBayes->restore_state('filename');
my $c = new AI::Categorizer::Collection::Files( path => ... );
while (my $document = $c->next) {
my $hypothesis = $nb->categorize($document);
print "Best assigned category: ",
$hypothesis->best_category, "\n";
print "All assigned categories: ", join(', ',
$hypothesis->categories), "\n";

However when the line
my $hypothesis = $nb->categorize($document);
is executed I get the following error.

Can't locate object method "predict" via package
"Algorithm::NaiveBayes::Model::Frequency"
at /usr/lib/perl5/site_perl/5.8.3/AI/Categorizer/Learner/NaiveBayes.pm
line 28.

It seems like inheritance is lost between save and restore
states. Any ideas?

Thanks in advance.

PS: CC to email highly appreciated.

[Ken Williams]

Hi PerlDiscuss - Perl Newsgroups and mailing lists,

It's not really inheritance that's lost, it's the actual module code.
You should be able to solve this by just adding a 'use
Algorithm::NaiveBayes::Model::Frequency;' to the second script.

Or if you don't want to hard-code that, you can do:

$nb = AI::Categorizer::Learner::NaiveBayes->restore_state('filename');

eval( 'use ' . ref($nb) );

To solve this correctly, I think I'd have to add this to the
restore_state() method in the NaiveBayes learner class.

-Ken

On Aug 31, 2004, at 6:12 AM, PerlDiscuss - Perl Newsgroups and mailing

[gregg...@gmail.com]

I know this is going to turn out to be a stupid question, but could
someone tell me the easiest way to store and retrieve the state of
the entire AI::Genetic colony, and parameters, to a disk file so it
can be read in and out at will?

I'm doing some constrained optimization experiments that can take
several days, even a week, to run in the background, but I have a
computer (Mac OS X 10.4.8) that is shared, and I need to install
software and restart it almost daily.

I would like to save the entire thing about every hour, but I can
handle the timing part myself.

Sincerely,

Gregg Allen
Cerebra, Inc.

[Brad Larsen]

One (possibly stupid) suggestion is to look at Data::Dumper. It should
work, but may be very slow if the object in question is large. Let us
know if you find anything better.

Cheers,
Brad Larsen

[Benjamin Tucker]

I don't actually have any experience with AI::Genetic, but
Storable.pm is probably your best bet. Take a look at how
AI::Categorizer interfaces with it:
http://search.cpan.org/src/KWILLIAMS/AI-Categorizer-0.07/lib/AI/
Categorizer/Storable.pm

If you throw something like this into the bottom of one of your perl
files, you should be able just to call
$gen->store_state('filename') and then $gen->restore_state
('filename') (where $gen is an instance of AI::Genetic)

package AI::Genetic;

use strict;
use Storable;
use File::Spec ();
use File::Path ();

sub save_state {
my ($self, $path) = @_;
if (-e $path) {
File::Path::rmtree($path) or die "Couldn't overwrite $path: $!";
}
mkdir($path, 0777) or die "Can't create $path: $!";
Storable::nstore($self, File::Spec->catfile($path, 'self'));
}

sub restore_state {
my ($package, $path) = @_;
return Storable::retrieve(File::Spec->catfile($path, 'self'));
}

1;

Ben

[Ala Qumsieh]

--- Benjamin Tucker <b...@greenriver.org> wrote:

> I don't actually have any experience with
> AI::Genetic, but
> Storable.pm is probably your best bet. Take a look
> at how
> AI::Categorizer interfaces with it:
>
http://search.cpan.org/src/KWILLIAMS/AI-Categorizer-0.07/lib/AI/
>
> Categorizer/Storable.pm
>
> If you throw something like this into the bottom of
> one of your perl
> files, you should be able just to call
> $gen->store_state('filename') and then
> $gen->restore_state
> ('filename') (where $gen is an instance of
> AI::Genetic)

[snip code]

Thanks. That's an excellent suggestion. I'll add that
to AI::Genetic and upload a new version soon.

Thanks,
--Ala

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[Gregg Allen]

Awesome! That helped a lot. I'm looking forward to your new and
improved module.

Thanks for creating that module, in the first place, also. When I
first discovered the module about a year ago, I ran about a dozen
random optimization problems from my graduate level operations
research textbook from 25 years ago.

I didn't find a single one it couldn't solve in less than a few
minutes. (Mere seconds in most cases.)

Thanks!

Gregg Allen
Cerebra, Inc.