rainbow-stats.pl

贝叶斯学习算法分类文本。基于朴素贝叶斯分类器的文本分类的通用算法

#!/usr/bin/perl
# The above line is modified by ./Makefile to match the system's
# installed location for Perl.

# Script to process the output from Andrew's rainbow program and produce
# useful summaries of the results. Feed the results intot stdin and 
# all the summaries will arrive on stdout

# If you pass the `-s' command line argument, print only the accuracy
# average and standard deviation.

# setup some default values
$total_accuracy = 0.0;

# When this is zero, only print accuracy average and std.dev.
$verbosity = 1;

# Prune this regex from the end of classnames.
$prune_from_classname = "";

if ($#ARGV >= 0 && $ARGV[0] eq "-s") {
    $verbosity = 0;
    shift;
}

if ($#ARGV >= 0 && $ARGV[0] eq "-p") {
    $prune_from_classname = $ARGV[1];
    printf "Pruning `%s' from classnames\n", $prune_from_classname;
    shift; shift;
}

# Read in the first #
$line = <>;

$trial = 0;
while (&read_trial() != 0) {

    # OK - Lets start with accuracy
    &calculate_accuracy();

    # Now, how about a confusion matrix.
    &confusion();

    $trial++;

}

# Maybe some summary?
# We've had $trial trials

&overall_accuracy();

exit;

# Function to read in the results for one trial into three arrays - @ids, 
# @actual_classifications and @predicted_classifications
# What is the English description of these?
# @ids - 
# @actual_classifications - 
# @predicted_classifications - 
sub read_trial {
    
    undef @ids;
    undef @actual_classifications;
    undef @predicted_classifications;
    undef %classes_to_codes;
    undef @codes_to_classes;

    while (($line = <>) && ($line !~ /^\#[0-9]+$/)) {
	
	chop $line;

	@line = split(' ', $line);

	# Remove the filename from @line and append it to @ids
	push(@ids, shift @line);

	if (length ($prune_from_classname) > 0) {
	    # Remove $prune_from_classname from end of the actual classname
	    #printf ("Before: %s  ", $line[0]);
	    $pruning_regex = sprintf ("^(.+)%s\$", $prune_from_classname);
	    $line[0] =~ s,$pruning_regex,\1,;
	    #printf ("After: %s\n", $line[0]);

	    # Remove $prune_from_classname from end of the predicted classnames
	    $pruning_regex = 
		sprintf ("^(.+)%s(:[\.0-9e+\-]+)\$", $prune_from_classname);
	    for ($i = 1; $i < @line; $i++) {
	        #printf ("Before: %s  ", $line[$i]);
		$line[$i] =~ s,$pruning_regex,\1\2,;
	        #printf ("After: %s\n", $line[$i]);
	    }
	}

	# Ensure we have a code for the actual class
	if (grep(/^$line[0]$/, @codes_to_classes) == 0) {
	    $classes_to_codes{$line[0]} = @codes_to_classes;
	    push(@codes_to_classes, $line[0]);
	}

	push(@actual_classifications, shift @line);
			    
	push(@predicted_classifications, [ @line ]);

	# Make sure we have codes for everything
	foreach $pred (@line) {
	    $pred =~ /^(.+):[\.0-9e+\-]+$/;

	    if (grep(/^$1$/, @codes_to_classes) == 0) {
		$classes_to_codes{$1} = @codes_to_classes;
		push(@codes_to_classes, $1);
	    }
	}
    }

    if (@ids > 0) {
	return 1;
    } else {
	return 0;
    }
}

# Function to take the three arrays and calculate the accuracy of the
# run
sub calculate_accuracy {
    if ($verbosity > 0) {
	print "Trial $trial\n\n";
    }
    # Initialize the variables in which we'll gather stats
    $correct = 0;
    $total = 0;

    for ($i = 0; $i < @ids; $i++) {
	$predicted_classifications[$i][0] =~ /^(.+):[\.0-9e+\-]+$/;
	if ($actual_classifications[$i] eq $1) {
	    $correct++;
	}
	$total++;
    }

    $accuracy = ($correct * 100) / $total;
    $trial_accuracy[$trial] = $accuracy;
    $total_accuracy += $accuracy;
    if ($verbosity > 0) {
	printf ("Correct: %d out of %d (%.2f percent accuracy)\n",
		$correct, $total, $accuracy);
    }
}

sub overall_accuracy {
    # Calculte the overall (overall) accuracy
    $overall_accuracy = $total_accuracy / $trial;

    # Calculate the standard deviation of Overall Accuracy
    $overall_accuracy_stddev = 0;
    for ($i = 0; $i < $trial; $i++) {
	$diff_from_mean = $overall_accuracy - $trial_accuracy[$i];
	$overall_accuracy_stddev += $diff_from_mean * $diff_from_mean;
    }
    $overall_accuracy_stddev = sqrt ($overall_accuracy_stddev / $trial);

    if ($verbosity > 0) {
	printf ("Percent_Accuracy  average %.2f stderr %.2f\n", 
		$overall_accuracy, 
		$overall_accuracy_stddev / sqrt($trial));
    } else {
	printf ("%.2f %.2f\n", 
		$overall_accuracy, 
		$overall_accuracy_stddev / sqrt($trial));
    }
}

# Function to produce a confusion matrix from the data
sub confusion {
    
    undef @confusion;
    my $total_predicted;

    if (! $verbosity > 0) {
	return;
    }

    print "\n - Confusion details, row is actual, column is predicted\n";
    # Loop over all the examples
    for ($i = 0; $i < @ids; $i++) {

	$actual = $actual_classifications[$i];
	$actual_code = $classes_to_codes{$actual};

	$predicted_classifications[$i][0] =~ /^(.+):[\.0-9e+\-]+$/;
	$predicted_code = $classes_to_codes{$1};

	$confusion[$actual_code][$predicted_code] += 1;
    }

    # Get the maximum classname length, so we know how much space
    # to allow for it in the formatting.
    $max_classname_length = length ("classname");
    for ($i = 0; $i < @codes_to_classes; $i++) {
	$classname_length = length ($codes_to_classes[$i]);
	if ($classname_length > $max_classname_length) {
	    $max_classname_length = $classname_length;
	}
    }

    # Print out a header for the matrix
    printf ("   %${max_classname_length}s ", "classname");
    for ($i = 0; $i < @codes_to_classes; $i++) {
	printf ("%3d ", $i);	
    }
    print " :total\n";

    # Now print out the matrix
    for ($i = 0; $i < @codes_to_classes; $i++) {
	printf ("%2d %${max_classname_length}s ", 
		$i, $codes_to_classes[$i]);
	$total_predicted = 0;

	for ($j = 0; $j < @codes_to_classes; $j++) {
	    if ($confusion[$i][$j] == 0) {
		printf ("%3s ", ".");
	    } else {
		printf ("%3d ", $confusion[$i][$j]);
	    }
	    $total_predicted += $confusion[$i][$j];
	}
	if ($total_predicted > 0) {
	    printf (" :%3d %6.2f%%", 
		    $total_predicted, 
		    100 * $confusion[$i][$i] / $total_predicted);
	} else {
	    printf (" :%3s", ".");
	}
	print "\n";
    }
    print "\n";
}