Bio::Tools::HMMER Results
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Summary
Bio::Tools::HMMER::Results - Object representing HMMER output results
Package variables
No package variables defined.
Included modules
Bio::Root::IO
Bio::Root::Root
Bio::SeqAnalysisParserI
Bio::Tools::HMMER::Domain
Bio::Tools::HMMER::Set
Carp
Symbol
strict
Inherit
Bio::Root::IO Bio::Root::Root Bio::SeqAnalysisParserI
Synopsis
   # parse a hmmsearch file (can also parse a hmmpfam file)
$res = new Bio::Tools::HMMER::Results( -file => 'output.hmm' , -type => 'hmmsearch');
# print out the results for each sequence foreach $seq ( $res->each_Set ) { print "Sequence bit score is",$seq->bits,"\n"; foreach $domain ( $seq->each_Domain ) { print " Domain start ",$domain->start," end ",$domain->end, " score ",$domain->bits,"\n"; } } # new result object on a sequence/domain cutoff of 25 bits sequence, 15 bits domain $newresult = $res->filter_on_cutoff(25,15); # alternative way of getting out all domains directly foreach $domain ( $res->each_Domain ) { print "Domain on ",$domain->seq_id," with score ", $domain->bits," evalue ",$domain->evalue,"\n"; }
Description
This object represents HMMER output, either from hmmsearch or
hmmpfam. For hmmsearch, a series of HMMER::Set objects are made, one
for each sequence, which have the the bits score for the object. For
hmmpfam searches, only one Set object is made.
These objects come from the original HMMResults modules used
internally in Pfam, written by Ewan. Ewan then converted them to
bioperl objects in 1999. That conversion is meant to be backwardly
compatible, but may not be (caveat emptor).
Methods
_parse_hmmpfamDescriptionCode
_parse_hmmsearchDescriptionCode
add_DomainDescriptionCode
add_SetDescriptionCode
dictate_hmm_acc
No description
Code
domain_bits_cutoff_from_evalueDescriptionCode
each_DomainDescriptionCode
each_SetDescriptionCode
filter_on_cutoffDescriptionCode
get_SetDescriptionCode
get_unit_nse
No description
Code
highest_noise
No description
Code
hmmfileDescriptionCode
lowest_true
No description
Code
new
No description
Code
next_featureDescriptionCode
numberDescriptionCode
parsetypeDescriptionCode
seqfileDescriptionCode
write_FT_outputDescriptionCode
write_GDF
No description
Code
write_GDF_bitsDescriptionCode
write_ascii_outDescriptionCode
write_scores_bits
No description
Code
Methods description
_parse_hmmpfamcode    nextTop
 Title   : _parse_hmmpfam
Usage : $res->_parse_hmmpfam($filehandle)
Function:
Returns :
Args :
_parse_hmmsearchcodeprevnextTop
 Title   : _parse_hmmsearch
Usage : $res->_parse_hmmsearch($filehandle)
Function:
Returns :
Args :
add_DomaincodeprevnextTop
 Title   : add_Domain
Usage : $res->add_Domain($unit)
Function: adds a domain to the results array. Mainly used internally.
Args : A Bio::Tools::HMMER::Domain
add_SetcodeprevnextTop
 Title   : add_Set
Usage : Mainly internal function
Function:
Returns :
Args :
domain_bits_cutoff_from_evaluecodeprevnextTop
 Title   : domain_bits_cutoff_from_evalue
Usage : $cutoff = domain_bits_cutoff_from_evalue(0.01);
Function: return a bits cutoff from an evalue using the
scores here. Somewhat interesting logic:
Find the two bit score which straddle the evalue
if( 25 is between these two points) return 25
else return the midpoint.
This logic tries to ensure that with large signal to noise separation one still has sensible 25 bit cutoff Returns : Args :
each_DomaincodeprevnextTop
 Title   : each_Domain
Usage : foreach $domain ( $res->each_Domain() )
Function: array of Domain units which are held in this report
Returns : array
Args : none
each_SetcodeprevnextTop
 Title   : each_Set
Usage :
Function:
Returns :
Args :
filter_on_cutoffcodeprevnextTop
 Title   : filter_on_cutoff
Usage : $newresults = $results->filter_on_cutoff(25,15);
Function: Produces a new HMMER::Results module which has
been trimmed at the cutoff.
Returns : a Bio::Tools::HMMER::Results module
Args : sequence cutoff and domain cutoff. in bits score
if you want one cutoff, simply use same number both places
get_SetcodeprevnextTop
 Title   : get_Set
Usage : $set = $res->get_Set('sequence-name');
Function: returns the Set for a particular sequence
Returns : a HMMER::Set object
Args : name of the sequence
hmmfilecodeprevnextTop
 Title   : hmmfile
Usage : $obj->hmmfile($newval)
Function:
Example :
Returns : value of hmmfile
Args : newvalue (optional)
next_featurecodeprevnextTop
 Title   : next_feature
Usage : while( my $feat = $res->next_feature ) { # do something }
Function: SeqAnalysisParserI implementing function
Example :
Returns : A Bio::SeqFeatureI compliant object, in this case,
each DomainUnit object, ie, flattening the Sequence
aspect of this.
Args : None
numbercodeprevnextTop
 Title   : number
Usage : print "There are ",$res->number," domains hit\n";
Function: provides the number of domains in the HMMER report
parsetypecodeprevnextTop
 Title   : parsetype
Usage : $obj->parsetype($newval)
Function:
Returns : value of parsetype
Args : newvalue (optional)
seqfilecodeprevnextTop
 Title   : seqfile
Usage : $obj->seqfile($newval)
Function:
Example :
Returns : value of seqfile
Args : newvalue (optional)
write_FT_outputcodeprevnextTop
 Title   : write_FT_output
Usage : $res->write_FT_output(\*STDOUT,'DOMAIN')
Function: writes feature table output ala swissprot
Returns :
Args :
write_GDF_bitscodeprevnextTop
 Title   : write_GDF_bits
Usage : $res->write_GDF_bits(25,15,\*STDOUT)
Function: writes GDF format with a sequence,domain threshold
Returns :
Args :
write_ascii_outcodeprevnextTop
 Title   : write_ascii_out
Usage : $res->write_ascii_out(\*STDOUT)
Function: writes as
seq seq_start seq_end model-acc model_start model_end model_name
Returns :
Args :
FIXME: Now that we have no modelacc, this is probably a bad thing.
Methods code
_parse_hmmpfamdescriptionprevnextTop
sub _parse_hmmpfam {
    my $self = shift;
    my $file = shift;
    
    my ($id,$sqfrom,$sqto,$hmmf,$hmmt,$sc,$ev,
	$unit,$nd,$seq,$name,$seqname,$from,
	$to,%hash,%acc,$acc);
    my $count = 0;

    while(<$file>) {
        if( /^HMM file:\s+(\S+)/ ) { $self->hmmfile($1); next; }
	elsif( /^Sequence file:\s+(\S+)/ ) { $self->seqfile($1); next }   
	elsif( /^Query(\s+sequence)?:\s+(\S+)/ ) {
	    
	    $seqname = $2;
	    
	    $seq     = Bio::Tools::HMMER::Set->new();

	    $seq ->name($seqname);
	    $self->add_Set($seq);
	    %hash = ();
	    
	    while(<$file>){

		if( /Accession:\s+(\S+)/ ) { $seq->accession($1); next }
		elsif( s/^Description:\s+// ) { chomp; $seq->desc($_); next } 
		/^Parsed for domains/ && last;
		
		# This is to parse out the accession numbers in old Pfam format.
# now not support due to changes in HMMER.
if( (($id,$acc, $sc, $ev, $nd) = /^\s*(\S+)\s+(\S+).+?\s(\S+)\s+(\S+)\s+(\d+)\s*$/)) { $hash{$id} = $sc; # we need this for the sequence
# core of the domains below!
$acc {$id} = $acc; # this is the more common parsing routine
} elsif ( (($id,$sc, $ev, $nd) = /^\s*(\S+).+?\s(\S+)\s+(\S+)\s+(\d+)\s*$/) ) { $hash{$id} = $sc; # we need this for the
# sequence score of hte domains below!
} } while(<$file>) { /^Align/ && last; /^\/\// && last; # this is meant to match
#Sequence Domain seq-f seq-t hmm-f hmm-t score E-value
#-------- ------- ----- ----- ----- ----- ----- -------
#PF00621 1/1 198 372 .. 1 207 [] 281.6 1e-80
if( (($id, $sqfrom, $sqto, $hmmf,$hmmt,$sc, $ev) = /(\S+)\s+\S+\s+(\d+)\s+(\d+).+?(\d+)\s+(\d+)\s+\S+\s+(\S+)\s+(\S+)\s*$/)) { $unit = Bio::Tools::HMMER::Domain->new(); $unit->seq_id ($seqname); $unit->hmmname ($id); $unit->start ($sqfrom); $unit->end ($sqto); $unit->hstart($hmmf); $unit->hend ($hmmt); $unit->bits ($sc); $unit->evalue ($ev); if( !exists($hash{$id}) ) { $self->throw("HMMResults parsing error in hmmpfam for $id - can't find sequecne score"); } $unit->seqbits($hash{$id}); if( defined $acc{$id} ) { $unit->hmmacc($acc{$id}); } # this should find it's own sequence!
$self->add_Domain($unit); } } if( /^\/\// ) { next; } $_ = <$file>; # parses alignment lines. Icky as we have to break on the same line
# that we need to read to place the alignment lines with the unit.
while(1) { (!defined $_ || /^\/\//) && last; # matches:
# PF00621: domain 1 of 1, from 198 to 372
if( /^\s*(\S+):.*from\s+(\d+)\s+to\s+(\d+)/ ) { $name = $1; $from = $2; $to = $3; # find the HMMUnit which this alignment is from
$unit = $self->get_unit_nse($seqname,$name,$from,$to); if( !defined $unit ) { $self->warn("Could not find $name $from $to unit even though I am reading it in. ugh!"); $_ = <$file>; next; } while(<$file>) { /^\/\// && last; /^\s*\S+:.*from\s+\d+\s+to\s+\d+/ && last; $unit->add_alignment_line($_); } } else { $_ = <$file>; } } # back to main 'Query:' loop
} } } # mainly internal function
}
_parse_hmmsearchdescriptionprevnextTop
sub _parse_hmmsearch {
    my $self = shift;
    my $file = shift;
    my ($id,$sqfrom,$sqto,$sc,$ev,$unit,$nd,$seq,$hmmf,$hmmt,
	$hmmfname,$hmmacc, $hmmid, %seqh);
    my $count = 0;
    
    while(<$file>) {
        /^HMM file:\s+(\S+)/ and do { $self->hmmfile($1); $hmmfname = $1 };
	/^Accession:\s+(\S+)/ and do { $hmmacc = $1 };
	/^Query HMM:\s+(\S+)/ and do { $hmmid = $1 };	
	/^Sequence database:\s+(\S+)/ and do { $self->seqfile($1) };
        /^Scores for complete sequences/ && last;
    }
    
    $hmmfname = "given" if not $hmmfname;  
    
    while(<$file>) {
	/^Parsed for domains/ && last;
	if( (($id, $sc, $ev, $nd) = /(\S+).+?\s(\S+)\s+(\S+)\s+(\d+)\s*$/)) {
	    $seq = Bio::Tools::HMMER::Set->new();
	    $seq->name($id);
	    $seq->bits($sc);
	    $seqh{$id} = $sc;
	    $seq->evalue($ev);
	    $self->add_Set($seq);
	    $seq->accession($hmmacc);
	}
    }

    while(<$file>) {
	/^Alignments of top-scoring domains/ && last;
	if( (($id, $sqfrom, $sqto, $hmmf, $hmmt, $sc, $ev) = /(\S+)\s+\S+\s+(\d+)\s+(\d+).+?(\d+)\s+(\d+)\s+\S+\s+(\S+)\s+(\S+)\s*$/)) {
	    $unit = Bio::Tools::HMMER::Domain->new();

	    $unit->seq_id($id);
	    $unit->hmmname($hmmfname);
	    $unit->start($sqfrom);
	    $unit->end($sqto);
	    $unit->bits($sc);
	    $unit->hstart($hmmf);
	    $unit->hend($hmmt);
	    $unit->evalue($ev);
	    $unit->seqbits($seqh{$id});
	    $self->add_Domain($unit);
	    $count++;
	}
    }

    $_ = <$file>;

    ## Recognize and store domain alignments
while(1) { if( !defined $_ ) { last; } /^Histogram of all scores/ && last; # matches:
# PF00621: domain 1 of 1, from 198 to 372
if( /^\s*(\S+):.*from\s+(\d+)\s+to\s+(\d+)/ ) { my $name = $1; my $from = $2; my $to = $3; # find the HMMUnit which this alignment is from
$unit = $self->get_unit_nse($name,$hmmfname,$from,$to); if( !defined $unit ) { $self->warn("Could not find $name $from $to unit even though I am reading it in. ugh!"); next; } while(<$file>) { /^Histogram of all scores/ && last; /^\s*\S+:.*from\s+\d+\s+to\s+\d+/ && last; $unit->add_alignment_line($_); } } else { $_ = <$file>; } } return $count;
}
add_DomaindescriptionprevnextTop
sub add_Domain {
    my $self = shift;
    my $unit = shift;
    my $name;

    $name = $unit->seq_id();

    if( ! exists $self->{'seq'}->{$name} ) {
	$self->warn("Adding a domain of $name but with no HMMSequence. Will be kept in domain array but not added to a HMMSequence");
    } else {
	$self->{'seq'}->{$name}->add_Domain($unit);
    }
    push(@{$self->{'domain'}},$unit);
}
add_SetdescriptionprevnextTop
sub add_Set {
    my $self = shift;
    my $seq  = shift;
    my $name;

    $name = $seq->name();

    if( exists $self->{'seq'}->{$name} ) {
	$self->throw("You alredy have $name in HMMResults!");
    }
    $self->{'seq'}->{$name} = $seq;
}
dictate_hmm_accdescriptionprevnextTop
sub dictate_hmm_acc {
    my $self = shift;
    my $acc = shift;
    my ($unit);

	
    foreach $unit ( $self->eachHMMUnit() ) {
	$unit->hmmacc($acc);
    }
}
domain_bits_cutoff_from_evaluedescriptionprevnextTop
sub domain_bits_cutoff_from_evalue {
    my $self = shift;
    my $eval = shift;
    my ($dom,$prev,@doms,$cutoff,$sep,$seen);

    @doms = $self->each_Domain;


    @doms = map { $_->[0] } 
            sort { $b->[1] <=> $a->[1] } 
            map { [ $_, $_->bits] } @doms;
    $seen = 0;
    foreach $_ ( @doms ) {
	if( $_->evalue > $eval ) {
	    $seen = 1;
	    $dom = $_;
	    last;
	} 
	$prev = $_;
    }
    
    if( ! defined $prev || $seen == 0) {
	$self->throw("Evalue is either above or below the list...");
	return undef;
    }

    $sep = $prev->bits - $dom->bits ;
    
    if( $sep < 1 ) {
	return $prev->bits();
    }
    if( $dom->bits < 25 && $prev->bits > 25 ) {
	return 25;
    }

    return int( $dom->bits + $sep/2 ) ;
}
each_DomaindescriptionprevnextTop
sub each_Domain {
    my $self = shift;
    my (@arr,$u);

    foreach $u ( @{$self->{'domain'}} ) {
	push(@arr,$u);
    }

    return @arr;
}
each_SetdescriptionprevnextTop
sub each_Set {
    my $self = shift;
    my (@array,$name);


    foreach $name ( keys %{$self->{'seq'}} ) {
	push(@array,$self->{'seq'}->{$name});
    }
    return @array;
}
filter_on_cutoffdescriptionprevnextTop
sub filter_on_cutoff {
    my $self = shift;
    my $seqthr = shift;
    my $domthr = shift;
    my ($new,$seq,$unit,@array,@narray);

    if( !defined $domthr ) {
       $self->throw("hmmresults filter on cutoff needs two arguments");
    }

    $new = Bio::Tools::HMMER::Results->new(-type => $self->parsetype);

    foreach $seq ( $self->each_Set()) {
	next if( $seq->bits() < $seqthr );
	$new->add_Set($seq);
	foreach $unit ( $seq->each_Domain() ) {
	    next if( $unit->bits() < $domthr );
	    $new->add_Domain($unit);
	}
    }    
    $new;
}
get_SetdescriptionprevnextTop
sub get_Set {
    my $self = shift;
    my $name = shift;

    return $self->{'seq'}->{$name};
}
get_unit_nsedescriptionprevnextTop
sub get_unit_nse {
    my $self    = shift;
    my $seqname = shift;
    my $domname = shift;
    my $start   = shift;
    my $end     = shift;

    my($seq,$unit);
    
    $seq = $self->get_Set($seqname);

    if( !defined $seq ) {
	$self->throw("Could not get sequence name $seqname - so can't get its unit");
    }

    foreach $unit ( $seq->each_Domain() ) {
	if( $unit->hmmname() eq $domname && $unit->start() == $start &&  $unit->end() == $end ) {
	    return $unit;
	}
    }

    return undef;
}
highest_noisedescriptionprevnextTop
sub highest_noise {
    my $self = shift;
    my $seqt = shift;
    my $domt = shift;
    my ($seq,$unit,$hseq,$hdom,$noiseseq,$noisedom);

    $hseq = $hdom = -100000;
    
    foreach $seq ( $self->eachHMMSequence()) {
	if( $seq->bits() < $seqt && $seq->bits() > $hseq  ) {
	    $hseq = $seq->bits();
	    $noiseseq = $seq;
	}
	foreach $unit ( $seq->eachHMMUnit() ) {
	    if( (($seq->bits() < $seqt) || ($seq->bits() > $seqt && $unit->bits < $domt)) && $unit->bits() > $hdom ) {
		$hdom  = $unit->bits();
		$noisedom = $unit;
	    }
	}
    }


    return ($noiseseq,$noisedom);
}
hmmfiledescriptionprevnextTop
sub hmmfile {
   my ($self,$value) = @_;
   if( defined $value) {
      $self->{'hmmfile'} = $value;
    }
    return $self->{'hmmfile'};
}
lowest_truedescriptionprevnextTop
sub lowest_true {
    my $self = shift;
    my $seqt = shift;
    my $domt = shift;
    my ($seq,$unit,$lowseq,$lowdom,$trueseq,$truedom);

    if( ! defined $domt ) {
	carp "lowest true needs at least a domain threshold cut-off";
	return (0,0);
    }

    $lowseq = $lowdom = 100000;

    foreach $seq ( $self->eachHMMSequence()) {
	
	if( $seq->bits() >= $seqt && $seq->bits() < $lowseq  ) {
	    $lowseq = $seq->bits();
	    $trueseq = $seq;
	}
	if( $seq->bits() < $seqt ) {
	    next;
	}

	foreach $unit ( $seq->eachHMMUnit() ) {
	    if( $unit->bits() >= $domt && $unit->bits() < $lowdom ) {
		$lowdom  = $unit->bits();
		$truedom = $unit;
	    }
	}
    }


    return ($trueseq,$truedom);
}
newdescriptionprevnextTop
sub new {
  my($class,@args) = @_;

  my $self = $class->SUPER::new(@args);

  $self->{'domain'} = []; # array of HMMUnits
$self->{'seq'} = {}; my ($parsetype) = $self->_rearrange([qw(TYPE)],@args); $self->_initialize_io(@args); if( !defined $parsetype ) { $self->throw("No parse type provided. should be hmmsearch or hmmpfam"); } $self->parsetype($parsetype); if( defined $self->_fh() ) { if( $parsetype eq 'hmmsearch' ) { $self->_parse_hmmsearch($self->_fh()); } elsif ( $parsetype eq 'hmmpfam' ) { $self->_parse_hmmpfam($self->_fh()); } else { $self->throw("Did not recoginise type $parsetype"); } } return $self; # success - we hope!
}
next_featuredescriptionprevnextTop
sub next_feature {
   my ($self) = @_;

   if( $self->{'_started_next_feature'} == 1 ) {
       return shift @{$self->{'_next_feature_array'}};
   } else {
       $self->{'_started_next_feature'} = 1;
       my @array;
       foreach my $seq ( $self->each_Set() ) {
	   foreach my $unit ( $seq->each_Domain() ) {
	       push(@array,$unit);
	   }
       }
       my $res = shift @array;
       $self->{'_next_feature_array'} =\@ array;
       return $res;
   }
   
   $self->throw("Should not reach here! Error!");
}
numberdescriptionprevnextTop
sub number {
    my $self = shift;
    my @val;
    my $ref;
    $ref = $self->{'domain'};

   
    @val = @{$self->{'domain'}};
    return scalar @val;
}
parsetypedescriptionprevnextTop
sub parsetype {
   my ($self,$value) = @_;
   if( defined $value) {
      $self->{'_parsetype'} = $value;
    }
    return $self->{'_parsetype'};
}

1;  # says use was ok
__END__
}
seqfiledescriptionprevnextTop
sub seqfile {
   my ($self,$value) = @_;
   if( defined $value) {
      $self->{'seqfile'} = $value;
    }
    return $self->{'seqfile'};
}
write_FT_outputdescriptionprevnextTop
sub write_FT_output {
    my $self = shift;
    my $file = shift;
    my $idt  = shift;
    my ($seq,$unit);

    if( !defined $idt ) {
	$idt = "DOMAIN";
    }

    foreach $seq ( $self->each_Set() ) {
	print $file sprintf("ID   %s\n",$seq->name());
	foreach $unit ( $seq->each_Domain() ) {
	    print $file sprintf("FT   %s   %d %d %s\n",$idt,
				$unit->start,$unit->end,$unit->hmmname);
	}
	print $file "//\n";
    }
}
write_GDFdescriptionprevnextTop
sub write_GDF {
    my $self = shift;
    my $file = shift;
    my $unit;

    if( !defined $file ) {
	$file =\* STDOUT;
    }


    foreach $unit ( $self->eachHMMUnit() ) {
	print $file sprintf("%-24s\t%6d\t%6d\t%15s\t%.1f\t%g\n",$unit->get_nse(),$unit->start(),$unit->end(),$unit->seq_id(),$unit->bits(),$unit->evalue);
    }
}
write_GDF_bitsdescriptionprevnextTop
sub write_GDF_bits {
    my $self = shift;
    my $seqt = shift;
    my $domt = shift;
    my $file = shift;
    my $seq;
    my $unit;
    my (@array,@narray);

    if( !defined $file ) {
	$self->throw("Attempting to use write_GDF_bits without passing in correct arguments!");
	return;
    }

    foreach $seq ( $self->each_Set()) {

	if( $seq->bits() < $seqt ) {
	    next;
	}

	foreach $unit ( $seq->each_Domain() ) {
	    if( $unit->bits() < $domt ) {
		next;
	    }
	    push(@array,$unit);
	}

    }

    @narray = sort { my ($aa,$bb,$st_a,$st_b); 
		     $aa = $a->seq_id(); 
		     $bb = $b->seq_id(); 
		     if ( $aa eq $bb) {
			 $st_a = $a->start();
			 $st_b = $b->start();
			 return $st_a <=> $st_b;
			 } 
		     else {
			 return $aa cmp $bb; 
		     } } @array;

    foreach $unit ( @narray ) {
	print $file sprintf("%-24s\t%6d\t%6d\t%15s\t%.1f\t%g\n",$unit->get_nse(),$unit->start(),$unit->end(),$unit->seq_id(),$unit->bits(),$unit->evalue);
    }
}
write_ascii_outdescriptionprevnextTop
sub write_ascii_out {
    my $self = shift;
    my $fh = shift;
    my ($unit,$seq);

    if( !defined $fh) {
	$fh =\* STDOUT;
    }


    foreach $seq ( $self->each_Set()) {
	foreach $unit ( $seq->each_Domain()) {
	    print $fh sprintf("%s %4d %4d %s %4d %4d %4.2f %4.2g %s\n",
			      $unit->seq_id(),$unit->start(),$unit->end(),
			      $unit->hmmacc,$unit->hstart,$unit->hend,
			      $unit->bits,$unit->evalue,$unit->hmmname);
	}
    }
}
write_scores_bitsdescriptionprevnextTop
sub write_scores_bits {
    my $self = shift;
    my $seqt = shift;
    my $domt = shift;
    my $file = shift;
    my $seq;
    my $unit;
    my (@array,@narray);

    if( !defined $file ) {
	carp("Attempting to use write_scores_bits without passing in correct arguments!");
	return;
    }

    foreach $seq ( $self->eachHMMSequence()) {

	if( $seq->bits() < $seqt ) {
	    next;
	}

	foreach $unit ( $seq->eachHMMUnit() ) {
	    if( $unit->bits() < $domt ) {
		next;
	    }
	    push(@array,$unit);
	}

    }

    @narray = sort { my ($aa,$bb,$st_a,$st_b); 
		     $aa = $a->bits(); 
		     $bb = $b->bits(); 
		     return $aa <=> $bb; 
		     } @array;

    foreach $unit ( @narray ) {
	print $file sprintf("%4.2f %s\n",$unit->bits(),$unit->get_nse());
    }
}
General documentation
FEEDBACKTop
Mailing ListsTop
User feedback is an integral part of the evolution of this and other
Bioperl modules. Send your comments and suggestions preferably to one
of the Bioperl mailing lists. Your participation is much appreciated.
  bioperl-l@bioperl.org                - General discussion
http://www.bioperl.org/MailList.html - About the mailing lists
Reporting BugsTop
Report bugs to the Bioperl bug tracking system to help us keep track
the bugs and their resolution. Bug reports can be submitted via email
or the web:
  bioperl-bugs@bio.perl.org
http://www.bugzilla.bioperl.org/
AUTHOR - Ewan BirneyTop
Email birney@ebi.ac.uk
CONTRIBUTORSTop
Jason Stajich, jason@bioperl.org
APPENDIXTop
The rest of the documentation details each of the object
methods. Internal methods are usually preceded with a _