Christopher Fields > BioPerl > Bio::Search::Hit::ModelHit



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Bio::Search::Hit::ModelHit - A model-based implementation of the Bio::Search::Hit::HitI interface


    use Bio::Search::Hit::ModelHit;
    my $hit = Bio::Search::Hit::ModelHit->new(-algorithm => 'rnamotif');

    # typically one gets HitI objects from a SearchIO stream via a ResultI
    use Bio::SearchIO;
    my $parser = Bio::SearchIO->new(-format => 'infernal', -file => 'trap.inf');

    my $result = $parser->next_result;
    my $hit    = $result->next_hit;


This object handles the hit data from a database search using models or descriptors instead of sequences, such as Infernal, HMMER, RNAMotif, etc.

Unless you're writing a parser, you won't ever need to create a ModelHit or any other HitI-implementing object. If you use the SearchIO system, HitI objects are created automatically from a SearchIO stream which returns Bio::Search::Hit::HitI objects.

Note that several HitI-based methods have been overridden from ModelHit due to their unreliability when dealing with queries that aren't sequence-based. It may be possible to reimplement these at a later point, but for the time being they will throw warnings and return w/o results.

For documentation on what you can do with ModelHit (and other HitI objects), please see the API documentation in Bio::Search::Hit::HitI.


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User feedback is an integral part of the evolution of this and other Bioperl modules. Send your comments and suggestions preferably to the Bioperl mailing list. Your participation is much appreciated.                  - General discussion  - About the mailing lists


Please direct usage questions or support issues to the mailing list:

rather than to the module maintainer directly. Many experienced and reponsive experts will be able look at the problem and quickly address it. Please include a thorough description of the problem with code and data examples if at all possible.

Reporting Bugs

Report bugs to the Bioperl bug tracking system to help us keep track of the bugs and their resolution. Bug reports can be submitted via the web:

AUTHOR - Chris Fields ^

Email cjfields at bioperl dot org


The rest of the documentation details each of the object methods. Internal methods are usually preceded with a _

HitI methods implemented in parent class Bio::Search::Hit::ModelHit ^


 Title   : new
 Usage   : my $obj = Bio::Search::Hit::ModelHit->new();
 Function: Builds a new Bio::Search::Hit::ModelHit object
 Returns : Bio::Search::Hit::ModelHit
 Args    : -name         => Name of Hit (required)
           -description  => Description (optional)
           -accession    => Accession number (optional)
           -ncbi_gi      => NCBI GI UID (optional)
           -length       => Length of the Hit (optional)
           -score        => Raw Score for the Hit (optional)
           -bits         => Bit Score for the Hit (optional)
           -significance => Significance value for the Hit (optional)
           -algorithm    => Algorithm used (BLASTP, FASTX, etc...)
           -hsps         => Array ref of HSPs for this Hit.
           -found_again  => boolean, true if hit appears in a
                            "previously found" section of a PSI-Blast report.
           -hsp_factory  => Bio::Factory::ObjectFactoryI able to create HSPI


 Title   : add_hsp
 Usage   : $hit->add_hsp($hsp)
 Function: Add a HSP to the collection of HSPs for a Hit
 Returns : number of HSPs in the Hit
 Args    : Bio::Search::HSP::HSPI object, OR hash ref containing data suitable
           for creating a HSPI object (&hsp_factory must be set to get it back)


 Title   : hsp_factory
 Usage   : $hit->hsp_factory($hsp_factory)
 Function: Get/set the factory used to build HSPI objects if necessary.
 Returns : Bio::Factory::ObjectFactoryI
 Args    : Bio::Factory::ObjectFactoryI

Bio::Search::Hit::HitI methods

Implementation of Bio::Search::Hit::HitI methods


 Title   : name
 Usage   : $hit_name = $hit->name();
 Function: returns the name of the Hit sequence
 Returns : a scalar string
 Args    : [optional] scalar string to set the name


 Title   : accession
 Usage   : $acc = $hit->accession();
 Function: Retrieve the accession (if available) for the hit
 Returns : a scalar string (empty string if not set)
 Args    : none


 Title   : description
 Usage   : $desc = $hit->description();
 Function: Retrieve the description for the hit
 Returns : a scalar string
 Args    : [optional] scalar string to set the descrition


 Title   : length
 Usage   : my $len = $hit->length
 Function: Returns the length of the hit
 Returns : integer
 Args    : [optional] integer to set the length


 Title   : algorithm
 Usage   : $alg = $hit->algorithm();
 Function: Gets the algorithm specification that was used to obtain the hit
           For BLAST, the algorithm denotes what type of sequence was aligned
           against what (BLASTN: dna-dna, BLASTP prt-prt, BLASTX translated
           dna-prt, TBLASTN prt-translated dna, TBLASTX translated
           dna-translated dna).
 Returns : a scalar string
 Args    : [optional] scalar string to set the algorithm


 Title   : raw_score
 Usage   : $score = $hit->raw_score();
 Function: Gets the "raw score" generated by the algorithm.  What
           this score is exactly will vary from algorithm to algorithm,
           returning undef if unavailable.
 Returns : a scalar value
 Args    : [optional] scalar value to set the raw score


Equivalent to raw_score()


 Title   : significance
 Usage   : $significance = $hit->significance();
 Function: Used to obtain the E or P value of a hit, i.e. the probability that
           this particular hit was obtained purely by random chance.  If
           information is not available (nor calculatable from other
           information sources), return undef.
 Returns : a scalar value or undef if unavailable
 Args    : [optional] scalar value to set the significance


 Usage     : $hit_object->bits();
 Purpose   : Gets the bit score of the best HSP for the current hit.
 Example   : $bits = $hit_object->bits();
 Returns   : Integer or undef if bit score is not set
 Argument  : n/a
 Comments  : For BLAST1, the non-bit score is listed in the summary line.

See Also : score()


 Title    : next_hsp
 Usage    : while( $hsp = $obj->next_hsp()) { ... }
 Function : Returns the next available High Scoring Pair
 Example  :
 Returns  : Bio::Search::HSP::HSPI object or null if finished
 Args     : none


 Usage     : $hit_object->hsps();
 Purpose   : Get a list containing all HSP objects.
           : Get the numbers of HSPs for the current hit.
 Example   : @hsps = $hit_object->hsps();
           : $num  = $hit_object->hsps();  # alternatively, use num_hsps()
 Returns   : Array context : list of objects.
           : Scalar context: integer (number of HSPs).
           :                 (Equivalent to num_hsps()).
 Argument  : n/a. Relies on wantarray
 Throws    : Exception if the HSPs have not been collected.

See Also : hsp(), num_hsps()


 Usage     : $hit_object->num_hsps();
 Purpose   : Get the number of HSPs for the present hit.
 Example   : $nhsps = $hit_object->num_hsps();
 Returns   : Integer or '-' if HSPs have not been callected
 Argument  : n/a

See Also : hsps()


 Title   : rewind
 Usage   : $hit->rewind;
 Function: Allow one to reset the HSP iterator to the beginning
           Since this is an in-memory implementation
 Returns : none
 Args    : none


 Usage     : $ambig_code = $hit_object->ambiguous_aln();
 Purpose   : Sets/Gets ambiguity code data member.
 Example   : (see usage)
 Returns   : String = 'q', 's', 'qs', '-'
           :   'q'  = query sequence contains overlapping sub-sequences
           :          while sbjct does not.
           :   's'  = sbjct sequence contains overlapping sub-sequences
           :          while query does not.
           :   'qs' = query and sbjct sequence contains overlapping sub-sequences
           :          relative to each other.
           :   '-'  = query and sbjct sequence do not contains multiple domains
           :          relative to each other OR both contain the same distribution
           :          of similar domains.
 Argument  : n/a
 Throws    : n/a
 Comment   : Note: "sbjct" is synonymous with "hit"


See documentation in Bio::Search::Hit::HitI::overlap()


 Usage     : $hit_object->n();
 Purpose   : Gets the N number for the current hit.
           : This is the number of HSPs in the set which was ascribed
           : the lowest P-value (listed on the description line).
           : This number is not the same as the total number of HSPs.
           : To get the total number of HSPs, use num_hsps().
 Example   : $n = $hit_object->n();
 Returns   : Integer
 Argument  : n/a
 Throws    : Exception if HSPs have not been set.
 Comments  : Calling n() on such reports will result in a call to num_hsps().
           : The num_hsps() method will count the actual number of
           : HSPs in the alignment listing, which may exceed N in
           : some cases.

See Also : num_hsps()


 Usage     : $hit_object->p( [format] );
 Purpose   : Get the P-value for the best HSP
 Example   : $p =  $sbjct->p;
           : $p =  $sbjct->p('exp');  # get exponent only.
           : ($num, $exp) =  $sbjct->p('parts');  # split sci notation into parts
 Returns   : Float or scientific notation number (the raw P-value, DEFAULT).
           : Integer if format == 'exp' (the magnitude of the base 10 exponent).
           : 2-element list (float, int) if format == 'parts' and P-value
           :                is in scientific notation (See Comments).
 Argument  : format: string of 'raw' | 'exp' | 'parts'
           :    'raw' returns value given in report. Default. (1.2e-34)
           :    'exp' returns exponent value only (34)
           :    'parts' returns the decimal and exponent as a
           :            2-element list (1.2, -34) (See Comments).
 Throws    : Warns if no P-value is defined. Uses expect instead.
 Comments  : Using the 'parts' argument is not recommended since it will not
           : work as expected if the P-value is not in scientific notation.
           : That is, floats are not converted into sci notation before
           : splitting into parts.

See Also : expect(), signif(), Bio::Search::SearchUtils::get_exponent()


 Usage     : $hit_object->hsp( [string] );
 Purpose   : Get a single HSPI object for the present HitI object.
 Example   : $hspObj  = $hit_object->hsp;  # same as 'best'
           : $hspObj  = $hit_object->hsp('best');
           : $hspObj  = $hit_object->hsp('worst');
 Returns   : Object reference for a object.
 Argument  : String (or no argument).
           :   No argument (default) = highest scoring HSP (same as 'best').
           :   'best' or 'first' = highest scoring HSP.
           :   'worst' or 'last' = lowest scoring HSP.
 Throws    : Exception if the HSPs have not been collected.
           : Exception if an unrecognized argument is used.

See Also : hsps(), num_hsps()


 Title   : rank
 Usage   : $obj->rank($newval)
 Function: Get/Set the rank of this Hit in the Query search list
           i.e. this is the Nth hit for a specific query
 Returns : value of rank
 Args    : newvalue (optional)


 Title   : locus
 Usage   : $locus = $hit->locus();
 Function: Retrieve the locus (if available) for the hit
 Returns : a scalar string (empty string if not set)
 Args    : none


 Title   : each_accession_number
 Usage   : @each_accession_number = $hit->each_accession_number();
 Function: Get each accession number listed in the description of the hit.
           If there are no alternatives, then only the primary accession will
           be given
 Returns : list of all accession numbers in the description
 Args    : none


See documentation in Bio::Search::SearchUtils::tile_hsps()


 Title   : query_length
 Usage   : $obj->query_length($newval)
 Function: Get/Set the query_length
 Returns : value of query_length (a scalar)
 Args    : on set, new value (a scalar or undef, optional)


 Title   : ncbi_gi
 Usage   : $acc = $hit->ncbi_gi();
 Function: Retrieve the NCBI Unique ID (aka the GI #),
           if available, for the hit
 Returns : a scalar string (empty string if not set)
 Args    : none

ModelHit methods overridden in ModelHit ^

The following methods have been overridden due to their current reliance on sequence-based queries. They may be implemented in future versions of this class.

















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