Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://vo.astronet.ru/wiki/ranking
Дата изменения: Unknown Дата индексирования: Sat Apr 9 22:38:35 2016 Кодировка: Поисковые слова: ngc 5128 |
CREATE OR REPLACE FUNCTION my_rank (tsvector, tsquery, int ) RETURNS float AS $$ use List::Util qw(min max); my ($string, $query) = @_; my $maxpos = 0; # Parse tsvector, taking into account positional information foreach (split / /, $string){ if(/^'(\w+)'(:([0-9,]+))?$/){ foreach(split /,/, $3){ $vector{$_} = $1; $maxpos = max($maxpos, $_); } } } my @vector = map {$vector{$_}} sort {$a <=> $b} keys(%vector); # Parse tsquery, assuming it to be ORed only $query =~ s/[()|'']/ /g; $query =~ s/^\s+(.*?)\s+$/$1/; my @query = split /\s+/, $query; my %ndoc = {}; my %nentry = {}; my $rv = spi_exec_query("SELECT word,ndoc,nentry FROM wordstat WHERE ".join(' OR ', map {"word='$_'"} @query)); foreach my $i (0 .. $rv->{processed} - 1){ $ndoc{$rv->{rows}[$i]->{word}} = $rv->{rows}[$i]->{ndoc}; $nentry{$rv->{rows}[$i]->{word}} = $rv->{rows}[$i]->{nentry}; } my $rank = 0; foreach my $q (@query) { my $tf = scalar(grep {/^$q$/} @vector) / $maxpos; my $df = $ndoc{$q} || 0; if($tf > 0 && $df > 0) { $rank += $tf / log($df); } } return $rank; $$ LANGUAGE plperlU;
CREATE OR REPLACE FUNCTION my_rank (tsvector, tsquery) RETURNS float AS $$ my ($string, $query) = @_; # Parse tsvector. Use only words, not positional information my @vector = map /'(\w+)'/, split / /, $string; # Parse tsquery, assuming it to be ORed only $query =~ s/[()|'']/ /g; $query =~ s/^\s+(.*?)\s+$/$1/; my @query = split /\s+/, $query; # Number of query terms in the vector my $qlength = scalar(@query); # Number of matched terms my $qfound = scalar(map {my $q=$_; grep {/$q/} @vector} @query); # The more matched terms - the better my $rank_more = $qfound/$qlength; # The less matched terms - the better my $rank_less = ($qlength - $qfound + 1)/$qlength; # Middle way - prefer both single and all matches #my $rank_mid = 1 - $qfound*($qlength - $qfound + 1)/$qlength**2; my $rank_mid = ($rank_more > $rank_less ? $rank_more : $rank_less); return $rank_mid; $$ LANGUAGE plperl;
SELECT title, my_rank(fts, q) rank FROM apod, to_tsquery('english','sombrero|supernovae|milky|way|meteor') q WHERE fts @@ q ORDER BY rank DESC LIMIT 100;