multiterm.php

很棒的在线教学系统

            } else {
                //$this->_resVector = array_intersect_key($this->_resVector, $nextResVector);
                
                /**
                 * This code is used as workaround for array_intersect_key() slowness problem.
                 */
                $updatedVector = array();
                foreach ($this->_resVector as $id => $value) {
                    if (isset($nextResVector[$id])) {
                        $updatedVector[$id] = $value;
                    }
                }
                $this->_resVector = $updatedVector;
            }

            if (count($this->_resVector) == 0) {
                // Empty result set, we don't need to check other terms
                break;
            }
        }

        // ksort($this->_resVector, SORT_NUMERIC);
        // Docs are returned ordered. Used algorithm doesn't change elements order.
    }


    /**
     * Calculate result vector for non Conjunction query
     * (like '+something -another')
     *
     * @param Zend_Search_Lucene_Interface $reader
     */
    private function _calculateNonConjunctionResult(Zend_Search_Lucene_Interface $reader)
    {
        $requiredVectors      = array();
        $requiredVectorsSizes = array();
        $requiredVectorsIds   = array(); // is used to prevent arrays comparison
        
        $optional   = array();
        $prohibited = array();
        
        foreach ($this->_terms as $termId => $term) {
            $termDocs = array_flip($reader->termDocs($term));

            if ($this->_signs[$termId] === true) {
                // required
                $requiredVectors[]      = $termDocs;
                $requiredVectorsSizes[] = count($termDocs);
                $requiredVectorsIds[]   = $termId;
            } elseif ($this->_signs[$termId] === false) {
                // prohibited
                // array union
                $prohibited += $termDocs;
            } else {
                // neither required, nor prohibited
                // array union
                $optional += $termDocs;
            }

            $this->_termsFreqs[$termId] = $reader->termFreqs($term);
        }

        // sort resvectors in order of subquery cardinality increasing
        array_multisort($requiredVectorsSizes, SORT_ASC, SORT_NUMERIC,
                        $requiredVectorsIds,   SORT_ASC, SORT_NUMERIC,
                        $requiredVectors);
        
        $required = null;
        foreach ($requiredVectors as $nextResVector) {
            if($required === null) {
                $required = $nextResVector;
            } else {
                //$required = array_intersect_key($required, $nextResVector);
                
                /**
                 * This code is used as workaround for array_intersect_key() slowness problem.
                 */
                $updatedVector = array();
                foreach ($required as $id => $value) {
                    if (isset($nextResVector[$id])) {
                        $updatedVector[$id] = $value;
                    }
                }
                $required = $updatedVector;
            }

            if (count($required) == 0) {
                // Empty result set, we don't need to check other terms
                break;
            }
        }
                
        if ($required !== null) {
            $this->_resVector = $required;
        } else {
            $this->_resVector = $optional;
        }

        if (count($prohibited) != 0) {
            // $this->_resVector = array_diff_key($this->_resVector, $prohibited);
            
            /**
             * This code is used as workaround for array_diff_key() slowness problem.
             */
            if (count($this->_resVector) < count($prohibited)) {
                $updatedVector = $this->_resVector;
                foreach ($this->_resVector as $id => $value) {
                    if (isset($prohibited[$id])) {
                        unset($updatedVector[$id]);
                    }
                }
                $this->_resVector = $updatedVector;
            } else {
                $updatedVector = $this->_resVector;
                foreach ($prohibited as $id => $value) {
                    unset($updatedVector[$id]);
                }
                $this->_resVector = $updatedVector;
            }
        }
        
        ksort($this->_resVector, SORT_NUMERIC);
    }


    /**
     * Score calculator for conjunction queries (all terms are required)
     *
     * @param integer $docId
     * @param Zend_Search_Lucene_Interface $reader
     * @return float
     */
    public function _conjunctionScore($docId, Zend_Search_Lucene_Interface $reader)
    {
        if ($this->_coord === null) {
            $this->_coord = $reader->getSimilarity()->coord(count($this->_terms),
                                                            count($this->_terms) );
        }

        $score = 0.0;

        foreach ($this->_terms as $termId=>$term) {
            /**
             * We don't need to check that term freq is not 0
             * Score calculation is performed only for matched docs
             */
            $score += $reader->getSimilarity()->tf($this->_termsFreqs[$termId][$docId]) *
                      $this->_weights[$termId]->getValue() *
                      $reader->norm($docId, $term->field);
        }

        return $score * $this->_coord * $this->getBoost();
    }


    /**
     * Score calculator for non conjunction queries (not all terms are required)
     *
     * @param integer $docId
     * @param Zend_Search_Lucene_Interface $reader
     * @return float
     */
    public function _nonConjunctionScore($docId, $reader)
    {
        if ($this->_coord === null) {
            $this->_coord = array();

            $maxCoord = 0;
            foreach ($this->_signs as $sign) {
                if ($sign !== false /* not prohibited */) {
                    $maxCoord++;
                }
            }

            for ($count = 0; $count <= $maxCoord; $count++) {
                $this->_coord[$count] = $reader->getSimilarity()->coord($count, $maxCoord);
            }
        }

        $score = 0.0;
        $matchedTerms = 0;
        foreach ($this->_terms as $termId=>$term) {
            // Check if term is
            if ($this->_signs[$termId] !== false &&        // not prohibited
                isset($this->_termsFreqs[$termId][$docId]) // matched
               ) {
                $matchedTerms++;

                /**
                 * We don't need to check that term freq is not 0
                 * Score calculation is performed only for matched docs
                 */
                $score +=
                      $reader->getSimilarity()->tf($this->_termsFreqs[$termId][$docId]) *
                      $this->_weights[$termId]->getValue() *
                      $reader->norm($docId, $term->field);
            }
        }

        return $score * $this->_coord[$matchedTerms] * $this->getBoost();
    }

    /**
     * Execute query in context of index reader
     * It also initializes necessary internal structures
     *
     * @param Zend_Search_Lucene_Interface $reader
     */
    public function execute(Zend_Search_Lucene_Interface $reader)
    {
        if ($this->_signs === null) {
            $this->_calculateConjunctionResult($reader);
        } else {
            $this->_calculateNonConjunctionResult($reader);
        }

        // Initialize weight if it's not done yet
        $this->_initWeight($reader);
    }

    /**
     * Get document ids likely matching the query
     *
     * It's an array with document ids as keys (performance considerations)
     *
     * @return array
     */
    public function matchedDocs()
    {
        return $this->_resVector;
    }

    /**
     * Score specified document
     *
     * @param integer $docId
     * @param Zend_Search_Lucene_Interface $reader
     * @return float
     */
    public function score($docId, Zend_Search_Lucene_Interface $reader)
    {
        if (isset($this->_resVector[$docId])) {
            if ($this->_signs === null) {
                return $this->_conjunctionScore($docId, $reader);
            } else {
                return $this->_nonConjunctionScore($docId, $reader);
            }
        } else {
            return 0;
        }
    }

    /**
     * Return query terms
     *
     * @return array
     */
    public function getQueryTerms()
    {
        if ($this->_signs === null) {
            return $this->_terms;
        }

        $terms = array();

        foreach ($this->_signs as $id => $sign) {
            if ($sign !== false) {
                $terms[] = $this->_terms[$id];
            }
        }

        return $terms;
    }

    /**
     * Highlight query terms
     *
     * @param integer &$colorIndex
     * @param Zend_Search_Lucene_Document_Html $doc
     */
    public function highlightMatchesDOM(Zend_Search_Lucene_Document_Html $doc, &$colorIndex)
    {
        $words = array();

        if ($this->_signs === null) {
            foreach ($this->_terms as $term) {
                $words[] = $term->text;
            }
        } else {
            foreach ($this->_signs as $id => $sign) {
                if ($sign !== false) {
                    $words[] = $this->_terms[$id]->text;
                }
            }
        }

        $doc->highlight($words, $this->_getHighlightColor($colorIndex));
    }

    /**
     * Print a query
     *
     * @return string
     */
    public function __toString()
    {
        // It's used only for query visualisation, so we don't care about characters escaping

        $query = '';

        foreach ($this->_terms as $id => $term) {
            if ($id != 0) {
                $query .= ' ';
            }

            if ($this->_signs === null || $this->_signs[$id] === true) {
                $query .= '+';
            } else if ($this->_signs[$id] === false) {
                $query .= '-';
            }

            if ($term->field !== null) {
                $query .= $term->field . ':';
            }
            $query .= $term->text;
        }

        if ($this->getBoost() != 1) {
            $query = '(' . $query . ')^' . $this->getBoost();
        }

        return $query;
    }
}