Omnibox - Boost Frequency Scores Based on Number of Matching Pages

components/omnibox/browser/scored_history_match.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/omnibox/browser/scored_history_match.h"
 
 #include <math.h>
 
 #include <algorithm>
 #include <vector>
 
 #include "base/logging.h"
+#include "base/macros.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_offset_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/bookmarks/browser/bookmark_utils.h"
 #include "components/omnibox/browser/history_url_provider.h"
 #include "components/omnibox/browser/omnibox_field_trial.h"
 #include "components/omnibox/browser/url_prefix.h"
@@ skipping 95 matching lines @@
 // Default topicality threshold.  See GetTopicalityScore() for details.
 float ScoredHistoryMatch::topicality_threshold_ = 0.8f;
 
 // Default HQP relevance buckets. See GetFinalRelevancyScore() for more details
 // on these numbers.
 char ScoredHistoryMatch::hqp_relevance_buckets_str_[] =
     "0.0:400,1.5:600,5.0:900,10.5:1203,15.0:1300,20.0:1399";
 std::vector<ScoredHistoryMatch::ScoreMaxRelevance>*
     ScoredHistoryMatch::hqp_relevance_buckets_ = nullptr;
 
+OmniboxFieldTrial::NumMatchesScores*
+    ScoredHistoryMatch::num_matches_to_document_specificity_score_override_ =
+        nullptr;
+
 ScoredHistoryMatch::ScoredHistoryMatch()
     : ScoredHistoryMatch(history::URLRow(),
                          VisitInfoVector(),
                          base::string16(),
                          String16Vector(),
                          WordStarts(),
                          RowWordStarts(),
                          false,
-                         base::Time::Max()) {
-}
+                         1,
+                         base::Time::Max()) {}
 
 ScoredHistoryMatch::ScoredHistoryMatch(
     const history::URLRow& row,
     const VisitInfoVector& visits,
     const base::string16& lower_string,
     const String16Vector& terms_vector,
     const WordStarts& terms_to_word_starts_offsets,
     const RowWordStarts& word_starts,
     bool is_url_bookmarked,
+    size_t num_matching_pages,
     base::Time now)
     : HistoryMatch(row, 0, false, false), raw_score(0) {
   // NOTE: Call Init() before doing any validity checking to ensure that the
   // class is always initialized after an instance has been constructed. In
   // particular, this ensures that the class is initialized after an instance
   // has been constructed via the no-args constructor.
   ScoredHistoryMatch::Init();
 
   // Figure out where each search term appears in the URL and/or page title
   // so that we can score as well as provide autocomplete highlighting.
@@ skipping 97 matching lines @@
         likely_can_inline = true;
         innermost_match = (best_inlineable_prefix->num_components ==
                            best_prefix->num_components);
       }
     }
   }
 
   const float topicality_score = GetTopicalityScore(
       terms_vector.size(), url, terms_to_word_starts_offsets, word_starts);
   const float frequency_score = GetFrequency(now, is_url_bookmarked, visits);
-  raw_score = base::saturated_cast<int>(GetFinalRelevancyScore(
-      topicality_score, frequency_score, *hqp_relevance_buckets_));
+  const float specificity_score =
+      GetDocumentSpecificityScore(num_matching_pages);
+  raw_score = base::saturated_cast<int>(
+      GetFinalRelevancyScore(topicality_score, frequency_score,
+                             specificity_score, *hqp_relevance_buckets_));
 
   if (also_do_hup_like_scoring_ && likely_can_inline) {
     // HistoryURL-provider-like scoring gives any match that is
     // capable of being inlined a certain minimum score.  Some of these
     // are given a higher score that lets them be shown in inline.
     // This test here derives from the test in
     // HistoryURLProvider::PromoteMatchForInlineAutocomplete().
     const bool promote_to_inline =
         (row.typed_count() > 1) || (IsHostOnly() && (row.typed_count() == 1));
     int hup_like_score =
@@ skipping 333 matching lines @@
   // Compute the average weighted value_of_transition and return it.
   // Use |max_visits_to_score_| as the denominator for the average regardless of
   // how many visits there were in order to penalize a match that has
   // fewer visits than kMaxVisitsToScore.
   if (fix_few_visits_bug_)
     return summed_visit_points / ScoredHistoryMatch::max_visits_to_score_;
   return visits.size() * summed_visit_points /
          ScoredHistoryMatch::max_visits_to_score_;
 }
 
+float ScoredHistoryMatch::GetDocumentSpecificityScore(
+    size_t num_matching_pages) const {
+  // A mapping from the number of matching pages to their associated document
+  // specificity scores.  See omnibox_field_trial.h for more details.
+  CR_DEFINE_STATIC_LOCAL(OmniboxFieldTrial::NumMatchesScores,
+                         default_num_matches_to_document_specificity_score,
+                         (OmniboxFieldTrial::HQPNumMatchesScores()));
+  OmniboxFieldTrial::NumMatchesScores*
+      num_matches_to_document_specificity_score =
+          num_matches_to_document_specificity_score_override_
+              ? num_matches_to_document_specificity_score_override_
+              : &default_num_matches_to_document_specificity_score;

[Peter Kasting, 2016/12/10 02:22:26]

I feel like there might be a way to shorten all the names here and not have the
same text repeat over and over... |matches_to_specificity|?  I dunno.

[Mark P, 2016/12/11 05:11:37]

I was wondering if there was a good way to shorten the name that we'd both be
comfortable with.  It wasn't obvious.  Thank you for coming up with one.  Done.

+
+  // The floating point value below must be less than the lowest score the
+  // server would send down.
+  OmniboxFieldTrial::NumMatchesScores::const_iterator it =
+      std::upper_bound(num_matches_to_document_specificity_score->begin(),
+                       num_matches_to_document_specificity_score->end(),
+                       std::pair<size_t, double>{num_matching_pages, -1});
+  return (it != num_matches_to_document_specificity_score->end()) ? it->second
+                                                                  : 1.0;
+};
+
 // static
 float ScoredHistoryMatch::GetFinalRelevancyScore(
     float topicality_score,
     float frequency_score,
+    float specificity_score,
     const std::vector<ScoreMaxRelevance>& hqp_relevance_buckets) {
   DCHECK(hqp_relevance_buckets.size() > 0);
   DCHECK_EQ(hqp_relevance_buckets[0].first, 0.0);
 
   if (topicality_score == 0)
     return 0;
-  // Here's how to interpret intermediate_score: Suppose the omnibox
-  // has one input term.  Suppose we have a URL for which the omnibox
+  // Here's how to interpret intermediate_score: Suppose the omnibox has one
+  // input term.  Suppose the input matches many documents.  (This implies
+  // specificity_score == 1.0.)  Suppose we have a URL for which the omnibox
   // input term has a single URL hostname hit at a word boundary.  (This
   // implies topicality_score = 1.0.).  Then the intermediate_score for
   // this URL will depend entirely on the frequency_score with
   // this interpretation:
   // - a single typed visit more than three months ago, no other visits -> 0.2
   // - a visit every three days, no typed visits -> 0.706
   // - a visit every day, no typed visits -> 0.916
   // - a single typed visit yesterday, no other visits -> 2.0
   // - a typed visit once a week -> 11.77
   // - a typed visit every three days -> 14.12
   // - at least ten typed visits today -> 20.0 (maximum score)
   //
   // The below code maps intermediate_score to the range [0, 1399].
   // For example:
   // HQP default scoring buckets: "0.0:400,1.5:600,12.0:1300,20.0:1399"
   // We will linearly interpolate the scores between:
   //      0 to 1.5    --> 400 to 600
   //    1.5 to 12.0   --> 600 to 1300
   //    12.0 to 20.0  --> 1300 to 1399
   //       >= 20.0    --> 1399
   //
   // The score maxes out at 1399 (i.e., cannot beat a good inlineable result
   // from HistoryURL provider).
-  const float intermediate_score = topicality_score * frequency_score;
+  const float intermediate_score =
+      topicality_score * frequency_score * specificity_score;
 
   // Find the threshold where intermediate score is greater than bucket.
   size_t i = 1;
   for (; i < hqp_relevance_buckets.size(); ++i) {
     const ScoreMaxRelevance& hqp_bucket = hqp_relevance_buckets[i];
     if (intermediate_score >= hqp_bucket.first) {
       continue;
     }
     const ScoreMaxRelevance& previous_bucket = hqp_relevance_buckets[i - 1];
     const float slope = ((hqp_bucket.second - previous_bucket.second) /
@@ skipping 56 matching lines @@
           base::StringToDouble(it->first, &bucket.first);
       DCHECK(is_valid_intermediate_score);
       bool is_valid_hqp_score = base::StringToInt(it->second, &bucket.second);
       DCHECK(is_valid_hqp_score);
       hqp_buckets->push_back(bucket);
     }
     return true;
   }
   return false;
 }