Uplift of #21414 (squashed) to beta

brave · Dec 21, 2023 · 243e173 · 243e173
1 parent 732ae2c
commit 243e173
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Showing 3 changed files with 14 additions and 47 deletions.
diff --git a/components/brave_news/browser/feed_v2_builder.cc b/components/brave_news/browser/feed_v2_builder.cc
@@ -8,7 +8,6 @@
 
 #include <algorithm>
 #include <iterator>
-#include <locale>
 #include <numeric>
 #include <string>
 #include <tuple>
@@ -289,28 +288,6 @@ using GetWeighting =
     base::RepeatingCallback<double(const mojom::FeedItemMetadataPtr& metadata,
                                    const ArticleWeight& weight)>;
 
-// Returns a probability distribution (sum to 1) of the weights. Temperature
-// controls how "smooth" the distribution is. High temperature brings the
-// distribution closer to a uniform distribution (more randomness).
-// Low temperature brings the distribution closer to a delta function (less
-// randomness).
-void SoftmaxWithTemperature(
-    std::vector<double>& weights,
-    double temperature = features::kBraveNewsTemperature.Get()) {
-  if (temperature == 0) {
-    return;
-  }
-
-  double max = *base::ranges::max_element(weights.begin(), weights.end());
-  base::ranges::transform(weights.begin(), weights.end(), weights.begin(),
-                          [temperature, max](double weight) {
-                            return std::exp((weight - max) / temperature);
-                          });
-  double sum = std::accumulate(weights.begin(), weights.end(), 0.0);
-  base::ranges::transform(weights.begin(), weights.end(), weights.begin(),
-                          [sum](double weight) { return weight / sum; });
-}
-
 // Sample across subscribed channels (direct and native) and publishers.
 ContentGroup SampleContentGroup(
     const std::vector<ContentGroup>& eligible_content_groups) {
@@ -328,9 +305,11 @@ ContentGroup SampleContentGroup(
 // Picks an article with a probability article_weight/sum(article_weights).
 mojom::FeedItemMetadataPtr PickRouletteAndRemove(
     ArticleInfos& articles,
-    GetWeighting get_weighting = base::BindRepeating(
-        [](const mojom::FeedItemMetadataPtr& metadata,
-           const ArticleWeight& weight) { return weight.weighting; }),
+    GetWeighting get_weighting =
+        base::BindRepeating([](const mojom::FeedItemMetadataPtr& metadata,
+                               const ArticleWeight& weight) {
+          return weight.subscribed ? weight.weighting : 0;
+        }),
     bool use_softmax = false) {
   std::vector<double> weights;
   base::ranges::transform(articles, std::back_inserter(weights),
@@ -340,15 +319,12 @@ mojom::FeedItemMetadataPtr PickRouletteAndRemove(
                           });
 
   // None of the items are eligible to be picked.
-  if (std::accumulate(weights.begin(), weights.end(), 0.0) == 0) {
+  const auto total_weight =
+      std::accumulate(weights.begin(), weights.end(), 0.0);
+  if (total_weight == 0) {
     return nullptr;
   }
 
-  if (use_softmax) {
-    SoftmaxWithTemperature(weights);
-  }
-
-  double total_weight = std::accumulate(weights.begin(), weights.end(), 0.0);
   double picked_value = base::RandDouble() * total_weight;
   double current_weight = 0;
 
@@ -407,7 +383,7 @@ std::vector<mojom::FeedItemV2Ptr> GenerateBlock(
         auto image_url = metadata->image->is_padded_image_url()
                              ? metadata->image->get_padded_image_url()
                              : metadata->image->get_image_url();
-        return image_url.is_valid() ? weight.weighting : 0;
+        return image_url.is_valid() && weight.subscribed ? weight.weighting : 0;
       }));
 
   // We might not be able to generate a hero card, if none of the articles in
@@ -513,13 +489,12 @@ std::vector<mojom::FeedItemV2Ptr> GenerateBlockFromContentGroups(
 
   auto hero_article =
       PickRouletteAndRemove(articles, get_weighting(/*is_hero*/ true));
-  if (!hero_article) {
-    DVLOG(1) << "Failed to generate hero";
-    return result;
-  }
 
-  result.push_back(mojom::FeedItemV2::NewHero(
-      mojom::HeroArticle::New(std::move(hero_article))));
+  // This may fail if the the content group has no images.
+  if (hero_article) {
+    result.push_back(mojom::FeedItemV2::NewHero(
+        mojom::HeroArticle::New(std::move(hero_article))));
+  }
 
   const int block_min_inline = features::kBraveNewsMinBlockCards.Get();
   const int block_max_inline = features::kBraveNewsMaxBlockCards.Get();

diff --git a/components/brave_news/common/features.cc b/components/brave_news/common/features.cc
@@ -42,7 +42,4 @@ const base::FeatureParam<double> kBraveNewsSourceVisitsMin{
 const base::FeatureParam<double> kBraveNewsCategoryTopicRatio{
     &kBraveNewsFeedUpdate, "category-topic-ratio", 0.5};
 
-const base::FeatureParam<double> kBraveNewsTemperature{&kBraveNewsFeedUpdate,
-                                                       "temperature", 1};
-
 }  // namespace brave_news::features
diff --git a/components/brave_news/common/features.h b/components/brave_news/common/features.h
@@ -61,11 +61,6 @@ extern const base::FeatureParam<double> kBraveNewsSourceVisitsMin;
 // 80% of the clusters should be categories and 20% topics.
 extern const base::FeatureParam<double> kBraveNewsCategoryTopicRatio;
 
-// The temperature of the softmax function used to compute the sampling
-// probabilities of the articles in the feed. High temperature means the
-// distribution is more uniform.
-extern const base::FeatureParam<double> kBraveNewsTemperature;
-
 }  // namespace brave_news::features
 
 #endif  // BRAVE_COMPONENTS_BRAVE_NEWS_COMMON_FEATURES_H_