From 452780ee89a48109e3d27b8c230f09dfa235fb19 Mon Sep 17 00:00:00 2001
From: Vladyslav Usenko <usenko.vladyslav@gmail.com>
Date: Sun, 9 Jun 2019 10:29:40 +0200
Subject: [PATCH] Small updates HashBow

---
 include/basalt/hash_bow/hash_bow.h  | 15 ++++++++-------
 include/basalt/utils/common_types.h |  2 +-
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/include/basalt/hash_bow/hash_bow.h b/include/basalt/hash_bow/hash_bow.h
index 0c658d2..a2936f0 100644
--- a/include/basalt/hash_bow/hash_bow.h
+++ b/include/basalt/hash_bow/hash_bow.h
@@ -35,23 +35,24 @@ class HashBow {
     size_t descriptors_size = descriptors.size();
     hashes.resize(descriptors_size);
 
-    bow_vector.clear();
-    bow_vector.reserve(descriptors_size);
+    std::unordered_map<FeatureHash, double> bow_map;
+    bow_map.clear();
+    bow_map.reserve(descriptors_size);
 
     for (size_t i = 0; i < descriptors_size; i++) {
       hashes[i] = compute_hash(descriptors[i]);
-
-      FeatureHash bow_word = hashes[i];
-      bow_vector[bow_word] += 1.0;
+      bow_map[hashes[i]] += 1.0;
     }
 
+    bow_vector.clear();
+
     double sum_squared = 0;
-    for (const auto& kv : bow_vector) {
+    for (const auto& kv : bow_map) {
+      bow_vector.emplace_back(kv);
       sum_squared += kv.second * kv.second;
     }
 
     double norm = std::sqrt(sum_squared);
-
     for (auto& kv : bow_vector) {
       kv.second /= norm;
     }
diff --git a/include/basalt/utils/common_types.h b/include/basalt/utils/common_types.h
index e3d9a2e..dc983dc 100644
--- a/include/basalt/utils/common_types.h
+++ b/include/basalt/utils/common_types.h
@@ -66,7 +66,7 @@ inline std::ostream& operator<<(std::ostream& os, const TimeCamId& tcid) {
 
 constexpr static const size_t FEATURE_HASH_MAX_SIZE = 32;
 using FeatureHash = std::bitset<FEATURE_HASH_MAX_SIZE>;
-using HashBowVector = std::unordered_map<FeatureHash, double>;
+using HashBowVector = std::vector<std::pair<FeatureHash, double>>;
 
 /// keypoint positions and descriptors for an image
 struct KeypointsData {