feat: use less threads for short lists

QVectorSearch/mainwindow.cpp

@@ -33,7 +33,7 @@ void MainWindow::setupAlgorithmSelector() {
 
 void MainWindow::generateWordList() {
   Timer timer;
-  word_list_ = WordListGenerator().generate();
+  word_list_ = WordListGenerator::generate();
   timer.stop();
 
   std::stringstream status_message;

lib_vector_search/include/word_list_generator.h

@@ -8,5 +8,6 @@ private:
   static const std::string charset_;
 
 public:
-  std::vector<std::string> generate();
+  WordListGenerator() = delete;
+  static std::vector<std::string> generate(const size_t multiplier = 1);
 };

lib_vector_search/src/grouped_finder.cpp

@@ -22,7 +22,8 @@ GroupedFinder::find_prefix(std::string_view search_term) const {
   const auto word_list = group->second;
   const auto word_list_size = word_list.size();
 
-  const auto thread_count = std::thread::hardware_concurrency();
+  const auto thread_count =
+      std::min<size_t>(std::thread::hardware_concurrency(), word_list_size);
 
   forward_list<const string *> matching_words;
   mutex matching_words_mutex;

lib_vector_search/src/word_list_generator.cpp

@@ -6,18 +6,16 @@
 
 const std::string WordListGenerator::charset_ = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
-std::vector<std::string> WordListGenerator::generate() {
-  const size_t multiplier = 1;
-
-  std::vector<std::string> result;
-  result.reserve(multiplier * std::pow(charset_.length(), 4));
+std::vector<std::string> WordListGenerator::generate(const size_t multiplier) {
+  std::vector<std::string> word_list;
+  word_list.reserve(multiplier * std::pow(charset_.length(), 4));
 
   for (auto char_1 : charset_) {
     for (auto char_2 : charset_) {
       for (auto char_3 : charset_) {
         for (auto char_4 : charset_) {
           for (auto i = 0; i < multiplier; ++i) {
-            result.emplace_back(
+            word_list.emplace_back(
                 std::initializer_list<char>({char_1, char_2, char_3, char_4}));
           }
         }
@@ -28,7 +26,7 @@ std::vector<std::string> WordListGenerator::generate() {
   std::random_device random_device;
   std::mt19937 random_number_generator(random_device());
 
-  std::shuffle(result.begin(), result.end(), random_number_generator);
+  std::shuffle(word_list.begin(), word_list.end(), random_number_generator);
 
-  return result;
+  return word_list;
 }

vector_search_cli/main.cpp

@@ -14,7 +14,7 @@ vector<string> generate_word_list() {
   cout << "\ngenerating word list" << endl;
 
   Timer generator_timer;
-  auto word_list = WordListGenerator().generate();
+  auto word_list = WordListGenerator::generate(5);
   generator_timer.stop();
 
   cout << "word list generator took " << generator_timer << endl;