Added a function to return the best tuning parameters to the user; fa…

…ctored out the logic to get the best tuning results

CHANGELOG

@@ -1,4 +1,8 @@
 
+Development branch (next version)
+- Added GetBestResult() to the tuner's API to retrieve the best parameters programmatically
+- Changed std::initalizer_list in the AddParameters API to std::vector
+
 Version 2.6.0
 - Changed timing measurements to now also include the (varying) kernel launch overhead
 - It is now possible to set OpenCL compiler options through the env variable CLTUNE_BUILD_OPTIONS

doc/api.md

@@ -89,6 +89,9 @@ Call this method *after* calling the `Tune()` method. Trains a machine learning
 Output
 -------------
 
+* `std::unordered_map<std::string, size_t> GetBestResult()`:
+Retrieves the parameters of the best tuning result and returns them to the caller as a map of strings (parameter names) to integers (parameter values).
+
 * `void OutputSearchLog(const std::string &filename)`:
 Outputs the search process to the file `filename`.
 

include/cltune.h

@@ -34,6 +34,7 @@
 #include <memory> // std::unique_ptr
 #include <functional> // std::function
 #include <utility> // std::pair
+#include <unordered_map> // std::unordered_map
 
 // Exports library functions under Windows when building a DLL. See also:
 // https://msdn.microsoft.com/en-us/library/a90k134d.aspx
@@ -144,6 +145,9 @@ class Tuner {
   void PUBLIC_API ModelPrediction(const Model model_type, const float validation_fraction,
                                   const size_t test_top_x_configurations);
 
+  // Retrieves the parameters of the best tuning result
+  std::unordered_map<std::string, size_t> GetBestResult() const;
+
   // Prints the results of the tuning either to screen (stdout) or to a specific output-file.
   // Returns the execution time in miliseconds.
   double PUBLIC_API PrintToScreen() const;

include/internal/tuner_impl.h

@@ -136,6 +136,9 @@ class TunerImpl {
   // Prints results of a particular kernel run
   void PrintResult(FILE* fp, const TunerResult &result, const std::string &message) const;
 
+  // Retrieves the best tuning result
+  TunerResult GetBestResult() const;
+
   // Loads a file from disk into a string
   std::string LoadFile(const std::string &filename);
 

src/cltune.cc

@@ -283,19 +283,27 @@ void Tuner::ModelPrediction(const Model model_type, const float validation_fract
 
 // =================================================================================================
 
+
+// Retrieves the parameters of the best tuning result
+std::unordered_map<std::string, size_t> Tuner::GetBestResult() const {
+  const auto best_result = pimpl->GetBestResult();
+  const auto best_configuration = best_result.configuration;
+
+  // Converts the std::vector<KernelInfo::Setting> into an unordere map of strings and integers
+  auto parameters = std::unordered_map<std::string, size_t>{};
+  for (const auto &parameter_setting : best_configuration) {
+    parameters[parameter_setting.name] = parameter_setting.value;
+  }
+  return parameters;
+}
+
 // Iterates over all tuning results and prints each parameter configuration and the corresponding
 // timing-results. Printing is to stdout.
 double Tuner::PrintToScreen() const {
 
   // Finds the best result
-  auto best_result = pimpl->tuning_results_[0];
-  auto best_time = std::numeric_limits<double>::max();
-  for (auto &tuning_result: pimpl->tuning_results_) {
-    if (tuning_result.status && best_time >= tuning_result.time) {
-      best_result = tuning_result;
-      best_time = tuning_result.time;
-    }
-  }
+  const auto best_result = pimpl->GetBestResult();
+  const auto best_time = best_result.time;
 
   // Aborts if there was no best time found
   if (best_time == std::numeric_limits<double>::max()) {
@@ -321,14 +329,8 @@ double Tuner::PrintToScreen() const {
 void Tuner::PrintFormatted() const {
 
   // Finds the best result
-  auto best_result = pimpl->tuning_results_[0];
-  auto best_time = std::numeric_limits<double>::max();
-  for (auto &tuning_result: pimpl->tuning_results_) {
-    if (tuning_result.status && best_time >= tuning_result.time) {
-      best_result = tuning_result;
-      best_time = tuning_result.time;
-    }
-  }
+  const auto best_result = pimpl->GetBestResult();
+  const auto best_time = best_result.time;
 
   // Prints the best result in C++ database format
   auto count = size_t{0};

src/tuner_impl.cc

@@ -646,6 +646,21 @@ void TunerImpl::PrintResult(FILE* fp, const TunerResult &result, const std::stri
 
 // =================================================================================================
 
+// Finds the best result
+TunerImpl::TunerResult TunerImpl::GetBestResult() const {
+  auto best_result = tuning_results_[0];
+  auto best_time = std::numeric_limits<double>::max();
+  for (auto &tuning_result: tuning_results_) {
+    if (tuning_result.status && best_time >= tuning_result.time) {
+      best_result = tuning_result;
+      best_time = tuning_result.time;
+    }
+  }
+  return best_result;
+}
+
+// =================================================================================================
+
 // Loads a file into a stringstream and returns the result as a string
 std::string TunerImpl::LoadFile(const std::string &filename) {
   std::ifstream file(filename);