Completed implementation

task1/main.cpp

@@ -3,6 +3,7 @@
 #include <fstream>
 #include <string>
 #include <chrono>
+#include <cmath>
 
 #include <mergesort.h>
 #include <mergesort_mt.h>
@@ -39,17 +40,18 @@ auto parse_file(std::ifstream &stream, std::vector<T> &vec) -> void {
 
 auto main(int argc, char *argv[]) -> int {
     try {
-        std::ifstream file("dataset.dat", std::ios_base::in);
+        const auto path = "dataset.dat";
+        std::ifstream file(path, std::ios_base::in);
         if (!file.is_open()) {
-            fmt::print("Error opening file");
+            fmt::print("\nError opening file");
             return -1;
         }
 
-        fmt::print("Opened file {} sucessfully\n", "dummy");
+        fmt::print("\nOpened file {} sucessfully", path);
         std::vector<int32_t> dataset;
 
         parse_file(file, dataset);
-        fmt::print("Read {} values from {}\n", dataset.size(), "dummy");
+        fmt::print("\nRead {} values from {}", dataset.size(), path);
 
         auto dataset_par = dataset;
         auto dataset_seq = dataset;
@@ -60,37 +62,36 @@ auto main(int argc, char *argv[]) -> int {
         }, 0);
         auto t2 = std::chrono::high_resolution_clock::now();
 
-        auto delay_ms = std::chrono::duration_cast<std::chrono::milliseconds>(t2 - t1);
+        auto t_seq = std::chrono::duration_cast<std::chrono::milliseconds>(t2 - t1);
-        fmt::print("Sorted {} entries within {} ms in sequential\n", dataset_seq.size(), delay_ms.count());
+        fmt::print("\nSorted {} entries within {} ms in sequential", dataset_seq.size(), t_seq.count());
 
 
-        //const int max_depth = std::thread::hardware_concurrency();
+        const int threads = std::thread::hardware_concurrency();
-        const int max_depth = 4;
+        const int max_depth =  std::log(threads);
+
         t1 = std::chrono::high_resolution_clock::now();
-        MergeSorterMT<int> ms([](int a, int b) {
+        MergeSorterMT<int32_t > ms([](int32_t a, int32_t b) {
             return (a>b);
-        });
+        }, max_depth);
-        std::span t = dataset_par;
+        ms.sort(dataset_par);
-        int mdepth = 4;
-        std::recursive_mutex mut;
-        ms.split(t, 0, mdepth, mut);
-//        algo::MergeSort_mt::sort(dataset_par, [](int32_t a, int32_t b) {
-//            return (a > b);
-//        }, max_depth);
         t2 = std::chrono::high_resolution_clock::now();
 
-        delay_ms = std::chrono::duration_cast<std::chrono::milliseconds>(t2 - t1);
+        auto t_par = std::chrono::duration_cast<std::chrono::milliseconds>(t2 - t1);
-        fmt::print("Sorted {} entries within {} ms in parallel using {} threads\n", dataset_seq.size(), delay_ms.count(), max_depth);
+        fmt::print("\nSorted {} entries within {} ms in parallel using {} threads and a recursion depth of {}", dataset_seq.size(), t_par.count(), threads, max_depth);
 
         auto eq = (dataset_seq == dataset_par);
-        fmt::print("Equality: {}\n", eq);
+        fmt::print("\nCheck whether sorted arrays are equal: {}", (eq)? "Equal" : "not equal");
-        fmt::print("Parallel dataset: {}; Sequential dataset: {}\n", dataset_par.size(), dataset_seq.size());
 
-        //fmt::print("Created {} recurstions", algo::MergeSort_v1::get_recursions());
+        fmt::print("\n\n------------Summary------------");
+        fmt::print("\nt_seq   = {: > 5.2f} ms", static_cast<float>(t_seq.count()));
+        fmt::print("\nt_par   = {: > 5.2f} ms", static_cast<float>(t_par.count()));
+        fmt::print("\nspeedup = {: > 5.2f}", (1.0*t_seq/t_par));
+        fmt::print("\nDelta_t = {: > 5.2f} ms", static_cast<float>(t_seq.count() - t_par.count()));
+        fmt::print("\n-------------------------------");
 
         std::ofstream ofile("dataset.out.dat", std::ios_base::out);
         if(!ofile.is_open()) {
-            fmt::print("Error writing to file");
+            fmt::print("\nError writing to file");
             return -1;
         }
 
@@ -102,12 +103,12 @@ auto main(int argc, char *argv[]) -> int {
         ofile.flush();
         ofile.close();
 
-        fmt::print("Written to output file\n");
+        fmt::print("\nWritten to output file");
 
         return 0;
 
     } catch (std::exception &e) {
-        fmt::print("Error occured: {}", e.what());
+        fmt::print("\nError occured: {}", e.what());
         return -1;
     }
 

task1/mergesort_mt.h

@@ -8,14 +8,16 @@ class MergeSorterMT {
 
 public:
     template<typename C>
-    MergeSorterMT(C cmp) : cmp(cmp){
+    MergeSorterMT(C cmp, int max_depth) : cmp(cmp), max_depth(max_depth) {
         static_assert(std::is_same<std::invoke_result_t<C, T, T>, bool>(), "C must be a function that returns a bool");
     }
 
+    auto sort(std::vector<T> &data) -> void {
+        std::span<T> sortable(data);
+        split(sortable, 0, max_depth, mut);
+    }
 
-    std::function<bool(T, T)> cmp;
+private:
-    std::recursive_mutex mut;
-
     auto merge(std::span<T> &output, std::span<T> left, std::span<T> right) -> void {
         std::vector<T> buf;
         buf.reserve(left.size() + right.size());
@@ -46,39 +48,43 @@ public:
         }
 
         {
-            std::lock_guard<std::recursive_mutex> lock(mut);
+            //todo: is a lock guard necessary?
+            //std::lock_guard<std::recursive_mutex> lock(mut);
             std::move(buf.begin(), buf.end(), output.begin());
         }
     }
 
-    auto split(std::span<T> &data, int depth, int &max_depth, std::recursive_mutex &mut) -> void {
+    auto split(std::span<T> &data, int depth, const int &mdepth, std::recursive_mutex &mutex) -> void {
-        if(std::distance(data.begin(), data.end()) <= 1) {
+        if (std::distance(data.begin(), data.end()) <= 1) {
             return;
         }
 
         auto mid = data.begin();
-        std::advance(mid, std::distance(data.begin(), data.end())/2);
+        std::advance(mid, std::distance(data.begin(), data.end()) / 2);
 
         std::span<T> left(data.begin(), mid);
         std::span<T> right(mid, data.end());
 
-        if(depth < max_depth) {
+        if (depth < mdepth) {
-            //std::thread left_thread(&MergeSorterMT::split, this, left, depth + 1, max_depth, mut);
+            //todo: fix lambda call
-            //std::thread right_thread(&MergeSorterMT::split, this, right, depth + 1, max_depth, mut);
+            //std::thread left_thread(&MergeSorterMT::split, this, left, depth + 1, mdepth, mutex);
-            std::thread left_thread([&](){split(left, depth + 1, max_depth, mut);});
+            //std::thread right_thread(&MergeSorterMT::split, this, right, depth + 1, mdepth, mutex);
-            std::thread right_thread([&](){split(right, depth + 1, max_depth, mut);});
+            std::thread left_thread([&]() { split(left, depth + 1, mdepth, mutex); });
+            std::thread right_thread([&]() { split(right, depth + 1, mdepth, mutex); });
 
             left_thread.join();
             right_thread.join();
         } else {
-            split(left, depth + 1, max_depth, mut);
+            split(left, depth + 1, mdepth, mutex);
-            split(right, depth + 1, max_depth, mut);
+            split(right, depth + 1, mdepth, mutex);
         }
 
         merge(data, left, right);
     }
 
 
-
+private:
-
+    std::function<bool(T, T)> cmp;
+    const int max_depth;
+    std::recursive_mutex mut;
 };