Add Thread max spawning to Network

bayesnet/network/Network.cc

@@ -6,6 +6,7 @@
 
 #include <thread>
 #include <mutex>
+#include <semaphore>
 #include <sstream>
 #include <numeric>
 #include "Network.h"
@@ -13,10 +14,17 @@
 namespace bayesnet {
     Network::Network() : fitted{ false }, maxThreads{ 0.95 }, classNumStates{ 0 }
     {
+        maxThreadsRunning = static_cast<int>(std::thread::hardware_concurrency() * maxThreads);
+        if (maxThreadsRunning < 1) {
+            maxThreadsRunning = 1;
+        }
     }
     Network::Network(float maxT) : fitted{ false }, maxThreads{ maxT }, classNumStates{ 0 }
     {
-
+        maxThreadsRunning = static_cast<int>(std::thread::hardware_concurrency() * maxThreads);
+        if (maxThreadsRunning < 1 || maxT > 1) {
+            maxThreadsRunning = 1;
+        }
     }
     Network::Network(const Network& other) : features(other.features), className(other.className), classNumStates(other.getClassNumStates()),
         maxThreads(other.getMaxThreads()), fitted(other.fitted), samples(other.samples)
@@ -192,30 +200,52 @@ namespace bayesnet {
     {
         setStates(states);
         std::vector<std::thread> threads;
+        std::mutex mtx;
+        std::condition_variable cv;
+        size_t activeThreads = 0;
         const double n_samples = static_cast<double>(samples.size(1));
+
+        auto worker = [&](std::pair<const std::string, std::unique_ptr<Node>>& node) {
+            {
+                std::unique_lock<std::mutex> lock(mtx);
+                cv.wait(lock, [&] { return activeThreads < maxThreadsRunning; });
+                ++activeThreads;
+            }
+
+            double numStates = static_cast<double>(node.second->getNumStates());
+            double smoothing_factor = 0.0;
+
+            switch (smoothing) {
+                case Smoothing_t::ORIGINAL:
+                    smoothing_factor = 1.0 / n_samples;
+                    break;
+                case Smoothing_t::LAPLACE:
+                    smoothing_factor = 1.0;
+                    break;
+                case Smoothing_t::CESTNIK:
+                    smoothing_factor = 1 / numStates;
+                    break;
+                default:
+                    throw std::invalid_argument("Smoothing method not recognized " + std::to_string(static_cast<int>(smoothing)));
+            }
+
+            node.second->computeCPT(samples, features, smoothing_factor, weights);
+
+            {
+                std::lock_guard<std::mutex> lock(mtx);
+                --activeThreads;
+            }
+            cv.notify_one();
+            };
+
         for (auto& node : nodes) {
-            threads.emplace_back([this, &node, &weights, n_samples, smoothing]() {
-                double numStates = static_cast<double>(node.second->getNumStates());
-                double smoothing_factor = 0.0;
-                switch (smoothing) {
-                    case Smoothing_t::ORIGINAL:
-                        smoothing_factor = 1.0 / n_samples;
-                        break;
-                    case Smoothing_t::LAPLACE:
-                        smoothing_factor = 1.0;
-                        break;
-                    case Smoothing_t::CESTNIK: // Considering m=1 pa = 1/numStates
-                        smoothing_factor = 1 / numStates;
-                        break;
-                    default:
-                        throw std::invalid_argument("Smoothing method not recognized " + std::to_string(static_cast<int>(smoothing)));
-                }
-                node.second->computeCPT(samples, features, smoothing_factor, weights);
-                });
+            threads.emplace_back(worker, std::ref(node));
         }
+
         for (auto& thread : threads) {
             thread.join();
         }
+
         fitted = true;
     }
     torch::Tensor Network::predict_tensor(const torch::Tensor& samples, const bool proba)
@@ -340,15 +370,32 @@ namespace bayesnet {
         std::vector<double> result(classNumStates, 0.0);
         std::vector<std::thread> threads;
         std::mutex mtx;
-        for (int i = 0; i < classNumStates; ++i) {
-            threads.emplace_back([this, &result, &evidence, i, &mtx]() {
-                auto completeEvidence = std::map<std::string, int>(evidence);
-                completeEvidence[getClassName()] = i;
-                double factor = computeFactor(completeEvidence);
+        std::condition_variable cv;
+        size_t activeThreads = 0;
+
+        auto worker = [&](int i) {
+            {
+                std::unique_lock<std::mutex> lock(mtx);
+                cv.wait(lock, [&] { return activeThreads < maxThreadsRunning; });
+                ++activeThreads;
+            }
+
+            auto completeEvidence = std::map<std::string, int>(evidence);
+            completeEvidence[getClassName()] = i;
+            double factor = computeFactor(completeEvidence);
+
+            {
                 std::lock_guard<std::mutex> lock(mtx);
                 result[i] = factor;
-                });
+                --activeThreads;
+            }
+            cv.notify_one();
+            };
+
+        for (int i = 0; i < classNumStates; ++i) {
+            threads.emplace_back(worker, i);
         }
+
         for (auto& thread : threads) {
             thread.join();
         }

bayesnet/network/Network.h

@@ -56,7 +56,8 @@ namespace bayesnet {
     private:
         std::map<std::string, std::unique_ptr<Node>> nodes;
         bool fitted;
-        float maxThreads = 0.95;
+        float maxThreads = 0.95; // Coefficient to multiply by the number of threads available
+        int maxThreadsRunning; // Effective max number of threads running
         int classNumStates;
         std::vector<std::string> features; // Including classname
         std::string className;