Merge branch 'ntasks' into 'master'.

- Removes master as worker problem
- Resolves #6

Author: Joshua Bradt

include/ThreadPool.hh

@@ -26,22 +26,23 @@ public:
         void Finish();
 
         template <typename T, typename... Params>
-        void ParallelFor(uint32_t begin, uint32_t end, T SerialFunction, Params&&... params) {
+        void ParallelFor(uint32_t begin, uint32_t end, int32_t n_tasks, T SerialFunction, Params&&... params) {
 
-                int chunk = (end - begin) / m_nthreads;
-                for (int i = 0; i < m_nthreads; ++i) {
+                n_tasks = (n_tasks >= m_nthreads) ? n_tasks : m_nthreads;
+                int chunk = (end - begin) / n_tasks;
+                for (int i = 0; i < n_tasks; ++i) {
                         m_promises.emplace_back();
                         int mypromise = m_promises.size() - 1;
                         m_taskQueue.push([=]{
                                         uint32_t threadstart = begin + i*chunk;
-                                        uint32_t threadstop = (i == m_nthreads - 1) ? end : threadstart + chunk;
+                                        uint32_t threadstop = (i == n_tasks - 1) ? end : threadstart + chunk;
                                         for (uint32_t it = threadstart; it < threadstop; ++it) {
                                                 SerialFunction(it, params...);
                                         }
                                         m_promises[mypromise].set_value();
                                 });
                 }
-                m_taskQueue.pop()(); // master thread is also a worker
+                //m_taskQueue.pop()(); // master thread is also a worker
                 Finish();
         }
         template<typename InputIt, typename T>
@@ -61,7 +62,7 @@ public:
                     m_promises[mypromise].set_value(); // master thread is also a worker
                 });
             }
-            m_taskQueue.pop()();
+            //m_taskQueue.pop()();
             Finish();
         }
 

src/ThreadPool.cc

@@ -1,7 +1,8 @@
 #include "ThreadPool.hh"
 
 ThreadPool::ThreadPool(uint32_t numthreads) : m_nthreads(numthreads), m_stopWorkers(false) {
-    for (uint32_t i=0; i<numthreads-1;i++) { // -1 b/c main thread is also a worker
+    //for (uint32_t i=0; i<numthreads-1;i++) { // -1 b/c main thread is also a worker
+    for (uint32_t i=0; i<numthreads;i++) {
         m_workers.emplace_back(&ThreadPool::Worker, this);
     }
 }