2_parallel_reduce.h

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#pragma once
 
#include "gts/micro_scheduler/WorkerPool.h"
#include "gts/micro_scheduler/MicroScheduler.h"
#include "gts/micro_scheduler/patterns/ParallelReduce.h"
#include "gts/micro_scheduler/patterns/Partitioners.h"
#include "gts/micro_scheduler/patterns/Range1d.h"
 
using namespace gts;
 
namespace gts_examples {
 
//------------------------------------------------------------------------------
void fullParallelReduce()
{
    printf ("================\n");
    printf ("fullParallelReduce\n");
    printf ("================\n");
 
    // Init boilerplate
    WorkerPool workerPool;
    bool result = workerPool.initialize(1);
    GTS_ASSERT(result);
    MicroScheduler microScheduler;
    result = microScheduler.initialize(&workerPool);
    GTS_ASSERT(result);
 
    size_t const elementCount = 1 << 2;
 
    // Create the array to reduce.
    std::vector<uint32_t> vec(elementCount);
    for (size_t ii = 0; ii < elementCount; ++ii)
    {
        vec[ii] = uint32_t(ii);
    }
 
    // Make a parallel-reduce object for this scheduler. We do this because
    // there can be multiple scheduler objects.
    ParallelReduce parallelReduce(microScheduler);
 
    auto partitionerType = AdaptivePartitioner();
 
    uint32_t reduction = parallelReduce(
 
        // The 1D iterator range parallel-for will iterate over.
        Range1d<std::vector<uint32_t>::iterator>(vec.begin(), vec.end(), 1),
 
        // The function parallel-reduce will execute on each block of the range.
        // It returns the reduction of the block.
        [](Range1d<std::vector<uint32_t>::iterator>& range, void*, TaskContext const&) -> uint32_t
        {
            uint32_t result = 0;
            for (auto ii = range.begin(); ii != range.end(); ++ii)
            {
                result += *ii;
            }
            return result;
        },
 
        // The function that combines the block reductions.
        [](uint32_t const& lhs, uint32_t const& rhs, void*, TaskContext const&) -> uint32_t
        {
            return lhs + rhs;
        },
 
        // The initial value of the reduction.
        0,
 
        // The partitioner object.
        partitionerType);
 
    microScheduler.shutdown();
    workerPool.shutdown();
}
 
} // namespace gts_examples