sortedPairs.hpp

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/*------------------------------- phasicFlow ---------------------------------
      O        C enter of
     O O       E ngineering and
    O   O      M ultiscale modeling of
   OOOOOOO     F luid flow       
------------------------------------------------------------------------------
  Copyright (C): www.cemf.ir
  email: hamid.r.norouzi AT gmail.com
------------------------------------------------------------------------------  
Licence:
  This file is part of phasicFlow code. It is a free software for simulating 
  granular and multiphase flows. You can redistribute it and/or modify it under
  the terms of GNU General Public License v3 or any other later versions. 
 
  phasicFlow is distributed to help others in their research in the field of 
  granular and multiphase flows, but WITHOUT ANY WARRANTY; without even the
  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 
-----------------------------------------------------------------------------*/
 
 
#ifndef __sortedPairs_hpp__
#define __sortedPairs_hpp__
 
#include "unsortedPairs.hpp"
#include "KokkosUtilities.hpp"
 
namespace pFlow
{
 
 
template<typename executionSpace, typename idType>
class sortedPairs
:
    public unsortedPairs<executionSpace, idType>
{
public:
 
    using UnsortedPairs = unsortedPairs<executionSpace,idType>;
 
    using IdType            = typename UnsortedPairs::IdType;
 
    using ExecutionSpace    = typename UnsortedPairs::ExecutionSpace;
 
    using memory_space      = typename ExecutionSpace::memory_space;
 
    using PairType          = typename UnsortedPairs::PairType;
 
    using ContainerType     = typename UnsortedPairs::ContainerType;
 
    struct pairAccessor
    {
        using PairType = typename sortedPairs::PairType;
 
        int32 size_;
 
        ViewType1D<PairType,ExecutionSpace> sortedParis_;
 
        INLINE_FUNCTION_HD
        int32 size()const { return size_; }
 
        INLINE_FUNCTION_HD
        int32 loopCount()const { return size_; }
 
        INLINE_FUNCTION_HD
        bool isValid(int32 i)const { return i<size_; }
 
        INLINE_FUNCTION_HD
        PairType getPair(int i)const {  return sortedParis_[i]; }
 
        INLINE_FUNCTION_HD
        bool getPair(int32 i, PairType& pair)const {
            if(i<size_) {
                pair = sortedParis_[i];
                return true;
            }
            return false;
        }
    };
 
    class TagFillFlag{};
 
    class TagFillPairs{};
 
protected:
 
    int32           size_ = 0;
 
    ViewType1D<int32,ExecutionSpace>        flags_;
 
    ViewType1D<PairType,ExecutionSpace>     sortedPairs_;
 
    using rpFillFlag = Kokkos::RangePolicy<
        ExecutionSpace,
        Kokkos::Schedule<Kokkos::Static>,
        Kokkos::IndexType<int32>,
        TagFillFlag >;
 
    using rpFillPairs = Kokkos::RangePolicy<
        ExecutionSpace,
        Kokkos::Schedule<Kokkos::Static>,
        Kokkos::IndexType<int32>,
        TagFillPairs>;
    
public:
    
    // - type info
    TypeInfoNV("sortedPairs");
 
 
    // constructors
    sortedPairs(int32 initialSize =1)
    :
        UnsortedPairs(initialSize),
        flags_("flags_",UnsortedPairs::capacity()+1),
        sortedPairs_("sortedPairs_",UnsortedPairs::capacity())
    {}
 
    
    bool beforeBroadSearch()
    {
        this->clear();
        return true;
    }
 
    bool afterBroadSearch()
    {
        prepareSorted();
        return true;
    }
 
    // - Device call
    //   return the pair at index idx
    //   perform no check for size and existance
    INLINE_FUNCTION_HD
    PairType getPair(int32 idx)const
    {
        return sortedPairs_[idx];
    }
 
    // - Device/host call
    //   return the pair at index idx
    INLINE_FUNCTION_HD
    bool getPair(int32 idx, PairType& p)const
    {
        if(isValid(idx))
        {
            p = getPair(idx);
            return true;
        }
        else
        {
            return false;
        }
    }
 
    INLINE_FUNCTION_HD
    bool isValid(int32 idx)const
    {
        return idx < size_; 
    }
 
 
    //use this when the value of size_ is updated
    INLINE_FUNCTION_H
    int32 size()const
    {
        return size_;
    }
 
    int32 loopCount()const
    {
        return size_;
    }
 
    pairAccessor getPairs()const
    {
        return {size_, sortedPairs_};
    }
 
    INLINE_FUNCTION_H
    void clear()
    {
        UnsortedPairs::clear();
        size_ = 0;
    }
 
    void prepareSorted()
    {
        // first check the size of flags_ 
        int32 capacity = UnsortedPairs::capacity();
 
        if( capacity+1 > flags_.size() )
        {
            reallocNoInit(flags_, capacity+1);
        }
 
        // fill the flags
        Kokkos::parallel_for(
            "contactPairsSorted::fillFlag",
            rpFillFlag(0,capacity+1),
            *this);
        Kokkos::fence();
        
 
        // inclusive scan on flags_
        exclusiveScan(flags_, 0, capacity+1,flags_,0);
 
        Kokkos::fence(); // Kokkos's scan is blocking I guess. So, this could be removed. 
        
        // get the last value of flags_ to obtain the size of sortedPairs_      
        getNth(size_, flags_, capacity);
        
        if(size_ == 0 )return;
 
        // resize sortedPairs_ if necessary;
        if( size_>sortedPairs_.size() )
        {
            // get more space to prevent reallocations in next iterations
            int32 len = size_*1.1+1; 
            reallocNoInit(sortedPairs_, len);
        }
        
        Kokkos::parallel_for(
            "contactPairsSorted::fillPairs",
            rpFillPairs(0,this->capacity()),
            *this);
        Kokkos::fence();
 
        // - sort paris based on the first and second
        sort(sortedPairs_, 0, size_ );
        
 
    }
 
    INLINE_FUNCTION_HD
    void operator()(TagFillFlag, int32 i)const
    {
        if(this->container_.valid_at(i) )
            flags_[i] = 1;
        else
            flags_[i] = 0;
    }
 
    INLINE_FUNCTION_HD
    void operator()(TagFillPairs, int32 i)const
    {
        auto fi = flags_[i];
        if(fi!=flags_[i+1])
            sortedPairs_[fi] = this->container_.key_at(i);
    }   
 
};
 
}
 
#endif //__sortedPairs_hpp__