粒子与网格归属问题

李东岳

感谢各位大佬，太神奇了。目前我在想或许DynamicList或者hash table是个好出发点

李东岳

我现在用的最笨的方法弄得：

网格遍历
粒子遍历
如果粒子恰好在网格内，就把label存储在当前网格的DynamicList

        forAll(U_, cell)                                         
        {
            DynamicList<label> pL(0);
                                                                 
            scalar pN = 0;
            forAllConstIter(typename MomentumCloud<CloudType>, *this, iter)
            {                                                    
                const parcelType& p = iter();                    
                if (p.cell() == cell)                            
                {                                                
                    pN += 1;                                     
                    pL.append(p.origId());
                }                                                
            }
            
            if (pN != 0)                                         
            {
                Info<< "Cell[" << cell << "] has " << pN << " particles, "
                    << "particle label is " << pL << nl;         
            }
        }

输出结果还可以：

Cell[2295] has 2 particles, particle label is 2(20 21)
Cell[2297] has 2 particles, particle label is 2(4 7)
Cell[2298] has 1 particles, particle label is 1(3)
Cell[2340] has 3 particles, particle label is 3(17 18 19)
Cell[2341] has 5 particles, particle label is 5(11 13 14 15 16)
Cell[2342] has 4 particles, particle label is 4(5 6 8 9)
Cell[2343] has 1 particles, particle label is 1(1)
Cell[2386] has 1 particles, particle label is 1(12)
Cell[2387] has 1 particles, particle label is 1(10)
Cell[2388] has 2 particles, particle label is 2(0 2)

但是这里面遍历网格+遍历粒子。肯定是要慢。

马乔

@李东岳这么写呢？

            List<DynamicList<label>> pL(U_.size());
            forAllConstIter(typename MomentumCloud<CloudType>, *this, iter)
            {                                                    
                     const parcelType& p = iter();                                              
                    pL[p.cell()].append(p.origId());                                           
            }

或者

std::Multimap<label,label> Lp;
forAllConstIter(typename MomentumCloud<CloudType>, *this, iter)
{
     const parcelType& p = iter();  
     Lp.insert(std::pair<label,label>(p.cell(), p.origId()));
}

都是我云的

李东岳

@马乔

            List<DynamicList<label>> pL(U_.size());
            forAllConstIter(typename MomentumCloud<CloudType>, *this, iter)
            {                                                    
                     const parcelType& p = iter();                                              
                    pL[p.cell()].append(p.origId());                                           
            }

这种方法不需要遍历两次。类似一种DynamicListField。不过有很多元素是空的。不过比我的方法要快。挺好。多谢大佬

马乔

@同学博你这么操作map是对的，我开想的是查找key

同学博

@马乔

TM

这段用来统计网格单元内粒子个数的代码，编译的路径是什么，求东岳老师指导

CFD中文网

粒子与网格归属问题