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network sorting for short arrays

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This commit is contained in:
Jiri Pittner 2024-04-03 16:17:32 +02:00
parent 2f48effddc
commit c67549a296
2 changed files with 121 additions and 1 deletions
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113
qsort.h
View File

@ -280,6 +280,119 @@ void myheapsort(INDEX n, DATA *ra,int typ=1)
}
//network up-sorting templates
//more elegant would be a double template with N and partial specialization, but this is not allowed in current C++ for non-member functions
//
#define CONDSWAP(i,j) if(data[i]>data[j]) {T tmp=data[i]; data[i]=data[j]; data[j]=tmp; parity^=1;}
template<typename T>
inline int netsort_0(T *data) {return 0;}
template<typename T>
inline int netsort_1(T *data) {return 0;}
template<typename T>
inline int netsort_2(T *data)
{
int parity=0;
CONDSWAP(0,1);
return parity;
}
template<typename T>
inline int netsort_3(T *data)
{
int parity=0;
CONDSWAP(0,2);
CONDSWAP(0,1);
CONDSWAP(1,2);
return parity;
}
template<typename T>
inline int netsort_4(T *data)
{
int parity=0;
CONDSWAP(0,2);
CONDSWAP(1,3);
CONDSWAP(0,1);
CONDSWAP(2,3);
CONDSWAP(1,2);
return parity;
}
template<typename T>
inline int netsort_5(T *data)
{
int parity=0;
CONDSWAP(0,3);
CONDSWAP(1,4);
CONDSWAP(0,2);
CONDSWAP(1,3);
CONDSWAP(0,1);
CONDSWAP(2,4);
CONDSWAP(1,2);
CONDSWAP(3,4);
CONDSWAP(2,3);
return parity;
}
template<typename T>
inline int netsort_6(T *data)
{
int parity=0;
CONDSWAP(0,5);
CONDSWAP(1,3);
CONDSWAP(2,4);
CONDSWAP(1,2);
CONDSWAP(3,4);
CONDSWAP(0,3);
CONDSWAP(2,5);
CONDSWAP(0,1);
CONDSWAP(2,3);
CONDSWAP(4,5);
CONDSWAP(1,2);
CONDSWAP(3,4);
return parity;
}
#undef CONDSWAP
template<typename T>
int netsort(const int n, T *data)
{
if(n<0) laerror("negative n in netsort");
switch(n)
{
case 0:
case 1:
return 0;
break;
case 2:
return netsort_2(data);
break;
case 3:
return netsort_3(data);
break;
case 4:
return netsort_4(data);
break;
case 5:
return netsort_5(data);
break;
case 6:
return netsort_6(data);
break;
default:
return ptrqsortup<T,int>(data,data+n-1);
break;
}
return 0;
}
}//namespace
#endif

9
t.cc
View File

@ -3176,12 +3176,19 @@ for(int l=1; l<k; ++l)
cout <<count<<" "<<binom(n,4)<<endl;
}
if(1)
if(0)
{
int d,n;
cin>>d>>n;
cout <<simplicial(d,n)<<" "<<binom(n+d-1,d)<<endl;
}
if(1)
{
NRVec<int> d({6,2,1,4,3,5});
d.copyonwrite();
netsort(d.size(),&d[0]);
cout <<d;
}
}