pair_calculation.hpp

// this file does not have guard since it is used by other headers

template<int nbod>
GENERIC int first ( int ij ){
        int i = nbod - 1 - ij / (nbod/2);
        int j = ij % (nbod/2);
        if (j < i) 
                return i;
        else 
                return nbod - 1 - i - nbod%2 + 1;
}

template<int nbod>
GENERIC int second ( int ij ){
        int i = nbod - 1 - ij / (nbod/2);
        int j = ij % (nbod/2);
        if (j < i) 
                return j;
        else 
                return nbod - 1 - j - nbod%2;
}