do i=iphid_start,iphid_end
if (itype(i-2).eq.ntyp1 .or. itype(i-1).eq.ntyp1
& .or. itype(i).eq.ntyp1 .or. itype(i+1).eq.ntyp1) cycle
do i=iphid_start,iphid_end
if (itype(i-2).eq.ntyp1 .or. itype(i-1).eq.ntyp1
& .or. itype(i).eq.ntyp1 .or. itype(i+1).eq.ntyp1) cycle