OLattice<T>& d = const_cast<OSubLattice<T>&>(dd).field(); const Subset& s = dd.subset();
Seed seed; Seed skewed_seed;
void random(const OSubLattice<T>& dd){  OLattice<T>& d = const_cast<OSubLattice<T>&>(dd).field();  const Subset& s = dd.subset();  random(d,s);}