da1->alloc(dan/2,1); da2->alloc(dan/2,1);
std::copy(da->getConstPointer(), da->getConstPointer()+dan/2, da1->getPointer());
std::copy(da->getConstPointer()+dan/2, da->getConstPointer()+dan, da2->getPointer());
da1->alloc(dan/2,1); da2->alloc(dan/2,1);
std::copy(da->getConstPointer(), da->getConstPointer()+dan/2, da1->getPointer());
std::copy(da->getConstPointer()+dan/2, da->getConstPointer()+dan, da2->getPointer());