Currently, it is not possible to construct an Einstein reduction expression without copying the operands. Most of these copies are small/lightweight (never arrays, only array_refs), but operands that are functions/lambdas may be expensive to copy or not copyable at all.
Currently, it is not possible to construct an Einstein reduction expression without copying the operands. Most of these copies are small/lightweight (never arrays, only array_refs), but operands that are functions/lambdas may be expensive to copy or not copyable at all.