tensor( this_type const& expr, Geo_t const& geom, Basis_i_t const& fev ) : M_tensor_expr( expr.expression(), geom, fev ), M_inv( vf::detail::ExtractGm<Geo_t>::get( geom )->nPoints() ) { }
tensor( this_type const& expr, Geo_t const& geom ) : M_tensor_expr( expr.expression(), geom ) { }
tensor( this_type const& expr, Geo_t const& geom, Basis_i_t const& fev ) : M_tensor_expr( expr.expression(), geom, fev ) { }