Function sequant::mbpt::bernoulli::detail::N_part

• Defined in File bernoulli.cpp

Function Documentation

ExprPtr sequant::mbpt::bernoulli::detail::N_part(const ExprPtr &expr, std::size_t cutoff, std::size_t min_rank)

Block-resolved N part (O_N of 10.1063/1.5030344): the terms whose single residual NormalOperator is a pure excitation or pure de-excitation of rank in [min_rank, cutoff]. Applies expand_to_blocks first.

Parameters:

min_rank – lowest rank σ carries, so 2 when singles are skipped. Below it there is no amplitude and the condition V̄_N = 0 that justifies calling a term N does not hold.