Function sequant::antisymm::spin_sum

• Defined in File antisymmetrizer.cpp

Function Documentation

ExprPtr sequant::antisymm::spin_sum(std::vector<Index> original_upper, std::vector<Index> original_lower, ExprPtr expression, bool singlet_state)

not a general spin-summing procedure, implementation for a known singlet state for the prefactor rules to apply.

Parameters:

• original_upper – an antisymm_element object strictly so the original ordering of the indices is known

• original_lower – bool singlet_state? the looping rules and contraction prefactors are a direct result of the singlet state approximation to densities.