Scaffold of MO::Basis::LCAO#shells
RuPHY::Math::Matrix#diagonal_elements
Define all_be_within matcher
Spec for BasisSet::LCAO::Gaussian#shells
Initialize shells in MO::Basis::LCAO
Fix rspec label
Implement Mo::Basis::LCAO#shells
Specs for MO::Basis::LCAO#overlap
Define MO::Basis::LCAO#aos
Implement MO::Basis::LCAO#overlap
Implement AO::Gaussian::Contracted#overlap
Fix RuPHY::Math::Matrix
Delete obsolete workaround about Enumerator
Delete obsolete workaround about ::Matrix.each :diagonal
Additional spec for MO::Basis::LCAO#overlap
Workaround for undefined Matrix#symmetric?
Refactor spec
Use backports gem also on 1.9.2
Normalize AO::Gaussian::Contracted#overlap
Spec for off diagonal element of overlap matrix