improved commentary
improved commentary


Former-commit-id: f435c9e40ab261a433429dacfcabd23b936ae7dc [formerly ebd2d8be316cb4309f3079e8fda254c0092123f1]
Former-commit-id: 8c8ac8b1ec08d57f0f1eda251f40d468f2620d86
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine