Expand description
The materialized hierarchy.
Integer-keyed compressed sparse row adjacency for a code system’s is-a
hierarchy and each typed relationship, plus roaring transitive-closure
bitmaps. Subsumption is a bitmap membership test, and the ECL evaluator
compiles constraints to set algebra over these bitmaps. The graph is built
offline by a loader and served read-only; no request traverses edges live.
No FHIR or SNOMED specification governs the layout: our own design
(docs/architecture.md decisions 1 and 3).
Modules§
- attributes
- The attribute relationships of an edition.
- closure
- The transitive closure of the is-a hierarchy.
- csr
- Compressed sparse row adjacency.
- identifiers
- The alternate identifiers of an edition: a code of another scheme
(
LOINC54486-6) for a concept, from the RF2 identifier file, so an ECLscheme#codefocus resolves to the concept. - members
- Reference set memberships: for every reference set of an edition, the bitmap of the concepts that are its active members.
- ordinal
- Dense ordinals: the graph’s own keys.
- persist
- A versioned binary layout for the graph, for the offline build to store.
- refsets
- The active members of every concept-referencing reference set, with their fields.
- relations
- Typed adjacency: every edge carries a relationship type, and both directions are materialized.
- subsumption
- Subsumption over the closure, in the vocabulary FHIR
$subsumesreturns.