v20.0.0

⚠️ Breaking changes

• The template parameters of CombinatorialKalmanFilter, KalmanFitter and GaussianSumFitter changes to

  template <typename propagator_t, typename traj_t>
  class CombinatorialKalmanFilter;
  template <typename propagator_t, typename traj_t>
  class KalmanFitter;
  template <typename propagator_t, typename traj_t,
         typename bethe_heitler_approx_t = detail::BetheHeitlerApprox<6, 5>>
  struct GaussianSumFitter;

  Related classes (options, extensions, result) also change, gaining a traj_t template parameter. This parameter is the type of the memory backend. See #1262 (5cbcbf0) (@paulgessinger)

• Build DD4hep geometry from hierarchy, use VariantParameters
  This changes the DD4hep integration model. Instead of the DD4hep factory code having to depend on ACTS or the ActsDD4hep glue lib, they now use a mechanism we merged into DD4hep (as of 1.21): MapStringVariantStruct, which is wrapped into a detector element extension as VariantParameters. The minimum DD4hep version is increased to 1.21. See #1257(e72db5d) (@paulgessinger)

---

Documentation

• Description of ODD full chain example (#1401) (b1cce93) (@andiwand)
• Fix sphinx-level warnings (#1430) (0c12cd5) (@paulgessinger)
• Use DEVNULL instead of PIPE in apidoc subprocess (#1431) (d9117a0) (@paulgessinger)
• Adding acts project page (#1392) (e3a0da7) (@asalzburger)
• Add docs clean target to cmake (#1393) (968993e) (@paulgessinger)
• Minor corrections. followup to PR #1405 (#1407) (ba1e563) (@AJPfleger)
• Minor corrections (#1405) (df70711) (@andiwand)
• Propagation (#1396) (5cef357) (@benjaminhuth)
• Restructure docs tree (#1387) (50d5f44) (@andiwand)
• Correct affiliation in CITATION.cff (#1390) (d03a306) (@benjaminhuth)
• Spelling, delete unused figures, beautify (#1353) (85eb654) (@AJPfleger)

Feature

• Use Range1D<> class for extent (#1424) (81e9573) (@asalzburger)
• Enable Delegates to conveniently use stateful lambdas (#1410) (f673126) (@benjaminhuth)
• MultiTrajectory backends (#1262) (5cbcbf0) (@paulgessinger)
• CI checks for ITk seeding example (#1352) (1ae80fb) (@LuisFelipeCoelho)

Ci

• Bump codecov action to v3 (#1427) (f89c7c5) (@paulgessinger)
• Move Analysis job from required pattern to explicit name (#1411) (123afb6) (@paulgessinger)
• Fix path-ignore for docs (#1408) (0352563) (@paulgessinger)
• Do not run analysis jobs on docs-only changes (#1400) (040c1fa) (@paulgessinger)
• Docs job always runs (#1391) (daae3c2) (@paulgessinger)
• Fix sentinel yml (#1389) (9ce84b8) (@paulgessinger)
• Do not run build jobs on docs-only changes (#1388) (fd29182) (@paulgessinger)
• Cleaned up the workflow files a little. (#1384) (a543587) (@wermos)
• Automatically remove automerge label when PRs are closed (#1372) (f3d23e0) (@paulgessinger)
• Trigger CI also on PRs to develop/* branches (#1367) (f956eb3) (@paulgessinger)
• Set up backport action that reacts to labels (#1365) (aab7f0c) (@paulgessinger)

Refactor

• Improve ActsPythonBindings tracing (#1425) (b945729) (@timadye)
• Build DD4hep geometry from hierarchy, use VariantParameters (#1257) (e72db5d) (@paulgessinger)

Fix

• RootBFieldWriter incorrect output (#1381) (d6d2223) (@timadye)
• Change typeid check to dynamic_cast (#1409) (fdc6075) (@asalzburger)
• Full chain vertexing (#1299) (884d342) (@andiwand)
• Multi-Stepper stepping error in multiple components + refactoring (#1339) (1b973d5) (@benjaminhuth)
• Any direction for helical track linearizer (#1363) (8639c37) (@andiwand)
• Initialising world in GdmlDetectorConstruction (#1371) (511528b) (@asalzburger)

Chore

• Clang tidy check uninitialized members (#1373) (5f7ffcb) (@andiwand)
• Clang-tidy modernize-use-nullptr (#1358) (789ce69) (@paulgessinger)