v21.0.0

Breaking

• std::unique_ptr to std::optional in Acts::PropagatorResult (#1622) (ec15a62) (@benjaminhuth)
• Acts::MultiTrajectory measurement access methods change: (5b802fc) (@paulgessinger)
• Put GSF in namespace Acts::Experimental (#1609) (f6f0e1f) (@benjaminhuth)
• Include file names are changed and so are the classes. Fix is trivial on client side, yet needs to be done in several places when migrating. (f8e756e) (@tboldagh)

Feature

• Add whiteboard aliases (#1588) (5addf02) (@andiwand)
• GX2F (Global Chi2 Fitter) | Gχ²F (#1580) (890eff9) (@AJPfleger)
• Examples restore vertexing track selector (#1644) (e1b8ebb) (@andiwand)
• Seed confirmation in orthogonal seed finder (#1611) (65ea889) (@LuisFelipeCoelho)
• Poor man's ambiguity resolution example (#1579) (08b9e91) (@andiwand)
• Skip SPs based on cotTheta sorting in orthogonal seeding (#1608) (20ac7b8) (@LuisFelipeCoelho)
• Helix cut calculated from duplets in orthogonal seeding (#1604) (b7b3e77) (@LuisFelipeCoelho)
• MultiTrajectory backends const version (#1496) (02e39a4) (@paulgessinger)
• DeltaZ cut in SeedFinderOrthogonal (#1601) (eef2627) (@LuisFelipeCoelho)
• Vertexing mu scan and CI job that creates it (#1595) (a3628bd) (@paulgessinger)
• Make whiteboard suggest names on mismatch (#1597) (e2a8df8) (@benjaminhuth)
• VectorMultiTrajectory memory statistics (#1511) (2e4eb38) (@paulgessinger)
• Break loop over triplets in seed finder (#1576) (f1489ce) (@LuisFelipeCoelho)

Refactor

• DD4hep detector access (#1637) (75f9338) (@andiwand)
• Std::unique_ptr to std::optional in Acts::PropagatorResult (#1622) (ec15a62) (@benjaminhuth)
• Configurable variables in seed confirmation (#1639) (dad2af9) (@LuisFelipeCoelho)
• MTJ stores measurement as jagged vector (#1512) (5b802fc) (@paulgessinger)
• Time optimization for calculation of min and max r variable range (#1558) (0fedd65) (@LuisFelipeCoelho)
• Put GSF in namespace Acts::Experimental (#1609) (f6f0e1f) (@benjaminhuth)
• Change loglevel for MultiTrajectory memory statistics from info to debug (#1623) (1d7e9b2) (@benjaminhuth)
• Remove dependency on Boost::program_options from Algorithms/Writers/Readers (#1610) (5d65b73) (@benjaminhuth)
• Restructure track fitting functions (#1617) (ca3320f) (@benjaminhuth)
• Rearrange seed confirmation to avoid unnecessary checks (#1577) (f20738e) (@LuisFelipeCoelho)
• Rename Seedfinder to SeedFinder - classes and files (#1575) (f8e756e) (@tboldagh)
• Add macro to simplify algorithm binding (#1510) (eaa9d5f) (@benjaminhuth)
• Add early stop mechanism for GSF forward pass (#1542) (5592ff2) (@benjaminhuth)
• Move rRangeSPExtent to BinnedSPGroup (#1582) (e9e0036) (@LuisFelipeCoelho)
• Remove workarounds in GSF for result initialization (#1593) (7261df8) (@benjaminhuth)
• Improve logging, configuration and doc of G4 surface mapping (#1589) (94f1e07) (@benjaminhuth)

Fix

• ITk full chain (#1642) (c780eb2) (@andiwand)
• Enable examples if python examples are enabled (#1625) (4ecb048) (@andiwand)
• TrackSelector eta vs theta (#1615) (b518cb2) (@andiwand)
• Orthogonal seeding configuration with Python bindings (#1605) (4b9d9c4) (@LuisFelipeCoelho)
• Restore compatibility of GSF with gcc-8 (#1600) (0273fb8) (@benjaminhuth)
• Require Python version ≥3.8 for examples (#1602) (b18804a) (@stephenswat)
• Non finite weight handling in GSF (#1591) (f0b4688) (@benjaminhuth)

CI

• Update doxygen URL to sourceforge (#1635) (5c07814) (@paulgessinger)
• Bump setup-python (#1618) (f2619c1) (@paulgessinger)
• Update physmon report to handle missing artifact (654491d) (@paulgessinger)
• Bump histcmp to v0.5.2 (0237412) (@paulgessinger)
• Physmon create dir before saving PR number (d377c60) (@paulgessinger)
• Add reporting to physmon (#1612) (e3947c1) (@paulgessinger)
• Update macos deps (#1606) (66e0b95) (@andiwand)

Chore

• Auto cancel (#1619) (9d65e7f) (@andiwand)
• Update physmon template (#1614) (76bedbf) (@paulgessinger)

Documentation

• Add Track Fitting (#1398) (4ddf9e8) (@AJPfleger)
• Fix caption of figure in seeding documentation (#1598) (9c780d4) (@LuisFelipeCoelho)
• Updates to the seeding documentation (#1476) (ecf90a3) (@LuisFelipeCoelho)