refactor: Remove Tesla conversion in estimateTrackParamsFromSeed (#…

…3835)

Currently we convert the magnetic field to Tesla and then convert back to length units. This can be avoided by using our native units which are the following
```c++
/// Magnetic field, native unit (eV*s)/(e*m²)
/// @note Depends on speed of light in SI units
constexpr double T = 0.000299792458;  // = eV * s / (e * m2);
```

Core/include/Acts/Seeding/EstimateTrackParamsFromSeed.hpp

@@ -64,15 +64,15 @@ std::optional<BoundVector> estimateTrackParamsFromSeed(
   }
 
   // Convert bField to Tesla
-  ActsScalar bFieldInTesla = bField.norm() / UnitConstants::T;
-  ActsScalar bFieldMinInTesla = bFieldMin / UnitConstants::T;
+  ActsScalar bFieldStrength = bField.norm();
   // Check if magnetic field is too small
-  if (bFieldInTesla < bFieldMinInTesla) {
+  if (bFieldStrength < bFieldMin) {
     // @todo shall we use straight-line estimation and use default q/pt in such
     // case?
-    ACTS_WARNING("The magnetic field at the bottom space point: B = "
-                 << bFieldInTesla << " T is smaller than |B|_min = "
-                 << bFieldMinInTesla << " T. Estimation is not performed.");
+    ACTS_WARNING(
+        "The magnetic field at the bottom space point: B = "
+        << bFieldStrength / UnitConstants::T << " T is smaller than |B|_min = "
+        << bFieldMin / UnitConstants::T << " T. Estimation is not performed.");
     return std::nullopt;
   }
 
@@ -142,7 +142,7 @@ std::optional<BoundVector> estimateTrackParamsFromSeed(
   int sign = ia > 0 ? -1 : 1;
   const ActsScalar R = circleCenter.norm();
   ActsScalar invTanTheta =
-      local2.z() / (2.f * R * std::asin(local2.head<2>().norm() / (2.f * R)));
+      local2.z() / (2 * R * std::asin(local2.head<2>().norm() / (2 * R)));
   // The momentum direction in the new frame (the center of the circle has the
   // coordinate (-1.*A/(2*B), 1./(2*B)))
   ActsScalar A = -circleCenter(0) / circleCenter(1);
@@ -174,7 +174,7 @@ std::optional<BoundVector> estimateTrackParamsFromSeed(
 
   // The estimated q/pt in [GeV/c]^-1 (note that the pt is the projection of
   // momentum on the transverse plane of the new frame)
-  ActsScalar qOverPt = sign * (UnitConstants::m) / (0.3 * bFieldInTesla * R);
+  ActsScalar qOverPt = sign / (bFieldStrength * R);
   // The estimated q/p in [GeV/c]^-1
   params[eBoundQOverP] = qOverPt / fastHypot(1., invTanTheta);
 

Examples/Python/tests/root_file_hashes.txt

@@ -3,16 +3,16 @@ test_fatras__particles_simulation.root: bc970873fef0c2efd86ed5413623802353d2cd04
 test_fatras__hits.root: 6e4beb045fa1712c4d14c280ba33c3fa13e4aff9de88d55c3e32f62ad226f724
 test_geant4__particles_simulation.root: 49926c71a9b54e13aa1cc7596d3302baf3c87d8e2c1d0267cb4523f6abdc0ac2
 test_geant4__hits.root: 4c9e704a75f47ed2e61652679a1d6f18fa4d9cf53faa8f8f5bbf7995634207aa
-test_seeding__estimatedparams.root: 69c0e268f9025a0991a212ea2a7f26f53112fecf614b475605bd1cb08415ba56
+test_seeding__estimatedparams.root: 6759004f945cabe03098c94b3eea7e3323acd9f37edfa71641797007336643c8
 test_seeding__performance_seeding.root: 992f9c611d30dde0d3f3ab676bab19ada61ab6a4442828e27b65ec5e5b7a2880
 test_seeding__particles.root: c423bc666df3674f1a1140dec68ea13f44173232b8057e8a02572aee4f3e7d5b
 test_seeding__particles_simulation.root: f937a4cc474e80cfbb6eac4384e42e9c5c7ac981fcd6870d624cc898d1a0c006
-test_hashing_seeding__estimatedparams.root: 8daa3f04342c265f32f1608ccc921ab0041686a6280b956f811638ad4328330e
-test_seeding_orthogonal__estimatedparams.root: ca5896ec325daf5c8012291bc454269c61c32fe3d7e33bd1fa3b812826930299
+test_hashing_seeding__estimatedparams.root: 6b52f27b2feac2fa46a8ed52abacfe6dc8e6319f86e031cdc2f9ba28a0393cb2
+test_seeding_orthogonal__estimatedparams.root: 6cb69ee239e11ff112dd50c2bcfe945a6f7b00e43e13b2cba4e08f1bfcf6a583
 test_seeding_orthogonal__performance_seeding.root: 60fbedcf5cb2b37cd8e526251940564432890d3a159d231ed819e915a904682c
 test_seeding_orthogonal__particles.root: c423bc666df3674f1a1140dec68ea13f44173232b8057e8a02572aee4f3e7d5b
 test_seeding_orthogonal__particles_simulation.root: f937a4cc474e80cfbb6eac4384e42e9c5c7ac981fcd6870d624cc898d1a0c006
-test_itk_seeding__estimatedparams.root: 1cc05f9f2aefb5f71a85b31e97bc4e5845fedfcef6c53199495a6340c6b6210b
+test_itk_seeding__estimatedparams.root: fc042037f12a434f2236df7d225b8ca24209b6910f04a4496ae3a06516a6ff8c
 test_itk_seeding__performance_seeding.root: 78ebda54cd0f026ba4b7f316724ffd946de56a932735914baf1b7bba9505c29d
 test_itk_seeding__particles.root: 907ff693262c0db14b12c74b16586cb20d79caf5f03f93b178943e41ed35a1b6
 test_itk_seeding__particles_simulation.root: ef0246069aa697019f28a8b270a68de95312cae5f2f2c74848566c3ce4f70363
@@ -33,19 +33,19 @@ test_digitization_example_input[smeared]__particles.root: 669d0304eb8bcf244aa627
 test_digitization_example_input[smeared]__measurements.root: 243c2f69b7b0db9dbeaa7494d4ea0f3dd1691dc90f16e10df6c0491ff4dc7d62
 test_digitization_example_input[geometric]__particles.root: 669d0304eb8bcf244aa627809a117944e5e3b994fdfcfb8710f2b9a8f9a62d3b
 test_digitization_example_input[geometric]__measurements.root: 63ec81635979058fb8976f94455bf490cf92b7b142c4a05cc39de6225f5de2fb
-test_ckf_tracks_example[generic-full_seeding]__trackstates_ckf.root: 7c48ec32a2cb1723416a9791a8067ef09825fcf71a6cf561c1f6d2ab9dc1c1ad
-test_ckf_tracks_example[generic-full_seeding]__tracksummary_ckf.root: e6b9e539998ba007e9b7d2c8d9d022c47726a39e8ab9b1724c52b1d78234be03
+test_ckf_tracks_example[generic-full_seeding]__trackstates_ckf.root: ec6487dfca5f944cfacfef903eb4b9a97f8f6a668d07f77d0c3ec45c68054824
+test_ckf_tracks_example[generic-full_seeding]__tracksummary_ckf.root: 84085bcc63562cfb1b4c70d2665bf06938ac559bb40c2b01c076e1d8b5c7b43b
 test_ckf_tracks_example[generic-full_seeding]__performance_seeding_trees.root: 0e0676ffafdb27112fbda50d1cf627859fa745760f98073261dcf6db3f2f991e
-test_ckf_tracks_example[generic-truth_estimated]__trackstates_ckf.root: df730fd00a7e6a0941f5f94c07ea9cffdb763853272d284d25bec0eb2072bb2e
-test_ckf_tracks_example[generic-truth_estimated]__tracksummary_ckf.root: 417f7326e1e1bb4519f1378145ac733bdda6653eb9871fd69e455e0269d996a6
+test_ckf_tracks_example[generic-truth_estimated]__trackstates_ckf.root: 8e15cceeef4b115708596702988925b7506d39e0531dc5534636ec411a9b4ca2
+test_ckf_tracks_example[generic-truth_estimated]__tracksummary_ckf.root: 8e0116c656e1cc67446d54a5205c4a3e2f4c1fc90fa551bb608c881877dfa0ab
 test_ckf_tracks_example[generic-truth_estimated]__performance_seeding.root: 1facb05c066221f6361b61f015cdf0918e94d9f3fce2269ec7b6a4dffeb2bc7e
 test_ckf_tracks_example[generic-truth_smeared]__trackstates_ckf.root: 82a6744980553e6274df78eea15f0dec22676b1c04e14afc3828bff9bbf5e1b1
 test_ckf_tracks_example[generic-truth_smeared]__tracksummary_ckf.root: 06d6ae1d05cb611b19df3c59531997c9b0108f5ef6027d76c4827bd2d9edb921
-test_ckf_tracks_example[odd-full_seeding]__trackstates_ckf.root: 0fb43661cc3a7973c28940a283dc168ceb13bc60badf1f520096edaa5982a039
-test_ckf_tracks_example[odd-full_seeding]__tracksummary_ckf.root: c2e029e462d4ca77df2c7f8963093da43be66c8279ca2cc9aee8c0bc35259eec
+test_ckf_tracks_example[odd-full_seeding]__trackstates_ckf.root: 17c48c5a61b1a5495d91336cdf06f9c24e50d81349c1f31d7c70ffff5810a376
+test_ckf_tracks_example[odd-full_seeding]__tracksummary_ckf.root: b5805e54030ab8ac80a8c0a764700c65433dc659783fc8ff3b2c96e512a1d045
 test_ckf_tracks_example[odd-full_seeding]__performance_seeding_trees.root: 43c58577aafe07645e5660c4f43904efadf91d8cda45c5c04c248bbe0f59814f
-test_ckf_tracks_example[odd-truth_estimated]__trackstates_ckf.root: 39ac67c47f371c576d7094bca987a04e0315bd286dc79503a63a5f568b58ac97
-test_ckf_tracks_example[odd-truth_estimated]__tracksummary_ckf.root: 59e2c75e9524653a80a9fd62fe99e958f73f80aa09240dcbb4ea469372e4811d
+test_ckf_tracks_example[odd-truth_estimated]__trackstates_ckf.root: 86be5a086d2a87dfde9320bb880bd0788d733ea9727cb5ee6dc0282ec4be39f4
+test_ckf_tracks_example[odd-truth_estimated]__tracksummary_ckf.root: ffce6a73f16986cb3f0386d4a8c1e0ff6f0b4130b9bb12d1af0eb905d000e3e9
 test_ckf_tracks_example[odd-truth_estimated]__performance_seeding.root: 1a36b7017e59f1c08602ef3c2cb0483c51df248f112e3780c66594110719c575
 test_ckf_tracks_example[odd-truth_smeared]__trackstates_ckf.root: 35a65e15a6f479f628a96f56ee78e1ac371d71a686ee0c974944d681499fe6bd
 test_ckf_tracks_example[odd-truth_smeared]__tracksummary_ckf.root: 3e257de624674fa9a19dcc72598c78c29a52633821acaa56dc2aa39a1395f1b5