fix: resurrect ActsScalar with float

[AJPfleger]

For some time, we had a rather random usage of ActsScalar instead of double. This generated mismatches child classes which made it impossible to compile the project.

This PR starts to reanimate ActsScalar. For the start we try only a minimal build of Core. We provide:

• a CI-job, that attempts the minimal build with ACTS_CUSTOM_SCALARTYPE=float, ignoring narrowing warnings
• fixes for Core, to enable a build

In following PRs, we should aim at also building the unit tests and examples until we can actually run the tests.

[AJPfleger]

@andiwand Could you maybe help me to adapt the SympyStepper? This is the only failing unit.

[ 53%] Building CXX object Core/CMakeFiles/ActsCore.dir/src/Propagator/SympyStepper.cpp.o
/__w/acts/acts/Core/src/Propagator/SympyStepper.cpp: In member function 'Acts::Result<double> Acts::SympyStepper::stepImpl(State&, Acts::Direction, double, double, std::size_t) const':
/__w/acts/acts/Core/src/Propagator/SympyStepper.cpp:151:12: error: no matching function for call to 'rk4(Eigen::PlainObjectBase<Eigen::Matrix<float, 3, 1> >::Scalar*, Eigen::PlainObjectBase<Eigen::Matrix<float, 3, 1> >::Scalar*, double&, double&, double&, double&, double&, Acts::SympyStepper::stepImpl(State&, Acts::Direction, double, double, std::size_t) const::<lambda(const double*)>&, double*, double, Eigen::MapBase<Eigen::Block<Eigen::Matrix<float, 8, 1, 0, 8, 1>, 3, 1, false>, 1>::ScalarWithConstIfNotLvalue*, Eigen::MapBase<Eigen::Block<Eigen::Matrix<float, 8, 1, 0, 8, 1>, 3, 1, false>, 1>::ScalarWithConstIfNotLvalue*, Eigen::MapBase<Eigen::Block<Eigen::Matrix<float, 8, 1, 0, 8, 1>, 1, 1, false>, 1>::ScalarWithConstIfNotLvalue*, Eigen::PlainObjectBase<Eigen::Matrix<float, 8, 1, 0, 8, 1> >::Scalar*, Eigen::PlainObjectBase<Eigen::Matrix<float, 8, 8, 0, 8, 8> >::Scalar*)'
  151 |         rk4(pos.data(), dir.data(), t, h, qop, m, p_abs, getB, &errorEstimate,
      |         ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  152 |             4 * stepTolerance, state.pars.template segment<3>(eFreePos0).data(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  153 |             state.pars.template segment<3>(eFreeDir0).data(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  154 |             state.pars.template segment<1>(eFreeTime).data(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  155 |             state.derivative.data(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~
  156 |             state.covTransport ? state.jacTransport.data() : nullptr);
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /__w/acts/acts/Core/src/Propagator/SympyStepper.cpp:17:
/__w/acts/acts/Core/src/Propagator/codegen/sympy_stepper_math.hpp:19:20: note: candidate: 'template<class T, class GetB> Acts::Result<bool> rk4(const T*, const T*, T, T, T, T, T, GetB, T*, T, T*, T*, T*, T*, T*)'
   19 | Acts::Result<bool> rk4(const T* p, const T* d, const T t, const T h,
      |                    ^~~
/__w/acts/acts/Core/src/Propagator/codegen/sympy_stepper_math.hpp:19:20: note:   template argument deduction/substitution failed:
/__w/acts/acts/Core/src/Propagator/SympyStepper.cpp:151:12: note:   deduced conflicting types for parameter 'T' ('float' and 'double')
  151 |         rk4(pos.data(), dir.data(), t, h, qop, m, p_abs, getB, &errorEstimate,
      |         ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  152 |             4 * stepTolerance, state.pars.template segment<3>(eFreePos0).data(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  153 |             state.pars.template segment<3>(eFreeDir0).data(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  154 |             state.pars.template segment<1>(eFreeTime).data(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  155 |             state.derivative.data(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~
  156 |             state.covTransport ? state.jacTransport.data() : nullptr);
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[andiwand]

@andiwand Could you maybe help me to adapt the SympyStepper? This is the only failing unit.

I think the hardcoded doubles are fighting here with the Vector3 floats. This should be fixable by putting ActsScalar on the offending variables.

On a general note: I wonder if we should rather get rid of ActsScalar because for CPUs it does not make a difference if you use double or float in my experience. I rather observed cases where floats make things worse because of conversions or other CPU black magic.

I think we should use the type which makes sense which is by default double and float in cases someone has a benchmark to proof it is more optimal or for memory reasons like for the material mapping.

[AJPfleger]

Thanks, I just read through the code generation and saw, that the relevant part is not generated by Sympy.

[github-actions]

📊: Physics performance monitoring for 508be93

Full contents

physmon summary

• ✅ Particles fatras
• ✅ Particles geant4
• ✅ Particles ttbar
• ✅ Vertices ttbar
• ✅ Truth tracking (KF)
• ✅ Truth tracking (GSF)
• ✅ Truth tracking (GX2F)
• ✅ Truth tracking (KF refit)
• ✅ Truth tracking (GSF refit)
• ✅ CKF | trackfinding | single muon | truth smeared seeding
• ✅ Track Summary CKF | trackfinding | single muon | truth smeared seeding
• ✅ Seeding trackfinding | single muon | truth estimated seeding
• ✅ CKF | trackfinding | single muon | truth estimated seeding
• ✅ Track Summary CKF | trackfinding | single muon | truth estimated seeding
• ✅ Seeding trackfinding | single muon | default seeding
• ✅ CKF | trackfinding | single muon | default seeding
• ✅ Track Summary CKF | trackfinding | single muon | default seeding
• ✅ Seeding trackfinding | single muon | orthogonal seeding
• ✅ CKF | trackfinding | single muon | orthogonal seeding
• ✅ Track Summary CKF | trackfinding | single muon | orthogonal seeding
• ✅ Seeding trackfinding | 4 muon x 50 vertices | default seeding
• ✅ CKF | trackfinding | 4 muon x 50 vertices | default seeding
• ✅ Track Summary CKF | trackfinding | 4 muon x 50 vertices | default seeding
• ✅ Ambisolver | trackfinding | 4 muon x 50 vertices | default seeding
• ✅ IVF notime | trackfinding | 4 muon x 50 vertices | default seeding
• ✅ AMVF gauss notime | trackfinding | 4 muon x 50 vertices | default seeding
• ✅ AMVF grid time | trackfinding | 4 muon x 50 vertices | default seeding
• ✅ Seeding trackfinding | ttbar with 200 pileup | default seeding
• ✅ CKF | trackfinding | ttbar with 200 pileup | default seeding
• ✅ Track Summary CKF | trackfinding | ttbar with 200 pileup | default seeding
• ✅ Ambisolver | trackfinding | ttbar with 200 pileup | default seeding
• ✅ AMVF gauss notime | trackfinding | ttbar with 200 pileup | default seeding
• ✅ AMVF grid time | trackfinding | ttbar with 200 pileup | default seeding

[sonarcloud]

Quality Gate passed

Issues
9 New issues
0 Accepted issues

Measures
0 Security Hotspots
61.8% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[paulgessinger]

Like @andiwand says it might be worth thinking about if we want to retire this typedef entirely at this point, since it doesn't really serve a purpose anymore.

[AJPfleger]

We will have a discussion during the workshop next week, how we should proceed on the topic ActsScalar. Currently it seems, that the cost of keeping it outweights the benefits.

[AJPfleger]

Let's remove it:

• refactor!: remove ActsScalar #3873