Struct ActsFatras::FreeParametersSmearer

template<typename generator_t, size_t kSize>
struct FreeParametersSmearer

Uncorrelated smearing algorithm for fast digitisation of free parameters.

The smearer takes a single simulated Hit and generates a smeared parameter vector and associated covariance matrix.


Uncorrelated smearing of the direction using each components individually is not recommended

Template Parameters
  • generator_t – Random number generator type

  • kSize – Number of smeared parameters

Public Types

using CovarianceMatrix = Acts::ActsSymMatrix<kSize>
using ParametersVector = Acts::ActsVector<kSize>
using Result = Acts::Result<std::pair<ParametersVector, CovarianceMatrix>>
using Scalar = Acts::ActsScalar

Public Functions

inline Result operator()(generator_t &rng, const Hit &hit) const

Generate smeared measured for configured parameters.

  • rng – Random number generator

  • hit – Simulated hit

Return values
  • Smeared – parameters vector and associated covariance on success

  • Error – code for failure


Smeared free parameter set wrapped in a Result<…> object

Public Members

std::array<Acts::FreeIndices, kSize> indices = {}

Parameter indices that will be used to create the smeared measurements.

std::array<SingleParameterSmearFunction<generator_t>, kSize> smearFunctions

Public Static Functions

static inline constexpr size_t size()