fastjet.ClusterSequence

class fastjet.ClusterSequence(data, jetdef)

The base class for all clustering.

Parameters
  • data (awkward.highlevel.Array) – The data for clustering.

  • jetdef (fastjet._swig.JetDefinition) – The JetDefinition for clustering specification.

Q()

Returns the sum of all energies in the event (relevant mainly for e+e-)

Parameters

None

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

Q2()

Return Q()^2

Parameters

None

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

childless_pseudojets()

Return the list of pseudojets in the ClusterSequence that do not have children (and are not among the inclusive jets).

Parameters

None

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

constituent_index(min_pt=0)

Returns the index of the constituent of each Jet.

Parameters

min_pt (float) – The minimum value of the pt for the inclusive jets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

constituents(min_pt=0)

Returns the particles that make up each Jet.

Parameters

min_pt (float) – The minimum value of the pt for the inclusive jets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_dmerge(njets=10)

Returns the dmin corresponding to the recombination that went from n+1 to n jets.

Parameters

n_jets (int) – The number of jets it was clustered to.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_dmerge_max(njets=10)

Returns the maximum of the dmin encountered during all recombinations up to the one that led to an n-jet final state.

Parameters

n_jets (int) – The number of jets it was clustered to.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_jets(n_jets=- 1, dcut=- 1)

Returns the exclusive jets after clustering in the same format as the input awkward array. Either takes njets or dcut as argument.

Parameters
  • n_jets (int) – The number of jets it was clustered to.

  • dcut (float) – The dcut for the result.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_jets_ycut(ycut=- 1)

Returns the exclusive jets after clustering in the same format as the input awkward array.

Parameters

ycut (float) – The dcut for the result.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_subdmerge(data, nsub=0)

Returns the dij that was present in the merging nsub+1 -> nsub subjets inside this jet.

Parameters
  • data (awkward.highlevel.Array) – An Awkward Array containing the Jets.

  • n_sub (int) – The number of subjets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_subdmerge_max(data, nsub=0)

Returns the maximum dij that occurred in the whole event at the stage that the nsub+1 -> nsub merge of subjets occurred inside this jet.

Parameters
  • data (awkward.highlevel.Array) – An Awkward Array containing the Jets.

  • n_sub (int) – The number of subjets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_subjets(data, dcut=- 1, nsub=- 1)

Returns an Awkward Array of all subjets of the current jet (in the sense of the exclusive algorithm) that would be obtained when running the algorithm with the given dcut.

Parameters
  • data (awkward.highlevel.Array) – An Array containing the Jets.

  • dcut (float) – The dcut for the result.

  • n_sub (int) – The number of subjets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_subjets_up_to(data, nsub=0)

Returns the list of subjets obtained by unclustering the supplied jet down to nsub subjets (or all constituents if there are fewer than nsub).

Parameters
  • data (awkward.highlevel.Array) – An Awkward Array containing the Jets.

  • n_sub (int) – The number of subjets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_ymerge(njets=10)

Returns the ymin corresponding to the recombination that went from n+1 to n jets.

Parameters

n_jets (int) – The number of jets it was clustered to.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

exclusive_ymerge_max(njets=10)

Same as exclusive_dmerge_max, but normalised to squared total energy.

Parameters

n_jets (int) – The number of jets it was clustered to.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

get_child(data)

If the jet has parents in the clustering, it returns them.

Parameters

data (awkward.highlevel.Array) – An Array containing the Jets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

get_parents(data)

If the jet has parents in the clustering, it returns them.

Parameters

data (awkward.highlevel.Array) – An Array containing the Jets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

has_child(data)

If the jet has children in the clustering, it returns true.

Parameters

data (awkward.highlevel.Array) – An Array containing the Jets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

has_parents(data)

if the jet has parents in the clustering, it returns true.

Parameters

data (awkward.highlevel.Array) – An Array containing the Jets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

inclusive_jets(min_pt=0)

Returns the inclusive jets after clustering in the same format as the input awkward array

Parameters

min_pt (float) – The minimum value of the pt for the inclusive jets.

Returns

Returns an Awkward Array of the same type as the input containting inclusive jets.

Return type

awkward.highlevel.Array

jet_def()

Returns the Jet Definition Object associated with the instance

Parameters

None

Returns

Returns the jetdefinition stored as an attribute.

Return type

JetDefinition

jet_scale_for_algorithm(data)

Returns the scale associated with a jet as required for this clustering algorithm (kt^2 for the kt-algorithm, 1 for the Cambridge algorithm).

Parameters

data (awkward.highlevel.Array) – An Array containing the Jets.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

jets()

Allows the user to access the internally stored _jets() array, which contains both the initial particles and the various intermediate and final stages of recombination.

Parameters

none

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

n_exclusive_jets(dcut=0)

Returns the number of jets (in the sense of the exclusive algorithm) that would be obtained when running the algorithm with the given dcut.

Parameters

dcut (float) – The dcut for the result.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

n_exclusive_subjets(data, dcut=0)

Returns the size of exclusive_subjets(…); still n ln n with same coefficient, but marginally more efficient than manually taking len(exclusive_subjets)

Parameters
  • data (awkward.highlevel.Array) – An Array containing the Jets.

  • dcut (float) – The dcut for the result.

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

n_particles()

Returns the number of particles that were provided to the clustering algorithm.

Parameters

None

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array

unclustered_particles()

Returns the unclustered particles after clustering in the same format as the input awkward array

Parameters

None

Returns

Returns an Awkward Array of the same type as the input contating the unclustered particles.

Return type

awkward.highlevel.Array

unique_history_order()

Routine that returns an order in which to read the history such that clusterings that lead to identical jet compositions but different histories (because of degeneracies in the clustering order) will have matching constituents for each matching entry in the unique_history_order.

Parameters

None

Returns

Returns an Awkward Array of the same type as the input.

Return type

awkward.highlevel.Array