PixelPairStep_cff.py

Go to the documentation of this file.

import FWCore.ParameterSet.Config as cms
from Configuration.Eras.Modifier_tracker_apv_vfp30_2016_cff import tracker_apv_vfp30_2016 as _tracker_apv_vfp30_2016
import RecoTracker.IterativeTracking.iterativeTkConfig as _cfg
from Configuration.Eras.Modifier_fastSim_cff import fastSim

# NEW CLUSTERS (remove previously used clusters)
pixelPairStepClusters = _cfg.clusterRemoverForIter("PixelPairStep")
for _eraName, _postfix, _era in _cfg.nonDefaultEras():
    _era.toReplaceWith(pixelPairStepClusters, _cfg.clusterRemoverForIter("PixelPairStep", _eraName, _postfix))


# SEEDING LAYERS
pixelPairStepSeedLayers = cms.EDProducer("SeedingLayersEDProducer",
    layerList = cms.vstring('BPix1+BPix2', 'BPix1+BPix3', 'BPix2+BPix3', 
        'BPix1+FPix1_pos', 'BPix1+FPix1_neg', 
        'BPix2+FPix1_pos', 'BPix2+FPix1_neg', 
        'FPix1_pos+FPix2_pos', 'FPix1_neg+FPix2_neg'),
    BPix = cms.PSet(
        TTRHBuilder = cms.string('WithTrackAngle'),
        HitProducer = cms.string('siPixelRecHits'),
        skipClusters = cms.InputTag('pixelPairStepClusters')
    ),
    FPix = cms.PSet(
        TTRHBuilder = cms.string('WithTrackAngle'),
        HitProducer = cms.string('siPixelRecHits'),
        skipClusters = cms.InputTag('pixelPairStepClusters')
    )
)
# layers covering the region not covered by quadruplets (so it is
# just acting as backup of triplets)
_layerListForPhase1 = [
    'BPix1+BPix2', 'BPix1+BPix3', 'BPix2+BPix3',
    'BPix1+FPix1_pos', 'BPix1+FPix1_neg',
    'BPix2+FPix1_pos', 'BPix2+FPix1_neg',
]
from Configuration.Eras.Modifier_trackingPhase1_cff import trackingPhase1
trackingPhase1.toModify(pixelPairStepSeedLayers, layerList = _layerListForPhase1)

# only layers covering the region not covered by quadruplets
# (so it is just acting as backup of triplets)
_layerListForPhase2 = [
        'BPix1+BPix2', 'BPix1+BPix3', 'BPix2+BPix3',
        'BPix1+FPix1_pos', 'BPix1+FPix1_neg',
        'BPix2+FPix1_pos', 'BPix2+FPix1_neg'
]
# modifing these errors seems to make no difference
from Configuration.Eras.Modifier_trackingPhase2PU140_cff import trackingPhase2PU140
trackingPhase2PU140.toModify(pixelPairStepSeedLayers, 
    layerList = _layerListForPhase2,
    BPix = dict(
        useErrorsFromParam = cms.bool(True),
        hitErrorRPhi = cms.double(0.0016),
        hitErrorRZ = cms.double(0.0035),
        TTRHBuilder = cms.string('TTRHBuilderWithoutAngle4PixelPairs'),
    ),
    FPix = dict(
        useErrorsFromParam = cms.bool(True),
        hitErrorRPhi = cms.double(0.0030),
        hitErrorRZ = cms.double(0.0020),
        TTRHBuilder = cms.string('TTRHBuilderWithoutAngle4PixelPairs'),
    )
)

# TrackingRegion
from RecoTracker.TkTrackingRegions.globalTrackingRegionWithVertices_cff import globalTrackingRegionWithVertices as _globalTrackingRegionWithVertices
pixelPairStepTrackingRegions = _globalTrackingRegionWithVertices.clone(RegionPSet = dict(
    ptMin = 0.6,
    originRadius = 0.015,
    fixedError = 0.03,
    useMultipleScattering = True,
))
from Configuration.Eras.Modifier_trackingLowPU_cff import trackingLowPU
trackingLowPU.toModify(pixelPairStepTrackingRegions, RegionPSet=dict(useMultipleScattering=False))
_region_Phase1 = dict(
    useMultipleScattering = False,
    maxNVertices = 5,
)
trackingPhase1.toModify(pixelPairStepTrackingRegions, RegionPSet=_region_Phase1)
trackingPhase2PU140.toModify(pixelPairStepTrackingRegions, RegionPSet=_region_Phase1)
from Configuration.Eras.Modifier_highBetaStar_2018_cff import highBetaStar_2018
highBetaStar_2018.toModify(pixelPairStepTrackingRegions,RegionPSet = dict(
     ptMin = 0.05,
     originRadius = 0.2,
     fixedError = 4.
))
fastSim.toModify(pixelPairStepTrackingRegions, RegionPSet=dict(VertexCollection = "firstStepPrimaryVerticesBeforeMixing"))

# SEEDS
from RecoTracker.TkHitPairs.hitPairEDProducer_cfi import hitPairEDProducer as _hitPairEDProducer
pixelPairStepHitDoublets = _hitPairEDProducer.clone(
    seedingLayers = "pixelPairStepSeedLayers",
    trackingRegions = "pixelPairStepTrackingRegions",
    produceSeedingHitSets = True,
    maxElementTotal = 12000000,
)
from RecoTracker.TkSeedGenerator.seedCreatorFromRegionConsecutiveHitsEDProducer_cff import seedCreatorFromRegionConsecutiveHitsEDProducer as _seedCreatorFromRegionConsecutiveHitsEDProducer
pixelPairStepSeeds = _seedCreatorFromRegionConsecutiveHitsEDProducer.clone(
    seedingHitSets = "pixelPairStepHitDoublets",
    SeedComparitorPSet = dict(# FIXME: is this defined in any cfi that could be imported instead of copy-paste?
        ComponentName = 'PixelClusterShapeSeedComparitor',
        FilterAtHelixStage = cms.bool(True),
        FilterPixelHits = cms.bool(True),
        FilterStripHits = cms.bool(False),
        ClusterShapeHitFilterName = cms.string('ClusterShapeHitFilter'),
        ClusterShapeCacheSrc = cms.InputTag('siPixelClusterShapeCache'),
    )
)

# Clone for the phase1 recovery mode
pixelPairStepSeedsA = pixelPairStepSeeds.clone()

#have to do it after making pixelPairStepSeedsA since pixelPairStepSeedsB clones A
# and then modifies it
import FastSimulation.Tracking.TrajectorySeedProducer_cfi
fastSim.toReplaceWith(pixelPairStepSeeds,
                      FastSimulation.Tracking.TrajectorySeedProducer_cfi.trajectorySeedProducer.clone(
        trackingRegions = "pixelPairStepTrackingRegions",
        hitMasks = cms.InputTag("pixelPairStepMasks"),
        seedFinderSelector = dict(layerList = pixelPairStepSeedLayers.layerList.value())
        )
)

# Recovery for regions with 2 inactive layers
from RecoTracker.TkTrackingRegions.pixelInactiveAreaTrackingRegionsAndSeedingLayers_cfi import pixelInactiveAreaTrackingRegionsAndSeedingLayers as _pixelInactiveAreaTrackingRegionsAndSeedingLayers
pixelPairStepTrackingRegionsSeedLayersB = _pixelInactiveAreaTrackingRegionsAndSeedingLayers.clone(
    layerList = [
# Commented ones are already included in the global seeds (A), but are
# included below for completenees
#
#        "BPix1+BPix2",
#        "BPix1+BPix3",
        "BPix1+BPix4",
#        "BPix2+BPix3",
        "BPix2+BPix4",
        "BPix3+BPix4",
#        "BPix1+FPix1_pos"    , "BPix1+FPix1_neg",
        "BPix1+FPix2_pos"    , "BPix1+FPix2_neg",
        "BPix1+FPix3_pos"    , "BPix1+FPix3_neg",
#        "BPix2+FPix1_pos"    , "BPix2+FPix1_neg",
        "BPix2+FPix2_pos"    , "BPix2+FPix2_neg",
        "BPix3+FPix1_pos"    , "BPix3+FPix1_neg",
        "FPix1_pos+FPix2_pos", "FPix1_neg+FPix2_neg",
        "FPix1_pos+FPix3_pos", "FPix1_neg+FPix3_neg",
        "FPix2_pos+FPix3_pos", "FPix2_neg+FPix3_neg",
    ],
    BPix = dict(
        TTRHBuilder = cms.string('WithTrackAngle'),
        HitProducer = cms.string('siPixelRecHits'),
        skipClusters = cms.InputTag('pixelPairStepClusters')
    ),
    FPix = dict(
        TTRHBuilder = cms.string('WithTrackAngle'),
        HitProducer = cms.string('siPixelRecHits'),
        skipClusters = cms.InputTag('pixelPairStepClusters')
    ),
    RegionPSet = dict(
        ptMin = 0.6,
        originRadius = 0.015,
        operationMode = "VerticesFixed",
        zErrorVertex = 0.03,
        maxNVertices = 5,
    ),
    ignoreSingleFPixPanelModules = True,
)
highBetaStar_2018.toModify(pixelPairStepTrackingRegionsSeedLayersB,RegionPSet = dict(
     ptMin = 0.05,
     originRadius = 0.2,
))
#include commented lines from above in pp_on_XY eras; global seeds (A) are not used in this era b/c timing
from Configuration.Eras.Modifier_pp_on_XeXe_2017_cff import pp_on_XeXe_2017
from Configuration.Eras.Modifier_pp_on_AA_2018_cff import pp_on_AA_2018
(pp_on_XeXe_2017 | pp_on_AA_2018).toModify(pixelPairStepTrackingRegionsSeedLayersB, layerList = [
      "BPix1+BPix2", "BPix1+BPix3", "BPix1+BPix4", "BPix2+BPix3", "BPix2+BPix4","BPix3+BPix4",
      "BPix1+FPix1_pos"    , "BPix1+FPix1_neg",
      "BPix1+FPix2_pos"    , "BPix1+FPix2_neg",
      "BPix1+FPix3_pos"    , "BPix1+FPix3_neg",
      "BPix2+FPix1_pos"    , "BPix2+FPix1_neg",
      "BPix2+FPix2_pos"    , "BPix2+FPix2_neg",
      "BPix3+FPix1_pos"    , "BPix3+FPix1_neg",
      "FPix1_pos+FPix2_pos", "FPix1_neg+FPix2_neg",
      "FPix1_pos+FPix3_pos", "FPix1_neg+FPix3_neg",
      "FPix2_pos+FPix3_pos", "FPix2_neg+FPix3_neg" 
   ])

pixelPairStepHitDoubletsB = pixelPairStepHitDoublets.clone(
    seedingLayers = "",
    trackingRegions = "",
    trackingRegionsSeedingLayers = "pixelPairStepTrackingRegionsSeedLayersB",
)
pixelPairStepSeedsB = pixelPairStepSeedsA.clone(seedingHitSets = "pixelPairStepHitDoubletsB")


# Merge
from RecoTracker.TkSeedGenerator.GlobalCombinedSeeds_cfi import globalCombinedSeeds as _globalCombinedSeeds
_pixelPairStepSeedsMerged = _globalCombinedSeeds.clone(
    seedCollections = ["pixelPairStepSeedsA", "pixelPairStepSeedsB"],
)
(trackingPhase1 & ~fastSim).toReplaceWith(pixelPairStepSeeds, _pixelPairStepSeedsMerged)

#only use region B for pp_on_XY era for timing reasons
(pp_on_XeXe_2017 | pp_on_AA_2018).toReplaceWith(pixelPairStepSeeds, pixelPairStepSeedsB)

# QUALITY CUTS DURING TRACK BUILDING
import TrackingTools.TrajectoryFiltering.TrajectoryFilter_cff
_pixelPairStepTrajectoryFilterBase = TrackingTools.TrajectoryFiltering.TrajectoryFilter_cff.CkfBaseTrajectoryFilter_block.clone(
    minimumNumberOfHits = 3,
    minPt = 0.1,
)
pixelPairStepTrajectoryFilterBase = _pixelPairStepTrajectoryFilterBase.clone(
    seedPairPenalty =0,
    maxCCCLostHits = 0,
    minGoodStripCharge = cms.PSet(refToPSet_ = cms.string('SiStripClusterChargeCutLoose'))
)
from Configuration.Eras.Modifier_tracker_apv_vfp30_2016_cff import tracker_apv_vfp30_2016
_tracker_apv_vfp30_2016.toModify(pixelPairStepTrajectoryFilterBase, maxCCCLostHits = 2)
trackingLowPU.toReplaceWith(pixelPairStepTrajectoryFilterBase, _pixelPairStepTrajectoryFilterBase)
trackingPhase1.toModify(pixelPairStepTrajectoryFilterBase, minimumNumberOfHits = 4)
trackingPhase2PU140.toReplaceWith(pixelPairStepTrajectoryFilterBase, _pixelPairStepTrajectoryFilterBase.clone(
    minimumNumberOfHits = 4,
    maxLostHitsFraction = 1./10.,
    constantValueForLostHitsFractionFilter = 0.701,
))
highBetaStar_2018.toModify(pixelPairStepTrajectoryFilterBase, minPt = 0.05)

import RecoPixelVertexing.PixelLowPtUtilities.StripSubClusterShapeTrajectoryFilter_cfi
pixelPairStepTrajectoryFilterShape = RecoPixelVertexing.PixelLowPtUtilities.StripSubClusterShapeTrajectoryFilter_cfi.StripSubClusterShapeTrajectoryFilterTIX12.clone()
pixelPairStepTrajectoryFilter = cms.PSet(
    ComponentType = cms.string('CompositeTrajectoryFilter'),
    filters = cms.VPSet(
        cms.PSet( refToPSet_ = cms.string('pixelPairStepTrajectoryFilterBase')),
    #    cms.PSet( refToPSet_ = cms.string('pixelPairStepTrajectoryFilterShape'))
    ),
)
from RecoPixelVertexing.PixelLowPtUtilities.ClusterShapeTrajectoryFilter_cfi import *
trackingPhase2PU140.toModify(pixelPairStepTrajectoryFilter,
    filters = pixelPairStepTrajectoryFilter.filters + [cms.PSet(refToPSet_ = cms.string('ClusterShapeTrajectoryFilter'))]
)



pixelPairStepTrajectoryFilterInOut = pixelPairStepTrajectoryFilterBase.clone(
    minimumNumberOfHits = 4,
    seedExtension = 1,
    strictSeedExtension = False, # allow inactive
    pixelSeedExtension = False,
)



import RecoTracker.MeasurementDet.Chi2ChargeMeasurementEstimator_cfi
pixelPairStepChi2Est = RecoTracker.MeasurementDet.Chi2ChargeMeasurementEstimator_cfi.Chi2ChargeMeasurementEstimator.clone(
    ComponentName = cms.string('pixelPairStepChi2Est'),
    nSigma = cms.double(3.0),
    MaxChi2 = cms.double(9.0),
    clusterChargeCut = cms.PSet(refToPSet_ = cms.string('SiStripClusterChargeCutLoose')),
    pTChargeCutThreshold = cms.double(15.)
)
_tracker_apv_vfp30_2016.toModify(pixelPairStepChi2Est,
    clusterChargeCut = dict(refToPSet_ = "SiStripClusterChargeCutTiny")
)
trackingLowPU.toModify(pixelPairStepChi2Est,
    clusterChargeCut = dict(refToPSet_ = 'SiStripClusterChargeCutTiny'),
)
highBetaStar_2018.toModify(pixelPairStepChi2Est,MaxChi2 = cms.double(30))

# TRACK BUILDING
import RecoTracker.CkfPattern.GroupedCkfTrajectoryBuilder_cfi
pixelPairStepTrajectoryBuilder = RecoTracker.CkfPattern.GroupedCkfTrajectoryBuilder_cfi.GroupedCkfTrajectoryBuilder.clone(
    MeasurementTrackerName = '',
    trajectoryFilter = cms.PSet(refToPSet_ = cms.string('pixelPairStepTrajectoryFilter')),
    maxCand = 3,
    estimator = cms.string('pixelPairStepChi2Est'),
    maxDPhiForLooperReconstruction = cms.double(2.0),
    maxPtForLooperReconstruction = cms.double(0.7) 
    )
trackingLowPU.toModify(pixelPairStepTrajectoryBuilder, maxCand = 2)
_seedExtension = dict(
    inOutTrajectoryFilter = dict(refToPSet_ = "pixelPairStepTrajectoryFilterInOut"),
    useSameTrajFilter = False,
)
trackingPhase1.toModify(pixelPairStepTrajectoryBuilder, **_seedExtension)
trackingPhase2PU140.toModify(pixelPairStepTrajectoryBuilder, **_seedExtension)




# MAKING OF TRACK CANDIDATES
import RecoTracker.CkfPattern.CkfTrackCandidates_cfi
pixelPairStepTrackCandidates = RecoTracker.CkfPattern.CkfTrackCandidates_cfi.ckfTrackCandidates.clone(
    src = cms.InputTag('pixelPairStepSeeds'),
    clustersToSkip = cms.InputTag('pixelPairStepClusters'),
    TrajectoryBuilderPSet = cms.PSet(refToPSet_ = cms.string('pixelPairStepTrajectoryBuilder')),
    ### these two parameters are relevant only for the CachingSeedCleanerBySharedInput
    numHitsForSeedCleaner = cms.int32(50),
    onlyPixelHitsForSeedCleaner = cms.bool(True),

)
trackingPhase2PU140.toModify(pixelPairStepTrackCandidates,
    clustersToSkip = None,
    phase2clustersToSkip = cms.InputTag("pixelPairStepClusters"),
    TrajectoryCleaner = "pixelPairStepTrajectoryCleanerBySharedHits"
)
import FastSimulation.Tracking.TrackCandidateProducer_cfi
fastSim.toReplaceWith(pixelPairStepTrackCandidates,
                      FastSimulation.Tracking.TrackCandidateProducer_cfi.trackCandidateProducer.clone(
        src = cms.InputTag("pixelPairStepSeeds"),
        MinNumberOfCrossedLayers = 2, # ?
        hitMasks = cms.InputTag("pixelPairStepMasks")
        )
)

from TrackingTools.TrajectoryCleaning.TrajectoryCleanerBySharedHits_cfi import trajectoryCleanerBySharedHits as _trajectoryCleanerBySharedHits
pixelPairStepTrajectoryCleanerBySharedHits = _trajectoryCleanerBySharedHits.clone(
    ComponentName = 'pixelPairStepTrajectoryCleanerBySharedHits',
    fractionShared = 0.095,
    allowSharedFirstHit = True
)
trackingPhase2PU140.toModify(pixelPairStepTrajectoryCleanerBySharedHits, fractionShared = 0.09)

# TRACK FITTING
import RecoTracker.TrackProducer.TrackProducer_cfi
pixelPairStepTracks = RecoTracker.TrackProducer.TrackProducer_cfi.TrackProducer.clone(
    AlgorithmName = cms.string('pixelPairStep'),
    src = 'pixelPairStepTrackCandidates',
    Fitter = cms.string('FlexibleKFFittingSmoother')
    )
fastSim.toModify(pixelPairStepTracks, TTRHBuilder = 'WithoutRefit')

# Final selection
from RecoTracker.FinalTrackSelectors.TrackMVAClassifierPrompt_cfi import *
pixelPairStep =  TrackMVAClassifierPrompt.clone()
pixelPairStep.src = 'pixelPairStepTracks'
pixelPairStep.mva.GBRForestLabel = 'MVASelectorIter2_13TeV'
pixelPairStep.qualityCuts = [-0.2,0.0,0.3]
highBetaStar_2018.toModify(pixelPairStep,qualityCuts = [-0.95,0.0,0.3])

trackingPhase1.toModify(pixelPairStep, mva=dict(GBRForestLabel = 'MVASelectorPixelPairStep_Phase1'))
fastSim.toModify(pixelPairStep, vertices = "firstStepPrimaryVerticesBeforeMixing")
pp_on_AA_2018.toModify(pixelPairStep, qualityCuts = [-0.2, 0.0, 0.9])

# For LowPU and Phase2PU140
import RecoTracker.IterativeTracking.LowPtTripletStep_cff
import RecoTracker.FinalTrackSelectors.multiTrackSelector_cfi
pixelPairStepSelector = RecoTracker.FinalTrackSelectors.multiTrackSelector_cfi.multiTrackSelector.clone(
    src='pixelPairStepTracks',
    useAnyMVA = cms.bool(True),
    GBRForestLabel = cms.string('MVASelectorIter2'),
    trackSelectors= cms.VPSet(
        RecoTracker.FinalTrackSelectors.multiTrackSelector_cfi.looseMTS.clone(
            name = 'pixelPairStepLoose',
        ), #end of pset
        RecoTracker.FinalTrackSelectors.multiTrackSelector_cfi.tightMTS.clone(
            name = 'pixelPairStepTight',
            preFilterName = 'pixelPairStepLoose',
        ),
        RecoTracker.FinalTrackSelectors.multiTrackSelector_cfi.highpurityMTS.clone(
            name = 'QualityMasks',
            preFilterName = 'pixelPairStepTight',
        ),
    ),
    vertices = cms.InputTag("pixelVertices")#end of vpset
) #end of clone
trackingPhase2PU140.toModify(pixelPairStepSelector,
    useAnyMVA = None,
    GBRForestLabel = None,
    trackSelectors= cms.VPSet(
        RecoTracker.FinalTrackSelectors.multiTrackSelector_cfi.looseMTS.clone(
            name = 'pixelPairStepLoose',
            chi2n_par = 0.7,
            res_par = ( 0.003, 0.002 ),
            minNumberLayers = 3,
            maxNumberLostLayers = 2,
            minNumber3DLayers = 3,
            d0_par1 = ( 0.4, 4.0 ),
            dz_par1 = ( 0.4, 4.0 ),
            d0_par2 = ( 0.6, 4.0 ),
            dz_par2 = ( 0.45, 4.0 )
            ), #end of pset
        RecoTracker.FinalTrackSelectors.multiTrackSelector_cfi.tightMTS.clone(
            name = 'pixelPairStepTight',
            preFilterName = 'pixelPairStepLoose',
            chi2n_par = 0.6,
            res_par = ( 0.003, 0.002 ),
            minNumberLayers = 4,
            maxNumberLostLayers = 2,
            minNumber3DLayers = 3,
            d0_par1 = ( 0.35, 4.0 ),
            dz_par1 = ( 0.35, 4.0 ),
            d0_par2 = ( 0.5, 4.0 ),
            dz_par2 = ( 0.4, 4.0 )
            ),
        RecoTracker.FinalTrackSelectors.multiTrackSelector_cfi.highpurityMTS.clone(
            name = 'pixelPairStep',
            preFilterName = 'pixelPairStepTight',
            chi2n_par = 0.5,
            res_par = ( 0.003, 0.001 ),
            minNumberLayers = 5,
            maxNumberLostLayers = 2,
            minNumber3DLayers = 4,
            d0_par1 = ( 0.3, 4.0 ),
            dz_par1 = ( 0.3, 4.0 ),
            d0_par2 = ( 0.45, 4.0 ),
            dz_par2 = ( 0.35, 4.0 )
            ),
        ), #end of vpset
    vertices = "firstStepPrimaryVertices"
) #end of clone


# Final sequence
PixelPairStepTask = cms.Task(pixelPairStepClusters,
                         pixelPairStepSeedLayers,
                         pixelPairStepTrackingRegions,
                         pixelPairStepHitDoublets,
                         pixelPairStepSeeds,
                         pixelPairStepTrackCandidates,
                         pixelPairStepTracks,
                         pixelPairStep)
PixelPairStep = cms.Sequence(PixelPairStepTask)

_PixelPairStepTask_LowPU_Phase2PU140 = PixelPairStepTask.copy()
_PixelPairStepTask_LowPU_Phase2PU140.replace(pixelPairStep, pixelPairStepSelector)
trackingLowPU.toReplaceWith(PixelPairStepTask, _PixelPairStepTask_LowPU_Phase2PU140)
trackingPhase2PU140.toReplaceWith(PixelPairStepTask, _PixelPairStepTask_LowPU_Phase2PU140)

_PixelPairStepTask_Phase1 = PixelPairStepTask.copy()
_PixelPairStepTask_pp_on_AA = PixelPairStepTask.copy()
_PixelPairStepTask_Phase1.replace(pixelPairStepSeeds,cms.Task(
                              pixelPairStepSeedsA ,
                              pixelPairStepTrackingRegionsSeedLayersB,pixelPairStepHitDoubletsB,pixelPairStepSeedsB,
                              pixelPairStepSeeds))
trackingPhase1.toReplaceWith(PixelPairStepTask, _PixelPairStepTask_Phase1)

_PixelPairStepTask_pp_on_AA.replace(pixelPairStepHitDoublets, cms.Task(pixelPairStepTrackingRegionsSeedLayersB,pixelPairStepHitDoubletsB))
(pp_on_XeXe_2017 | pp_on_AA_2018).toReplaceWith(PixelPairStepTask, _PixelPairStepTask_pp_on_AA)

#fastSim
import FastSimulation.Tracking.FastTrackerRecHitMaskProducer_cfi
pixelPairStepMasks = FastSimulation.Tracking.FastTrackerRecHitMaskProducer_cfi.maskProducerFromClusterRemover(pixelPairStepClusters)
fastSim.toReplaceWith(PixelPairStepTask,
                      cms.Task(pixelPairStepMasks
                                   ,pixelPairStepTrackingRegions
                                   ,pixelPairStepSeeds
                                   ,pixelPairStepTrackCandidates
                                   ,pixelPairStepTracks
                                   ,pixelPairStep 
                                   )
)