Building radiusOfInnermostHit from tracks

[farakiko]

• EDM4hep version: unfortunately unsure because it was a nightly build from about 5 months ago
• Reproduced by: running the piece of code below
• Input: rootfile can be found here

Hi, I was looking into computing the radiusOfInnerMostHit because I need to use this variable for particle flow reconstruction. Since I have access to events generated with a previous software build that still has access to SiTracks_Refitted/SiTracks_Refitted.radiusOfInnermostHit, I was trying to confirm my piece of code below:

import math
import uproot

# load file
events = uproot.open("reco_p8_ee_tt_ecm365_100001.root")["events"]

# debug first event
iev = 0  
num_tracks = len(events["SiTracks_Refitted/SiTracks_Refitted.radiusOfInnermostHit"].array()[iev])

for itrack in range(num_tracks):
    
    val = events["SiTracks_Refitted/SiTracks_Refitted.radiusOfInnermostHit"].array()[iev][itrack]
    print(f"reading from branch; radiusOfInnermostHit of track {itrack} is: {val:.4f}")
    
    ############# now attempt to compute it using other branches
    # select the track states corresponding to itrack
    ibegin = events["SiTracks_Refitted/SiTracks_Refitted.trackStates_begin"].array()[iev][itrack]
    iend = events["SiTracks_Refitted/SiTracks_Refitted.trackStates_end"].array()[iev][itrack]

    num_track_states = iend - ibegin
    
    col = "_SiTracks_Refitted_trackStates"

    d0 = events[f"{col}/{col}.D0"].array()[iev][ibegin:iend]
    phi = events[f"{col}/{col}.phi"].array()[iev][ibegin:iend]
    refX = events[f"{col}/{col}.referencePoint.x"].array()[iev][ibegin:iend]
    refY = events[f"{col}/{col}.referencePoint.y"].array()[iev][ibegin:iend]    
    
    innermost_radius = float('inf')
    for ihit in range(num_track_states):
        x_closest = refX[ihit] + d0[ihit] * math.cos(phi[ihit])
        y_closest = refY[ihit] + d0[ihit] * math.sin(phi[ihit])
        
        radius = math.sqrt(x_closest**2 + y_closest**2)

        if radius < innermost_radius:
            innermost_radius = radius

    print(f"manually computed radiusOfInnermostHit of track {itrack} is: {innermost_radius:.4f}")
    break

which prints out:

reading from branch; radiusOfInnermostHit of track 0 is: 35.6223
manually computed radiusOfInnermostHit of track 0 is: 0.4091

Unfortunately, it seems that my piece of code is not correct because it does not match the value directly obtained from the branch SiTracks_Refitted/SiTracks_Refitted.radiusOfInnermostHit

Could you perhaps share how to build this variable from the other branches? Thanks!

[andresailer]

Thanks for providing the source code, but @tmadlener was faster in opening a separate issue, and started answering, so let's continue there: #383