Problem 1872

Summary: GeomNav0003, Current Point appears to be Outside mother volume !!
Product: Geant4 Reporter: lebrun
Component: trackingAssignee: Takashi.Sasaki
Status: RESOLVED INVALID    
Severity: major    
Priority: P5    
Version: 10.2   
Hardware: All   
OS: Linux   
Attachments: tar file of the stand alone example where G4 tracking produce warnings.

Description lebrun 2016-06-16 21:47:47 CEST
Created attachment 406 [details]
tar file of the stand alone example where G4 tracking produce warnings.

This could be indeed an other aspect of bug 1709. Not sure. 

The complete output is:

*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------


-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : GeomNav0003
      issued by : G4NormalNavigation::ComputeStep()
============================================================
 WARNING>  Current Point appears to be Outside mother volume !! 
   Response of DistanceToOut was negative or kInfinity when called in G4NormalNavigation::ComputeStep()
   Current physical volume = Horn1_P
   Position (loc)  = (-128.6019051,310.2952873,906.3475708)
   Direction (dir) = (0.3235313105,-0.1622727368,0.9321990399)
 For confirmation:
   Response of DistanceToOut (loc, +dir)= 9e+99
   Response of DistanceToOut (loc, -dir)= 474.1826778
   Inside responds = 2 , ie:  Inside  -- unexpected / inconsistent response ! 
   Obtain safety(ToIn) = 415.2837442
   Obtain safety(ToOut) = 143.1607097
 Response of DistanceToIn (loc, +dir)= 9e+99
 Response of DistanceToIn (loc, -dir)= 9e+99
 Exit Normal at loc = (-0.3828699182,0.9238022655,-0)
     Dir . Normal   = -0.2737783283
 Checking points moved from position by distance/dir.  Solid responses: 
  +eps in direction :    kInside  +eps in Normal  :    kInside
  -eps in direction :    kInside  -eps in Normal  :    kInside
 Parameters of solid:     
-----------------------------------------------------------
    *** Dump for solid - Horn1 ***
    ===================================================
 Solid type: G4GenericPolycone
 Parameters: 
    starting phi angle : 0 degrees 
    ending phi angle   : 360 degrees 
    number of RZ points: 9
              RZ values (corners): 
                         479.05, 1374.0745
                         337.95, 1374.0245
                         337.95, 1464.0255
                         135.45, 1464.0245
                         134.45, 1369.0245
                         33.95, 481.6494999999998
                         33.95, -1462.9755
                         449.95, -1463.9755
                         479.05, -1464.0255
-----------------------------------------------------------
============================================================
*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------

Notes: 

  It does not happen for every track. You'll need to run many tracks. 

  A magnetic field (horn-like, 1/r) is attached to this Horn1 volume.  The shape of it is a bit tricky, it has a bulge on the downstream end. I have not 
studied this in detail, i.e, dependence on momentum, magnetic field in the bulge, etc... 

  Meanwhile, I'll attach the example. This is not what LBNF is running for the simulation of the neutrino beam line, obviously, but it demonstrates. the problem.  

  Questions:  Is this problem serious? What is the loss of accuracy ? If not, how can I suppress these warnings?
Comment 1 Takashi.Sasaki 2016-06-17 00:26:27 CEST
please report only bugs here. Other things should be posted in HyperNews instead.