RE: too many errors

Hi Jing,

I have a couple of comments about your file.
1st) You use a material name of more than eight characters
("METHANE-1"). Bear in mind that FLUKA is probably only looking at the
eight first characters ("METHANE-"). In this case I don't think that
this is a major problem, but if you had two materials with different
endings (e.g. METHANE-1 and METHANE-2), then one of them would overwrite
the other or it may even trigger an error.

2nd) You make an abundant use of the 'BOX'. Note that this type of body
has been obsoleted and, although many of use like to use it from time to
time, we have to make sure that the vectors defining the three
dimensions are PERFECTLY perpendicular. I randomly checked two of your
BOX bodies and in both cases I found that the scalar product of the
vectors in the {Y,Z} plane was NOT zero. This is certainly going to
entail some geometry errors, as it indeed happens. Of course, for short
enough simulations, particles may not reach the conflictual areas (or
may reach them from a 'good' side or angle), but occasionally you will
have showers in that area and particles that FLUKA cannot put back on
track. I visualized your geometry and couldn't see any visible error, so
I am almost sure that all your problems come from the inaccurate BOX.
You have several solutions
a) don't use BOX, use RPP and planes
b) make sure your BOX axis are perfectly perpendicular
c) relax the precision of your tracking
d) combine solutions b) and c)

Mario

-----Original Message-----
From: owner-fluka-discuss_at_mi.infn.it on behalf of Hantao Jing
Sent: Wed 3/3/2010 3:34 PM
To: fluka-discuss_at_fluka.org
Subject: too many errors
 
Dear fluka experts,
      When I run my job with different-random input files on farm. All
of other input files can be run correctly. But only one job appear the
following errors repeatedly. The errors are so many that the file of
'CSNSBN25005.err' is almost 77MB. These errors appear from the cycle 004
to 010. I guess, the reason is that produced random seeds may be wrong
or bad. The random seed in this input file is 17402936.. Why dose the
error appear?
     Thank you in advance.

      Try again to establish the current region moving the particle of
a 1.000000000E-08 long step
  We succeeded in saving the particle: current region is n. 21 (cell
# 0)
  Geofar: Particle in region 21 (cell # 0) in position
-2.761064634E+00 2.386453261E-01 -1.994145119E-01
   is now causing trouble, requesting a step of 2.083500048E+00 cm
   to direction -7.672281274E-01 3.666300396E-02 6.403255615E-01,
error count: **
   R2: 2.771358783E+00 R3: 2.778524006E+00 cm
   X*U (2D): 2.127115903E+00 X*U (3D): 1.999425694E+00 cm
   X*UOLD(2D): 2.127115903E+00 X*UOLD(3D): 1.999425694E+00 cm
   Kloop: 9143777, Irsave: 21, Irsav2: 21, error code: -33
Nfrom: 1001
   old direction -7.672281274E-01 3.666300396E-02 6.403255615E-01,
lagain, lstnew, lsense, lsnsct F F F F
   Particle index 8 total energy 9.395656722E-01 GeV Nsurf 0
  Try again to establish the current region moving the particle of a
1.000000000E-08 long step
  We succeeded in saving the particle: current region is n. 21 (cell
# 0)
  Abort called from FLKAG1 reason TOO MANY ERRORS IN GEOMETRY Run stopped!
  STOP TOO MANY ERRORS IN GEOMETRY
Received on Thu Mar 04 2010 - 11:19:42 CET