[mcstas-users] Still problem running > 4e9 source neutrons...

Fri May 2 14:15:01 CEST 2025

Hi Peter,

I did  not get around to package the instrument and separate the stuff needed from what is just hanging around in the folder 😊
I will do that but I’d prefer to send the complete instrument to you personally and not prune the code because
of the uncertainty what is happening… and I’ll have to send a couple of comments with it!

As  I mentioned before the identical instrument ran just fine with 3.5.23 and Monitor_nD has not given me any problem one
I learned how to use it. I noticed that event files are – reliably – updated during a run when necessary and no more than 4e9 neutrons
are requested but not when I ask for 5e9 in version 3.5.24… I did not pickup on this hint 😊

I’ll try a bigger event buffer first though – may be it is as simple as that.

Thanks again,

Uli

From: Peter Kjær Willendrup <pkwi at dtu.dk>
Date: Thursday, May 1, 2025 at 12:01 PM
To: Wildgruber, Christoph U. <wildgrubercu at ornl.gov>
Cc: McStas <mcstas-users at mcstas.org>
Subject: [EXTERNAL] Re: [mcstas-users] Still problem running > 4e9 source neutrons...
Hi Uli, Hmm… Would be nice with access to instr code + all required nuts and bolts to reproduce? That said, I have on my list to dig deeper into a periodic issue with event lists in Monitor_nD, likely relating to dynamic reallocation of the

Hi Uli,

Hmm… Would be nice with access to instr code + all required nuts and bolts to reproduce?

That said, I have on my list to dig deeper into a periodic issue with event lists in Monitor_nD, likely relating to dynamic reallocation of the event list buffer.

With unmodified code you might be able to work around the problem by using a bigger event list buffer? Try adjusting the ‘bufsiz’ (is an option of the sim binaries as well as mcrun)

--bufsiz=BUFSIZ     Monitor_nD list/buffer-size (defaults to 10000000)
(from mcrun --help)

Best,
Peter

On 1 May 2025, at 17.30, Wildgruber, Christoph U. via mcstas-users <mcstas-users at mcstas.org> wrote:

Hi everybody,

I was (trying to) follow(ing) Peter’s suggestion and updated the ‘xcode command line tools’ (and reinstalled xcode too)
on my M2 MBP. The the same instrument runs fine with 5e8 source neutrons (I did not try yet 4e9, but I will)
with 5e9 however I get the same error message(s) I got yesterday before the ‘xcode’ update (copy from mcgui-py)
I am running single threaded btw…:

Incoherent: incCube: Vc=13.827 [Angs] sigma_abs=0.001 [barn] sigma_inc=5 [barn]
Monitor_nD: Crystal_15_out is a Intensity Crystal index Neutron_ID Position Position Position Velocity Velocity Velocity Time_Of_Flight Monitor (Square).
Monitor_nD: version $Revision$ with options=user1,n,x,y,z,vx,vy,vz,t,list all neutrons verbose
Monitor_nD: Collimator_in is a Intensity Crystal index Neutron_ID Position Position Position Velocity Velocity Velocity Time_Of_Flight Monitor (Square).
Monitor_nD: version $Revision$ with options=user1,n,x,y,z,vx,vy,vz,t,list all neutrons verbose
Monitor_nD: Collimator_out is a Intensity Crystal index Neutron_ID Position Position Position Velocity Velocity Velocity Time_Of_Flight Monitor (Square).
Monitor_nD: version $Revision$ with options=user1,n,x,y,z,vx,vy,vz,t,list all neutrons verbose

Trace ETA (single process) 1.27806 [h]
0 %
10 %
20 %
30 %
40 %
50 %
60 %
70 %
80 %
90 %

# 3.5.24, git: [pid 95430] Signal 11 detected SIGSEGV (Mem Error)
# Simulation: BMSPEC_Coll (BMSPEC_parallelBeam_3.35_2.0_xtal15.instr)
# Breakpoint: [_Crystal_15_out_trace] component Crystal_15_out=Monitor_nD() TRACE [/Applications/McStas-3.5.24.app/Contents/Resources/miniconda3/share/mcstas/resources/monitors/Monitor_nD.comp:403] 0.00 % ( 0.0/5000000000.0)
# Date: Thu May 1 10:24:24 2025
# Started: Thu May 1 09:18:16 2025
# Last I/O Error: No such file or directory
INFO: call to ./BMSPEC_parallelBeam_3.35_2.0_xtal15.out failed with Command './BMSPEC_parallelBeam_3.35_2.0_xtal15.out --trace=0 --ncount=5000000000.0 --dir=/Users/cwl/boxColl_parallelBeams_dE_xtal_15_HiQ/BMSPEC_parallelBeam_3.35_2.0_xtal15_20250501_091816 --format=McCode --bufsiz=10000000 E_0=3.35 delta_E=2 sample_pos=65 sample_size=0.005 xtal_target_wdth=0.08 xtal_target_hght=0.06 mos=60 collDiv=5 twoThetaTotal=112.797 signalConeAngle=40 zMin=1.5 zMax=2.3 crystalLength=0.07 crystLenScale=1 accTheta=0.001 detOffsetX=2.2 detOffsetZ=2.229 energyLoss=0 excWidth=0' died with <Signals.SIGQUIT: 3>.
Traceback (most recent call last):
File "/Applications/McStas-3.5.24.app/Contents/Resources/miniconda3/share/mcstas/tools/Python/mcrun/mcrun.py", line 612, in <module>
main()
File "/Applications/McStas-3.5.24.app/Contents/Resources/miniconda3/share/mcstas/tools/Python/mcrun/mcrun.py", line 584, in main
mcstas.run() # in mccode.py
^^^^^^^^^^^^
File "/Applications/McStas-3.5.24.app/Contents/Resources/miniconda3/share/mcstas/tools/Python/mcrun/mccode.py", line 341, in run
return self.runMPI(args, pipe, override_mpi)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Applications/McStas-3.5.24.app/Contents/Resources/miniconda3/share/mcstas/tools/Python/mcrun/mccode.py", line 395, in runMPI
return Process(binpath).run(args, pipe=pipe)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Applications/McStas-3.5.24.app/Contents/Resources/miniconda3/share/mcstas/tools/Python/mcrun/mccode.py", line 77, in run
raise err
File "/Applications/McStas-3.5.24.app/Contents/Resources/miniconda3/share/mcstas/tools/Python/mcrun/mccode.py", line 73, in run
proc = run(command, shell=True, check=True, text=True, capture_output=pipe)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Applications/McStas-3.5.24.app/Contents/Resources/miniconda3/lib/python3.12/subprocess.py", line 573, in run
raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command './BMSPEC_parallelBeam_3.35_2.0_xtal15.out --trace=0 --ncount=5000000000.0 --dir=/Users/cwl/boxColl_parallelBeams_dE_xtal_15_HiQ/BMSPEC_parallelBeam_3.35_2.0_xtal15_20250501_091816 --format=McCode --bufsiz=10000000 E_0=3.35 delta_E=2 sample_pos=65 sample_size=0.005 xtal_target_wdth=0.08 xtal_target_hght=0.06 mos=60 collDiv=5 twoThetaTotal=112.797 signalConeAngle=40 zMin=1.5 zMax=2.3 crystalLength=0.07 crystLenScale=1 accTheta=0.001 detOffsetX=2.2 detOffsetZ=2.229 energyLoss=0 excWidth=0' died with <Signals.SIGQUIT: 3>.

It looks like it running just fine til the end but then throws a ‘died with <Signals.SIGQUIT: 3’  …

Any suggestion what I could/should try?

If a code snippet would help I can try to provide it but the error message suggests to me it is something different…

Thanks folks,

Uli

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Peter Kjær Willendrup
Forskningsingeniør, Specialkonsulent

DTU Physics

Technical University of Denmark

[cid:e108e480-fcab-46e2-9531-b38165079572 at win.dtu.dk]

Department of Physics
Fysikvej
Building 307
DK-2800 Kongens Lyngby

Main office at
ESS DMSC
Building 305
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Direct +45 2125 4612
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pkwi at fysik.dtu.dk

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