Erros leading to a run stop without any geometry error shown

Geometry and Materials
1

Hello, I am struggling with a simulation.

The .log file shows the following message:

STOP TOO MANY ERRORS IN GEOMETRY: STOP
Note: The following floating-point exceptions are signalling: IEEE_UNDERFLOW_FLAG IEEE_DENORMAL
STOP STOP: FLUKA ABORTED

But, in Flair, the geometry does not indentify any problem… The .inp file is attached.

Thank you in advance for your help :slight_smile:

.

Kind Regards,

Duarte

Simulacoes_Galaviz_fibra1.inp (69.5 KB)

3

Dear Duarte,

The problem is related to the processing of the geometry by FLUKA. Since your simulation geometry contains rather small features (such as a 10 microns fibre cladding), I would advise that you reduce the the “absolute accuracy parameter” of the GEOBEGIN card:

GEOBEGIN                1.0E-8                                        COMBNAME

The default value is 0.0001 and I managed to run your simulation using 1.0E-8. You could however still have problems despite this fix. Your geometry features many cylinders which meet in only one line of points. This could lead to accuracy errors. I suggest you space out the cylinders by a small amount to leave a well defined gap in between. The gap could be of the order of 0.1 microns, and it would not have any noticeable impact on your simulation results, but those results would be more consistent and running would be more stable.

4

Thank you. I will try this and then give you some feedback

Kind Regards,
Duarte

5

Hello, Benoit,

It solved the problem.

Thank you!

Kind Regards,
Duarte