Same random orientation of detectors for different simulation runs

Hi all,

Allpix² allows to define a precision for the orientation and position of the detectors. I would like to simulate 50 runs with 20000 particles for each random geometry.

My question: is there a way to make Allpix² take the same detector position and orientation for all 50 runs?

Thanks in advance.


Hi @pietrodelta7

yes, via

random_seed_core = <your_fixed_seed>

This will seed the generator for random positions the same for all runs but use different seeds (via random_seed) for the simulations themselves.

We should probably document this more thoroughly. :slight_smile:


Thanks @simonspa ! Maybe a follow-up question: are there other functions of the software which are dependent on this parameter (random_seed_core)?

Hi @pietrodelta7

there is none. The parameter name is not very nice and stems from very early days of APSQ. But in the end we never needed any random numbers in core components apart from the misalignment feature.

We’ll update the documentation following this ticket:


Understood. Thanks again @simonspa !