[fluka-discuss]: RE: Code version preference for cluster use

From: Chris Theis <Christian.Theis_at_cern.ch>
Date: Wed, 15 May 2019 15:19:28 +0000

Dear colleagues,

looking at the postings over the last year I see that this issue with the GFORTRAN version resurfaces regularly. Especially for those of us who need to maintain a large number of machines in a cluster, the upgrades continue to be a rather painful and expensive exercise. Looking at an e-mail by Alfredo from 18/1/2018:

"Attempts to run Fluka compiled with Gfotran 7.x on a machine running Gfortran 6.x and viceversa will fail with strange errors. Unfortunately it seems that every new Gfortran major version is
breaking compatibility with previous ones."

confirms that this is also difficult for the developers. As effective and indisputably elegant the method to distribute pre-compiled object files to allow for user-routines was more than 20 years ago, it undeniably shows the inherent problems related to compiler dependency. Dynamic shared objects have been around and well tested as the standard solution to this problem (of user plugins) in the IT sector for decades. Therefore, I wanted to ask if there are plans and maybe a time-frame to actually resolve this issue on the developer side?

As long as containers that can be used on clusters are not part of an official distribution they are not really a suitable solution to my mind. Neither is sticking with a FORTRAN77 compiler of which the development has stopped more than 10 years ago and which, for several years already, is not included anymore by any major Linux distribution that I'm aware of.

Best regards
Chris

-----Original Message-----
From: owner-fluka-discuss_at_mi.infn.it <owner-fluka-discuss_at_mi.infn.it> On Behalf Of Horváth Dávid
Sent: 14 May, 2019 11:13 AM
To: Primidis, Thomas <Thomas.Primidis_at_liverpool.ac.uk>; fluka-discuss <fluka-discuss_at_fluka.org>
Subject: [fluka-discuss]: Re: Code version preference for cluster use

Dear Thomas,

gfortran:
gfortran-7 support by FLUKA is expected to be dropped soon, as gfortran-9 has just been released, and FLUKA usually only supports the two latest releases.
gfortran-8 version should be available until gfortran-10 is released sometime in 2020.

You can compile gfortran from the source without admin rights (if the necessary tools are already installed). For more details see: https://wiki.osdev.org/Building_GCC

Docker:
The docker version of FLUKA is NOT suitable for clusters, as it requires admin rights to run. It is only intended for single user PCs.

g77:
The g77 version of FLUKA should be available in the long term.
Please note, depending on the OS of the cluster g77 may not be available.

There shouldn't be any meaningful difference in the results between the g77 and gfortran versions, but the gfortran one has an ~25-30% performance advantage.

I hope this helps.

Kind regards,
Dávid Horváth

Junior Researcher
Radiation Protection
ELI Beamlines

E: david.horvath_at_eli-beams.eu
T: +420 266 051 283
M: Za Radnicí 835, 25241 Dolní Břeľany, Czech Republic


________________________________________
From: owner-fluka-discuss_at_mi.infn.it <owner-fluka-discuss_at_mi.infn.it> on behalf of Primidis, Thomas <Thomas.Primidis_at_liverpool.ac.uk>
Sent: 13 May 2019 15:19:54
To: fluka-discuss
Subject: [fluka-discuss]: Code version preference for cluster use

Dear all,


I am using a 64-bit linux cluster to run my simulations and the administrators are reluctant to install newer versions of gfortran to support the new fluka distributions. They were kind enough to do this once for gfortran 6.4 but now I have to ask for a fresher installation.


Should I ask for a g77 since all distributions have a version with g77 compilation or should I ask for a gfortran-7, gfortran-8, docker?

What would be the difference in the simulation results/efficiency with these versions?


The point is to not have to ask for a 3rd time with the next fluka distributions.


Best regards,

Thomas


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Received on Wed May 15 2019 - 18:33:48 CEST

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