CHEP 2019

Abstracts

Efficient Iterative Calibration on the Grid using iLCDirac

• Speaker: Andre Sailer
• Authors: Oleksandr Viazlo, Andre Sailer
• Status: accepted
• Track 3: Middleware and Distributed Computing (Oral)
• Abstract: Software tools for detector optimization studies for future experiments need to be efficient and reliable. One important ingredient of the detector design optimization concerns the calorimeter system. Every change of the calorimeter configuration requires a new set of overall calibration parameters which in its turn requires a new calorimeter calibration to be done. An efficient way to perform calorimeter calibration is therefor essential in any detector optimization tool set. In this contribution, we present the implementation of a calibration system in iLCDirac, which is an extension of the DIRAC grid interware. Our approach provides more direct control over the grid resources to reduce overhead of file download and job initialisation, and provides more flexibility during the calibration process. The service controls the whole chain of a calibration procedure, collects results from finished iterations and redistributes new input parameters among worker nodes. A dedicated agent monitors the health of running jobs and resubmits them if needed. Each calibration has an up-to-date backup which can be used for recovery in case of any disruption in the operation of the service. As a use case, we will present a study of optimization of the calorimetry system of the CLD detector concept for FCC-ee, which has been adopted from the CLICdet detector model. The detector has been simulated with the DD4hep package and calorimetry performance have been studied with the particle flow package PandoraPFA.
• Slides

DD4hep: a community driven detector description tool for HEP

• Speaker: Frank-Dieter Gaede
• Authors: Markus Frank, Frank-Dieter Gaede, Marko Petric, Andre Sailer
• Status: accepted
• Track 2: Offline Computing (Oral)
• Abstract: Detector description is an essential component in simulation, reconstruction and analysis of data resulting from particle collisions in high energy physics experiments and for the detector development studies for future experiments. Current detector description implementations of running experiments are mostly specific implementations. DD4hep is an open source toolkit created in 2012 to serve as a generic detector description solution. The main motivation behind DD4hep is to provide the community with an integrated solution for all these stages and address detector description in a broad sense, including the geometry and the materials used in the device, and additional parameters describing e.g. the detection techniques, constants required for alignment and calibration, description of the readout structures and conditions data. In this presentation, we will give an overview of the project and discuss recent developments in DD4hep as well as showcase adaptions of the framework by LHC and upcoming accelerator projects together with the roadmap of future developments. We will describe the DDG4 component of DD4hep, which is a powerful tool that converts arbitrary DD4hep detector geometries to Geant4 and gives access to all Geant4 action stages, including an overview of its comprehensive plugin suite that includes handling of different IO formats, Monte Carlo truth linking and a large set of segmentation and sensitive detector classes, allowing the simulation of a wide variety of detector technologies. We will further describe DDCond and DDAlign, which expose a mechanism to manage multiple versions of detector conditions data simultaneously and efficiently.
• Slides

DIRACOS: a cross platform solution for grid tools

• Speaker: Christophe Haen
• Authors: Ben Couturier, Christophe Haen, Marko Petric
• Status: accepted
• Track 3: Middleware and Distributed Computing (Oral)
• Abstract: DIRACOS is a project aimed to provide a stable base layer of dependencies, on top of which the DIRAC middleware is running. The goal was to produce a coherent environment for grid interaction and streamline the operational overhead. Historically the DIRAC dependencies were grouped in two bundles; Externals containing Python and standard binary libraries, and the LCGBundle which contained all grid-related libraries (gfal, arc, etc). Such a setup proved difficult to test and hindered agile development. DIRACOS solves the binary incompatibility that was caused by using a python version newer than the native system one (SLC6). It is spawned form a single list of required packages from where we use SRPMs to pull all dependencies down to the level of glibc. With such an approach we can provide the same packages for our clients, servers, and several platforms. It is an extendible setup with an DevOps development cycle in mind. The core build functionality of DIRACOS is based on Fedora Mock. DIRACOS also introduces its own grammar, to handle specific cases and it also allows patching (some SRPM require tweeking, which the user can do by providing a diff) as well as routines for pre/post/instead actions of compilation. With this approach DIRAC was able to provide a single bundle for clients and servers, that is reliable, flexible, easy to test and relatively small (250 MB). It allows for a smooth transition from SLC6 to CC7 and provides a clear roadmap for possible extension of DIRAC to a wide variety of platforms
• Slides

Towards a Turnkey Software Stack for HEP Experiments

• Speaker: Andre Sailer
• Status: accepted
• Track 2: Offline Computing (Oral)
• Abstract: Future HEP experiments require detailed simulation and advanced reconstruction algorithms to explore the physics reach of their proposed machines and to design, optimise, and study the detector geometry and performance. To synergise the development of the CLIC and FCC software efforts, the CERN EP R&D road map proposes the creation of a "Turnkey Software Stack", which is foreseen to provide all the necessary ingredients, from simulation to analysis, for future experiments, beyond CLIC, or FCC to proposed Super-tau-charm factories, CEPC or ILC. The software stack will facilitate writing specific software for experiments ensuring coherency and maximizing re-use of established packages to benefit from existing solutions and community developments, for example, ROOT, Geant4, DD4hep, Gaudi and PODIO. As a showcase for the software stack, the existing CLIC reconstruction software, written for iLCSoft, is being to be ported to Gaudi. In parallel, the back-end of the LCIO event data model can be replaced by an implementation in PODIO. These changes will enable the sharing of the algorithms with other users of the software stack. We will present the current status and plans of the turnkey software stack, with a focus of the adaptation of the CLIC reconstruction chain to Gaudi and PODIO, and detail the plans for future developments to generalize their applicability to FCC and beyond.
• Slides