The paper describes a parallel-I/O extension of the Universal Access Layer, a multi-language interface used for exchange of standardized data objects between Integrated Tokamak Modeling (ITM) codes. ...Although our evaluation focuses on Lustre, the general idea also applies to other parallel file systems. A snapshot of the current implementation is given, followed by an analysis of user and system requirements. The design derived from the serial version of the UAL is described, and emphasized features such as the ability to choose between serial and parallel I/O are explained. Performance tests comparing the implementation to other I/O methods are made to analyze the impact of the implementation. The outcome shows that the new implementation not only enables the I/O of datasets with several GB in size but also speeds up the write rate by a factor of 13 in the best case.
To operate advanced plasma scenario (long pulse with high stored energy) in present and future tokamak devices under safe operation conditions, the control requirements of the plasma control system ...(PCS) leads to the development of advanced feedback control and real time handling exceptions.
To develop these controllers and these exceptions handling strategies, a project aiming at setting up a flight simulator has started at CEA in 2009. Now, the new WEST (W Environment in Steady-state Tokamak) project deals with modifying Tore Supra into an ITER-like divertor tokamak. This upgrade impacts a lot of systems including Tore Supra PCS and is the opportunity to improve the current PCS architecture to implement the previous works and to fulfill the needs of modern tokamak operation.
This paper is dealing with the description of the architecture of WEST PCS. Firstly, the requirements will be presented including the needs of new concepts (segments configuration, alternative (or backup) scenario, …). Then, the conceptual design of the PCS will be described including the main components and their functions.
The third part will be dedicated to the proposal RT framework and to the technologies that we have to implement to reach the requirements.
•We propose an overview of the future control system of the Tore Supra in WEST configuration.•The control system will be based on DCS (Discharge Control System) of ASDEX Upgrade.•The Pulse Schedule ...Editor will be based on the experiment program editor of the future W7X facility.•The operation of this new system is illustrated by an example based on a simple plasma current/loop voltage control.
The configuration of the Tore Supra WEST project leads to control challenges and event handling close to those of ITER from a plasma scenario point of view (X-point configuration, H mode, long duration pulse) and from a machine protection point of view (metallic environment). Based on previous conceptual studies and to meet the WEST requirements, a sub-project will implement a new plasma control system (PCS) and a new pulse schedule editor (PSE). The main idea is to use a segment approach to describe the pulse scheduling with a full integration of event handling both on the PCS and on the PSE. After detailed specification work, it has been shown that the real-time framework called DCS (Discharge Control System) which is currently used on ASDEX upgrade fulfills the requirements and could be integrated into the WEST global control infrastructure. For the PSE, the Xedit tool, developed for the future W7X facility, has been chosen. This contribution will begin by a short explanation of the concepts proposed for the control of the plasma and the handling of events during the plasma discharge. Then it will focus on the new centralized architecture of the new Tore Supra PCS and an operating principle example showing the efficiency of the approach to handle normal and off-normal events. This later point will illustrate the required modifications of DCS and Xedit to fit with the Tore Supra Control infrastructure.
► We developed a software tool that converts a physics code to a Kepler actor. ► The actor runs the codes on a remote supercomputer or a grid. ► The complexity is hidden from the user. ► We present ...the first workflows that use actors generated by the proposed tool.
Fusion Modelling and Simulation are very challenging and the high performance computing issues are addressed here. Based on the framework developed by the European Integrated Tokamak Modelling project and on the EUFORIA infrastructure, a tool solving nicely these difficulties has been developed for the end users and applied to several fusion simulation cases. The first part recalls the issues with GRID and high performance computing, while the second part presents the solutions and the tool for developing easily a GRID/HPC actor. The last part reports the use of this tool in MHD equilibrium and plasma edge simulations.
The operation of present day tokamak and future machine like ITER is more and more demanding in terms of plasma control both for increasing plasma performance, stability and ensuring machine ...protection. Additionally saving experimental time by validating the pre-programmed plasma scenario through a simulator is also of major importance. These issues highlight the necessity to build new tools such as a generic multipurpose plasma discharge flight simulator. Such a project has been recently started at CEA and is based on the integrated tokamak modeling task force formalism and simulation platform. The paper reports on the present status of the project, reviewing in particular the needs for new tool development, the architecture of the generic multipurpose tokamak plasma discharge flight simulator, with the different software/hardware interfaces. A first test case of this tool in the “full simulation” modes and using the European simulation platform is discussed.
The EFDA task force on Integrated Tokamak Modelling (ITM-TF) is providing the EU fusion community with a complete and flexible suite of reliable software tools and codes able to simulate the next ...ITER and DEMO plasma discharges. EFDA has launched the Gateway project as the first computing facility to be jointly used by EU fusion associations.
The Gateway has been designed to allow the ITM-TF members to work together on a common platform and share their codes, developments tools and technologies as well as to make able the inter-operation with tera-scale supercomputer facilities. Technically the Gateway is a rather small high computing facility in operation since 2008, with 1
Teraflops of theoretical peak and 100
Terabytes shared storage area for experimental and simulation data.
This paper describes the information technologies involved in the Gateway facility, particularly as regards the low latency interconnect network for multi-core platform as well as fast I/O solutions implemented with storage over Infiniband and high performance parallel file systems. The solutions adopted on the Gateway facility had undergone to specific benchmarks showing excellent performances in typical fusion data handling issues. Finally the interoperability between Gateway and ENEA CRESCO supercomputer will be described showing the access solutions that allow the exploitation of tera-scale supercomputer facilities.
The feedback control of fusion experiments in tokamak devices is entering a new area driven by the increase of control requirements for obtaining burning plasmas under safe operation conditions. A ...project aiming at setting up a flight simulator for the development of advanced controllers has started last year at CEA. This simulator will reuse most of the components of the European Integrated Tokamak Modelling (ITM) simulation platform. Thus, it will benefit from the development made by the task force and it will be able to offer a development platform for the new controllers of present day European tokamaks and future machines. This paper provides an overview of the architecture of the simulator. The functional specifications of the simulator have been defined and the needs in interface implementation are analysed as well.
The Integrated Tokamak Modelling (ITM) Task Force aims at providing a suite of codes for preparing and analyzing future ITER discharges. In the framework of the ITM, the universal access layer (UAL) ...provides the capability of storing and retrieving data involved in simulation. The underlying data structure is hierarchical and the granularity in data access is given by the definition of a set of consistent physical objects (CPOs). To describe the data structure of the overall ITM database, the XML schema description (XSD) has been used. Originally intended to describe the structure of XML documents, XSD is used here to provide an unambiguous way of describing how data are structured, regardless of the actual implementation of the underlying database.
The MDSplus-based UAL implementation is currently under test and other prototypes for investigating alternative data storage systems are foreseen.
Fusion Modelling and Simulation are very challenging and the High Performance Computing issues are addressed here. Toolset for jobs launching and scheduling, data communication and visualization have ...been developed by the EUFORIA project and used with a plasma edge simulation code.
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