In September 2013, the large laser-based inertial confinement fusion device housed in the National Ignition Facility at Lawrence Livermore National Laboratory, was widely acclaimed to have achieved a milestone in controlled fusion – successfully initiating a reaction that resulted in the release of more energy than the fuel absorbed. Despite this success, we remain some distance from being able to create controlled, self-sustaining fusion reactions. Inertial Confinement Fusion (ICF) represents one leading design for the generation of energy by nuclear fusion. Since the 1950s, ICF has been supported by computing simulations, providing the mathematical foundations for pulse shaping, lasers, and material shells needed to ensure effective and efficient implosion.\ud\udThe research presented here focuses on one such simulation code, EPOCH, a fully relativistic particle-in-cell plasma physics code, developed by a leading network of over 30 UK researchers. A significant challenge in developing large codes like EPOCH is maintaining effective scientific delivery on successive generations of high-performance computing architecture. To support this process, we adopt the use of mini-applications – small code proxies that encapsulate important computational properties of their larger parent counterparts. Through the development of a miniapp for EPOCH (called miniEPOCH), we investigate known timestep scaling issues within EPOCH and explore possible optimisations: (i) Employing loop fission to increase levels of vectorisation; (ii) Enforcing particle ordering to allow the exploitation of domain specific knowledge and, (iii) Changing underlying data storage to improve memory locality. When applied to EPOCH, these improvements represent a 2.02× speed-up in the core algorithm and a 1.55× speed-up to the overall application runtime, when executed on EPCC’s Cray XC30 ARCHER platform.
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机译:2013年9月,劳伦斯·利弗莫尔国家实验室(Lawrence Livermore National Laboratory)的国家点火装置中安装的大型基于激光的惯性约束聚变设备得到了广泛认可,在受控聚变方面取得了里程碑式的成就–成功地引发了反应,释放出的能量超过吸收的燃料。尽管取得了成功,但我们离创建可控的,自我维持的聚变反应还有一段距离。惯性约束聚变(ICF)代表了一种通过核聚变产生能量的领先设计。自1950年代以来,ICF得到了计算仿真的支持,为确保有效和高效内爆所需的脉冲整形,激光和材料外壳提供了数学基础。\ ud \ ud此处介绍的研究重点是这样一种仿真代码EPOCH,由30多个英国研究人员组成的领先网络开发的完全相对论的单元内粒子等离子体物理代码。开发像EPOCH这样的大代码所面临的一项重大挑战是如何在下一代高性能计算体系结构上保持有效的科学交付。为了支持此过程,我们采用了小型应用程序-小型代码代理,封装了较大的父级对等应用程序的重要计算属性。通过开发用于EPOCH的miniapp(称为miniEPOCH),我们研究了EPOCH中已知的时间步长缩放问题,并探索了可能的优化方法:(i)利用循环裂变增加矢量化水平; (ii)强制执行粒子排序以允许利用特定领域的知识,以及(iii)更改基础数据存储以改善内存局部性。当应用于EPOCH时,这些改进表示在EPCC的Cray XC30 ARCHER平台上执行时,核心算法的速度提高了2.02倍,整个应用程序运行时间的速度提高了1.55倍。
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机译:用等离子体约束实现重力场的动态控制热核聚变(TLTS)方法,通过热辐射等离子体绝缘的壁反应堆防止中子辐射并节省磁场和等离子体的混合,使用旋转磁场的异步磁惯性约束反应堆(AMITYAR和HFM)为实施该方法,在该反应器中点燃热核反应的方法,爆炸式等离子发生器(VIP)的实施方法,以及具有HFM的特立普安瓿,以实现D + T反应和具有超高温热度的HFM D +3НЕ和1Н+11В的高温反应