论文标题
通过三重态搜索:有效的本地轨道重建算法并行体系结构
Search by triplet: An efficient local track reconstruction algorithm for parallel architectures
论文作者
论文摘要
每秒在LHCB探测器上碰撞数百万个颗粒,位于CERN的大型强子对撞机内。由于这些碰撞而产生的颗粒通过各种检测设备,到2021年将产生高达40 TBP的原始数据速率。这些数据将通过数据采集系统馈送,该数据采集系统可重建单个颗粒并实时过滤碰撞事件。这个过程将在一个异质农场中使用,该农场使用专门的CPU和GPU硬件,在两个阶段的过程中被称为“高级触发器”。 物理探测器中带电颗粒轨迹的重建(也称为轨道重建或跟踪)确定粒子通过检测器时的位置,电荷和动量。顶点定位器子探测器(VELO)是距离梁线的最接近的检测器,位于LHCB磁体产生相当大的磁场的区域外。它用于重建直颗粒轨迹,这些轨迹是重建其他子检测器并定位碰撞顶点的种子。 Velo子探测器将每秒检测到多达1000万个颗粒,需要在高级触发器中实时重建。 我们提出了Triplet的搜索,Triplet是一种有效的轨道重建算法。我们的算法旨在跨平行体系结构有效运行。我们扩展了以前的工作,并解释了自成立以来的算法演变。我们在各种情况下显示了算法的缩放,并在其每个组成部分的复杂性方面分析了其摊销时间,并介绍了其性能。我们的算法是SIMT体系结构上Velo Track重建的当前最新算法,我们鉴定了其对先前结果的改进。
Millions of particles are collided every second at the LHCb detector placed inside the Large Hadron Collider at CERN. The particles produced as a result of these collisions pass through various detecting devices which will produce a combined raw data rate of up to 40 Tbps by 2021. These data will be fed through a data acquisition system which reconstructs individual particles and filters the collision events in real time. This process will occur in a heterogeneous farm employing exclusively off-the-shelf CPU and GPU hardware, in a two stage process known as High Level Trigger. The reconstruction of charged particle trajectories in physics detectors, also referred to as track reconstruction or tracking, determines the position, charge and momentum of particles as they pass through detectors. The Vertex Locator subdetector (VELO) is the closest such detector to the beamline, placed outside of the region where the LHCb magnet produces a sizable magnetic field. It is used to reconstruct straight particle trajectories which serve as seeds for reconstruction of other subdetectors and to locate collision vertices. The VELO subdetector will detect up to 1000 million particles every second, which need to be reconstructed in real time in the High Level Trigger. We present Search by triplet, an efficient track reconstruction algorithm. Our algorithm is designed to run efficiently across parallel architectures. We extend on previous work and explain the algorithm evolution since its inception. We show the scaling of our algorithm under various situations, and analyze its amortized time in terms of complexity for each of its constituent parts and profile its performance. Our algorithm is the current state-of-the-art in VELO track reconstruction on SIMT architectures, and we qualify its improvements over previous results.