XPS: FULL: Emerging Nonvolatile Memory for Analog-iterative Numerical Methods

一种新型的计算机存储器--交叉点阻性存储器--已成为未来计算系统中取代当前存储器技术的可能候选者。这种存储器允许潜在的计算机设计具有高存储容量并且具有直接结合到处理单元中的存储器。为了开发这些新系统的潜力，需要对计算方法进行新的思考。这个项目将探索数值优化领域的新的、基本的方法，这些方法适合在包含交叉点电阻存储器的计算机系统上实现。优化领域被选为试验台，因为它对广泛的科学规律具有重要意义。交叉点存储器在容量和访问延迟方面具有前所未有的优势。要充分利用将内存集成到处理单元中的潜在好处，需要进行实质性的创新；目前的算法不适用，因为它们受到冯·诺伊曼瓶颈的限制。PIS将设计千兆级模拟迭代网络求解器(GAINS)，这是一种能够实现高效现场数据处理的系统架构。GAIN改变了应用级、架构级和逻辑/电路级的抽象，使每一层的设计人员和开发人员能够独立工作。(I)它将矩阵提升为一流数据类型。(Ii)它集成了计算和内存，避免了传统内存层次结构的缺陷。(3)它在存储和计算中利用了多值表示。(4)用多值模拟电路代替二值逻辑电路，降低了面积开销和功耗。PI将调查这种改变的范例对数值优化和机器学习中的算法设计的影响。

A new type of computer memory - crosspoint resistive memory - hasemerged as a likely candidate to replace current memory technology infuture computing systems. This memory allows for potential computerdesigns with high memory capacity and with memory incorporateddirectly into processing units. Novel thinking about computationalmethods is required to exploit the potential of these novelsystems. This project will explore new, fundamental methods in thefield of numerical optimization that are suited to implementation oncomputer systems that incorporate crosspoint resistive memory. Thefield of optimization is chosen as a testbed because of its importanceto a wide range of scientific disciplines.Crosspoint memory has unprecedented advantages in capacity and accesslatency. Substantial innovation is required to fully exploit thepotential benefits of integrating memory into processing units;current algorithms are unsuitable, because they are constrained by thevon Neumann bottleneck. The PIs will design the Gigascale Analog IterativeNetwork Solver (GAINS), a system architecture to enable efficientin-situ data processing. GAINS alters the application-, architecture-,and logic/circuit-level abstractions that enable designers anddevelopers at each layer to work independently. (i) It promotesmatrices to a first-class data type. (ii) It integrates computataionand memory, avoiding pitfalls of conventional memoryhierarchies. (iii) It exploits multi-valued representations in storageand computation. (iv) It replaces binary logic circuits withmulti-valued analog circuits, reducing area overhead and powerconsumption. The PIs will investigate the effects of this changed paradigmon the design of algorithms in numerical optimization and machinelearning.