High Performance Electrical Modeling and Simulation (HPEMS) Project Statement

With the elimination of underground nuclear testing and declining defense budgets, science-based stockpile stewardship requires increased reliance on high performance modeling and simulation of weapon systems. Electrical systems and components are major elements in today’s weapon systems. The present electrical modeling and simulation capabilities are very limited and will be significantly expanded by using massively parallel computational resources. Our vision is to accurately characterize nuclear weapon electrical systems from first principles in all environments over a 50-year lifetime. The goal of this project is to provide the tools that will allow the use of massively parallel modeling and simulation techniques on high performance computers in existing and future nuclear weapon electrical systems models.

The Xyce™ Project

The Xyce™ project is a part of a larger HPEMS project at Sandia designed to meet and engage with the current and future needs of the weapons designers. It will provide a circuit modeling tool for Sandia designers capable of running efficiently on high-performance parallel computers using state-of-the-art algorithms. Some goals of this project are to

• Support Sandia-specific circuit models
• Include a consistent designer interface
• Produce an efficient parallel implementation on a variety of architectures
• Implement improved, scalable algorithms addressing SPICE convergence problems
• Couple to device (PDE) and other simulation codes

Xyce™ Overview

The Xyce™ Parallel Electronic Simulator development has focused on improving the capability over the current state-of-the-art in the following areas:

• Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). Note that this includes support for most popular parallel and serial computers.
• Improved performance for all numerical kernels (e.g., time integrator, linear solver) through state-of-the-art algorithms and novel techniques.
• Support for modeling circuit phenomena at a variety of abstraction levels (device, analog, digital and mixed-signal) in a rigorous and tightly coupled manner, allowing for timely, full-system solutions.
• A client-server or multi-tiered operating model, wherein the numerical kernel can operate distinct from the simulation interface (GUI).
• Object-oriented code design and implementation using modern coding-practices that ensure that the Xyce™ Parallel Electronic Simulator will be maintainable and extensible far into the future.

The code is a parallel code in the most general sense of the phrase – a message passing parallel implementation – which allows it to run efficiently on the widest possible number of computing platforms. These include serial, shared-memory and distributed-memory parallel as well as heterogeneous platforms. Furthermore, careful attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved even as the number of processors grows.

As mentioned above, the Xyce™ Parallel Electronic Simulator is being developed in support of electrical designers of Sandia National Laboratory and, as such, is implementing several novel features that will make their job considerably easier. In addition to allowing the simulation of circuits of unprecedented size, novel approaches to critical numerical kernels such as improved time-stepping algorithms and controls, better convergence of the nonlinear solver and improved device models. This approach aims to minimize the amount of simulation “tuning” required on the part of the designer and facilitate the code’s successful usage.