**Screamer: A Powerful Circuit Analysis Code**

Dr. Rick B. Spielman

Idaho
Accelerator Center

Idaho State University

Dr. Yury Gryazin

Mathematics Department

Idaho State University

Screamer is a fast, highly
optimized circuit-analysis code that was originally developed at Sandia
National Laboratories in 1985. Screamer is written in Fortran 77 (with some
extensions) and is highly optimized for speed. Screamer solves electrical
circuits having a limited, in-line circuit topology with restricted branches. This
restricted circuit topology allows for a very efficient matrix solver. We will
describe the mathematical basis for Screamer and show how our chosen topology
leads to a sparse matrix. We will describe the evolution of Screamer and show
how the development of powerful (> 0.1 TFlops) PCs with large amounts of
memory (> 8 GB) enabled major extensions to Screamer’s circuit topology.
Screamer incorporates many physics-based models such as dynamic loads, gas
switching, water switching, oil switching, magnetic switching, and vacuum
transmission lines, which are important to the high-voltage, pulsed-power
community. Additional circuit models or modifications to existing models can be
readily implemented in Screamer. We will show a sample problem run on Screamer.
Screamer runs on the Macintosh OS (9 & 10) and Windows 7 & 8 and is
available to users at no cost. We are always looking for new Screamer users who
might be interested in using and in supporting improvements to the code.
Screamer source code is available to users.