E s c o m m a

This is a circuit simulator that was derived in an attempt to write a set of math routines to solve linear and non-linear numerical problems. The netlist parser is continually being improved as well as the math routines. It's current state has facilities for LU decomposition and operating point analysis. The downloadable version is a bit delayed compared to the local copy because there is some of experimenting being done before any changes are released. It is written in C and protyping of some of the routines are tested under octave and maxima. This is released under the General Public License (GPL) for everyone to enjoy and learn from.

Tools

In the study of circuit simulation internals and numerical analysis, this tools provided insights on how a certain set of code reacts to certain type of data.

Octave - (www.octave.org) "GNU Octave is a high-level language, primarily intended for numerical computations. It provides a convenient command line interface for solving linear and nonlinear problems numerically, and for performing other numerical experiments using a language that is mostly compatible with Matlab. It may also be used as a batch-oriented language."

Maxima - (maxima.sourceforge.net) "Maxima is a descendant of DOE Macsyma, which had its origins in the late 1960s at MIT. It is the only system based on that effort still publicly available and with an active user community, thanks to its open source nature. Macsyma was the first of a new breed of computer algebra systems, leading the way for programs such as Maple and Mathematica."

Valgrind - (valgrind.kde.org) "Valgrind is a GPL'd system for debugging and profiling x86-Linux programs. With the tools that come with Valgrind, you can automatically detect many memory management and threading bugs, avoiding hours of frustrating bug-hunting, making your programs more stable. You can also perform detailed profiling, to speed up and reduce memory use of your programs."

References

• Simulators
  • Ngspice - The ngspice is a highly improved version of the original Berkeley code spice3f5. A lot of the bugs has been fixed and has become very stable even when used in a scripting environment and optimization like tclspice. This is used to verify the results of escomma calculation. It is part of the geda project which is a set of completely opensource EDA applications.
  • Gnucap - Gnucap is another opensource circuit simulator capable of DC, AC and Transient analysis. Unlike ngspice this is not based on the Berkeley source and is released under GPL.
  
  
• Links
  • Erik Cheeve, Analysis of Resistive Circuits, http://www.swarthmore.edu/NatSci/echeeve1/Ref/mna/MNA1.html
  • Spice Opus, Scientific Papers http://fides.fe.uni-lj.si/spice/papers/papers.html
  • GEDA, GPL Electronic Design and Automation, http://www.geda.seul.org
  
  
• Papers and Publication
  • [ 1 ] Albert Tatum Davis, Doctoral Dissertation "Implicit Mixed-Mode Simulation of VLSI Circuits" 1991
  • [ 2 ] Amit Mehrotra, "Numerical Analysis of Electronic Circuits"
  • [ 3 ] James F. Epperson, "An Introduction to Numerical Methods and Analysis" ISBN 9971-51-419-2