New Multiprocessor SPICE Breaks The Speed Barrier

Product:    New Multiprocessor Version of SPICE
Description:  Analog and mixed signal circuit design software
              available from Intusoft
Price:        Base price (1 CPU - x86, Alpha, MIPS platforms)
              for ICAP/4Windows, which includes IsSpice5x $2595,
              Base price (1 CPU - Sun platform) for IsSpice5x $2995,
              Price increases based on the number of additional CPUs
Availability: 3rd Quarter 1995
Platform:     Windows95, Windows NT (x86, Digital Alpha, and MIPS),
              and Sun (Solaris)

Intusoft has developed a multithreaded, multiprocessor version of its
popular native analog and mixed mode circuit simulation program. The new
simulator, called ISSPICE5X, is able to simulate circuits with a linear
increase in speed per additional processor. This allows users to nearly
double the speed of their simulations simply by adding another processor
to their system. Several new partitioning algorithms have been added to
the current version, IsSpice4, in order to support multiprocessor
operation. Windows NT and Sun platforms with multiple CPUs are able to
take advantage of the multiprocessor capability without the need for any
additional software or hardware. However, ISSPICE5X is also multithreaded,
so Windows95 is able to run the new simulator with substantial speed
improvements. At the Design Automation Conference Intusoft will display
dual or quad processor 486, Pentium, Alpha, and Sun machines in a SPICE
simulation run-off. Benchmark circuits from the Microelectronics Center of
North Carolina (ftp:mcnc.org) will be used.

The main portions of the Newton-Raphson algorithm, namely the model
evaluation and load, and sparse-matrix solution have been parallelized in
ISSPICE5X. The simulator starts by partitioning the circuit in a binary
tree structure. The depth of the tree can be selected based on the number
of available processors. The circuit is partitioned with Intusoft's
proprietary iterative mincut heuristic algorithm.

There are three basic analysis types in ISSPICE5X: AC, DC, and transient.
AC analysis is the easiest to parallelize since the solution at each
frequency is independent. By contrast DC and transient analyses are
iterative processes repeatedly performing the LOAD and SOLVE steps until
convergence is achieved. In the LOAD step the device model equations are
evaluated and the circuit Jacobian matrix is updated to set up a
non-symmetric sparse system of linear equations. In the SOLVE step the
equations from the previous step are solved using a sparse LU
decomposition followed by forward and backward substitution. It is not
unusual for the LOAD and SOLVE steps to take up to 90% of the total
simulation time. Intusoft has developed a proprietary algorithm that
parallelizes the execution of these two steps at each iteration resulting
in a significant (linear) decrease in the simulation time.

Each Newton-Raphson iteration is divided into tasks which are executed
serially or concurrently. Those tasks that are performed serially are said
to be in a single thread phase and the ones that are executed concurrently
are said to be in a multithread phase. In a multiprocessor environment,
each process in a multithread phase can be dynamically assigned to a
processor by the operating system. The operating system also provides the
necessary event flags used for the synchronization between processes. The
LOAD and SOLVE steps at each iteration are executed in a multithread
phase. In addition, at each iteration entire subcircuits (resulting from
the circuit partitioning) can be declared latent. Latent subcircuits do
not have to be processed for subsequent iterations until the latency
criteria is no longer satisfied. This means that even in a single thread
environment, such as Windows 95 ISSPICE5X will identify the latent
subcircuits and save a significant amount of LOAD time per iteration.

ISSPICE5X is a NATIVE mixed mode simulator with an event driven digital
simulator built into the SPICE core. The SPICE portion is based on U.C.
Berkeley SPICE 3F and XSPICE from Georgia Tech. IsSpice5x will be released
in the 3rd quarter 1995. The price for ISSPICE5X (standalone) is $2995 for
the Sun version (1 CPU). On Windows NT and Windows95 platforms the price
(as part of the ICAP/4 package) is $2595. The prices increase with the
number of CPUs utilized.

intusoft
PO Box 710
San Pedro, CA 90733-0710
310-833-0710,  fax 310-833-9658

 ============================================================
 From the  'New Product News'  Electronic News Service on....
 AOL (Keyword = New Products) & Delphi (GO COMPUTING PRODUCT)
 ============================================================
 This information was processed from data provided by the 
 company or author mentioned. For additional details, please 
 contact them directly at the address/phone number indicated.
 All trademarks are the property of their respective owners.
 ============================================================
 All submissions for this service should be addressed to:
 BAKER ENTERPRISES,  20 Ferro Dr,  Sewell, NJ  08080  U.S.A.
 Email: RBakerPC (AOL/Delphi), rbakerpc@delphi.com (Internet)
 ============================================================
