[SI-LIST] Re: Getting Hspice to accept numbers with mantissa' s larger than 8 characters
- From: "Andrew Ingraham" <a.ingraham@xxxxxxxx>
- To: <si-list@xxxxxxxxxxxxx>
- Date: Thu, 6 Apr 2006 11:11:52 -0400
Taha wrote:
> Any thoughts on this statement and how to test it's validity would
> greatly be apprecaited.
How to test its validity? The best answer is to do what at least one person
already suggested: Ask Synopsys! Keep asking them, until you get the
answers you need. It is their program, after all, and you're paying them to
support it. While asking us on this maillist may give an interesting array
of responses, experiences, and guesses, none of us know HSpice as well as
the people at Synopsys do.
Muranyi wrote:
> However, regarding the validity of your question, I wonder what
> is the value of having that many digits as input to an iterative
> solver where the solutions are inherently not exact?
I could be wrong, but I think SPICE's solver is not iterative and is exact
(well, within the limits of numerical accuracy) in the special case when the
network being simulated contains no nonlinear elements.
When all elements are linear, SPICE finds the (exact?) solution in one pass;
and I believe that if you look at the stats, the number of Newton Iterations
isn't even one, it's zero. It's not that the correct solution "falls out"
from the first pass, it's that SPICE takes a totally different algorithm
when there are no nonlinearities, and doesn't need to iterate even once.
(Of course it is only as accurate as its math routines. Nothing's perfect.)
Still, however, I question the validity of expecting double precision
accuracy. I don't know precisely what you're up to, though.
Regards,
Andy
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
