FreeLists / si-list / [SI-LIST] Re: Getting Hspice to accept numbers with mantissa' s larger than 8 characters

["Taha Amiralli" <thamiral@xxxxxxxxx>]

Thanks for the response Patrick,

I had actually considered the option of building up a double precision
value using two parameters at one point in time (as soon as I had
learned that the simulation engine in hspice is double precision),
however, I am still unable to prove to myself that this method would
actually work.

Whats really interesting is that when I was browsing though the old
Hspice manual I came across the following Footnote:

"Star-Hspice uses double-precision numbers (15 digits) for
expressions, user-defined parameters, and sweep variables. For better
precision, use parameters instead of constants in algebraic
expressions, since constants are only single-precision numbers (7
digits)."
<http://www.ece.uci.edu/eceware/hspice_docs/hspice_and_qrg/hspice_2001_2-41=
.html>

I have actually been trying to look for that statement in the new
Hspice manuals, but I have not been able to find it.

Any thoughts on this statement and how to test it's validity would
greatly be apprecaited.

Thanks once again,

Sincerely,

-------------------
Taha Amiralli
thamiral [A] uwo [D] ca
thamiral [A] gmail [D] com

MESc Candidate 2007, Computer Engineering
The University Of Western Ontario

BESc, BSc. 2005,
Computer Engineering & Computer Science
The University Of Western Ontario
---------------------------------------------------------------




On 4/5/06, Zabinski, Patrick J. <zabinski.patrick@xxxxxxxx> wrote:
> Taha,
>
> Not sure if this will actually work or not (and
> not sure how I could validate it did work or fail),
> but could you work around the input limitation
> by adding a few numbers together?
>
> For example:
>
>      R1 n1 n2 res_value
>      .PARAM res1=3D6.838495e2
>      .PARAM res2=3D9.039344e-5
>      .PARAM res_value=3D'res1 + res2'
>
> Alternatively:
>
>      Ra1 n1 na 6.838495e2
>      Rb1 na n2 2=3D9.039344e-5
>
> Assuming the input is limited to single-precision
> and the internals are truly double-precision,
> would this approach work?  Or, would numerical
> round off during input-conversion kill it?
>
> Pat
>
> > Thanks for the response,
> >
> > Your analysis of the validity of my question is absolutely correct.
> >
> > My reasons for trying to get hspice to accept a double precision
> > constant is actually to try and debug an algorithm that I am
> > implementing.
> >
> > This algorithm has two transformation matrices (that are multiplied
> > toghether)  and I have noted that when I implement only one of these
> > transformation matrices, I get a correct simulation.
> >
> > The problems arise when I try to implement the product of these two
> > transformation matrices and these problems range from an incorrect
> > simulation to a 'time step too small' error. I have ruled out the
> > obvious errors (i.e. the matrices are incorrect) by prototyping this
> > algorithm in circuit simulator that I have written.
> >
> > Given all this, I was hoping that the source of the problem was that I
> > am giving hspice single precision numbers whilst my 'homemade' circuit
> > simulator is fed double precision numbers.
> >
> > By the way, Synopsys has switched to double precision numbers in the
> > simulation engine, however, it appears that they only read in single
> > precision numbers from the input spice file by default.
> >
> > Thanks once again,
> >
> > Sincerely,
> >
> ------------------------------------------------------------------
> 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:
> http://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:
>                 http://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
>
>
>


--
------------------------------------------------------------------
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:
http://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:     
                http://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