after much discussion about the implementation. Since it is not
exactly clear what the field lines do at corners, the implementation
depends largely on an unknown and presumably global constant
multiplier; this has provisionally been set to 1 but needs to be
determined empirically with a field equation solver. At least one
rational approximation suggests a value of pi/2 instead of 1. The
corner capacitance can be considered a refinement of existing
parasitic capacitance extraction, and since it takes a non-trivial
additional amount of computation, it is left as an option to
"extract" that can be turned on when a more accurate result is
preferred at the expense of a longer extraction time.
(1) An incorrect use of ExtResetTiles() was found in "extresist"
which impacts performance, especially for small nets.
(2) Corrected units for resistance tolerance in extresist, and
handled output printing in fs when delay values get below ps
size.
(3) Added command option "extract do unique notopports" to be the
extraction option equivalent of the standalone command
"extract unique notopports".
(4) Changed the "extresist" default for "mindelay" to 1ps from 0,
in response to the observation that lumped resistance from
"extract" can be an extreme overestimate, and the extracted
time delay from "extesist" calculations should be used as a
better determination of whether a net should be output as a
resistor network or not.
(5) Added documentation for both "extract do unique notopports"
and the change to the "extresist" default values.
(1) Fixed an error that was introduced in version 8.3.590 with
a patch that should have been applied only for the case of
BJT devices, and not for MOSFETs. The patch will cause
devices generated by "device mosfet" or "device asymmetric"
to be read incorrectly from a .ext file during "ext2spice".
(2) Fixed an error in the tech file reading, where using CDL
parameters on a capacitor device would cause the tech file
loader to print an error message. The parsing was correct
and only the message should not have been printed.
(3) Added a new feature with the new command option "extract
do unique". This replaces the "extract unique" command by
running the same code within the extraction, but has the
additional effect of reverting the label changes afterward.
This prevents the user from inadvertently writing the
altered labels back to the database file.
the time the option was implemented), and also implemented (and
documented!) a similar command option "extract stepsize" for
reporting or changing the extraction step size.
unrelated nets to be captured in the same selection, due to the
use of the label bounding box instead of the label rectangle.
The bounding box is used for display only and should not be used
for connectivity.
with "extract do local" now being equivalent to "extract path .".
This allows extraction files to be put in a subdirectory and not
clog up the current working directory. Also: Fixed some behavior
around the use of "ext2spice -p <path>" so that it (1) works, and
(2) is compatible with the new "extract path". Since the ext2spice
and ext2sim commands are effectively independent of the primary
extraction, the "-p" option is needed to correspond to the use of
"extract path". Hopefully this is seen as only a minor inconvenience.
The website documentation now points to these contents in a clone
of the repository on opencircuitdesign.com, so all future edits of
the command-line documentation will be made directly to the git
repository. Also: Changed the precision of box values printed in
microns from 2 to 3 digits after the decimal place, so that 5 nanometer
grids do not get values clipped in the output.
R. Timothy Edwards