Subject: [IBIS] A program for checking the derivatives
From: Al Davis (aldavis@ieee.org)
Date: Mon Oct 21 2002 - 18:22:09 PDT
I have said several times that checking the derivative of
tables will reveal problems, and have been asked how and what
tools do it.
Following is a simple program that I use to check the
derivatives. It takes an IBIS file as input, and produces an
output that looks like an IBIS file, but isn't. It has the
derivatives substituted for the tables.
You can get the second derivative by running its output through
the program again, and the third derivative by running that
through the program.
It is hereby placed in the public domain, and is provided
without any warranty of any kind. If it breaks, you get to
keep both pieces.
It is written in "awk", which is provided with most unix-type
systems. I tested it on Mandrake gnu/linux, using gawk 3.1.0 .
Now that you have the tool, PLEASE check the derivatives of any
IBIS file that you release to the public!!! If you really
care, check the second and third derivatives, too.
Here it is:
=====================================
#!/usr/bin/awk -f
/[a-df-zA-DF-Z|\*]/ {
d1=0;
d2=0;
d3=0;
d4=0;
print;
skip=1;
next;
}
{
if (skip) {
printf("%16g skip\n", $1);
skip=0;
}else{
dx = $1-d1;
printf("%-16g %-16g %-16g %-16g\n", $1, ($2-d2)/dx,
($3-d3)/dx, ($4-d4)/dx);
}
d1=$1;
d2=$2;
d3=$3;
d4=$4;
}
=====================================
-----------------------------------------------------------------
|For help or to subscribe/unsubscribe, email majordomo@eda.org
|with the appropriate command message(s) in the body:
|
| help
| subscribe ibis <optional e-mail address, if different>
| subscribe ibis-users <optional e-mail address, if different>
| unsubscribe ibis <optional e-mail address, if different>
| unsubscribe ibis-users <optional e-mail address, if different>
|
|or email a request to ibis-request@eda.org.
|
|IBIS reflector archives exist under:
|
| http://www.eda.org/pub/ibis/email_archive/ Recent
| http://www.eda.org/pub/ibis/users_archive/ Recent
| http://www.eda.org/pub/ibis/email/ E-mail since 1993
This archive was generated by hypermail 2b28 : Mon Oct 21 2002 - 18:29:57 PDT