Hi, I'm Nick Chen, one of the teaching
assistants for Rob Rutenbar's VLSI CAD
Logic to Layout course.
This is the first tutorial in a series of
video tutorials introducing you to several
tools that you can use in this class.
The first tool that we will introduce is
KBDD.
Kbdd is a BDD calculator done by Professor
Randy Bryant's group at Carnegie Mellon
University.
This tutorial has an accompanying document
that you can refer to.
This document will be available on the
class website.
The example that we will be going through
today is the network repair example from
this document.
It's displayed here on the right hand side
of the screen.
The purpose of this video tutorial is not
to explain everything in that document,
but to show you how you can interface with
it to, through the web interface.
I've copied and pasted the KBDD com,
commands from the documents to this text
file.
As you can see I removed all the KBDD
prompts and just entered the commands as
is.
You can enter the commands in your
favorite text editor, save it and upload
it to the website.
Here's how you navigate to the tools
section.
I'm showing you our class website.
On the left-hand side of the screen you
can see the Programming Assignments tab.
And we click on it, and it brings me to
this Programming Assignments page.
Under the Tools section, you can find the
first tool that we've introduced, KBDD.
If you wish you can actually click, and
see the instructions that we have for this
particular assignment.
I'm not going to click on it now, but you
can do it, when you try the tool out for
yourself.
This programming assignment page will also
be populated with more programming
assignments for the course as the course
progresses.
What I'm going to do now is show you how
to actually submit the text file that we
have just saved.
You select the submit button here, choose
Output Submission and navigate to the file
that you just saved.
Click submit and you'll be presented with
a screen that says your submission has
been accepted and will be graded shortly.
Go back to the Programming Assignments
page.
After a few moments, if you click View,
you'll be able to see your results.
Here is our results.
You can see a submission time and you can
see a raw score.
As mentioned before in the announcement,
the raw score does not contribute towards
your final grade for this class.
Here's the feedback.
One thing that you may have noticed here
is that the first two lines where not
entered in your, in your text file.
What we have here is an additional command
that we alternately enter on our site.
Its purpose is to prevent canon scripts
from consuming too much memory on our back
end.
Basically, it tells and limits KBDD to how
much memory it can consume.
You don't have to worry about this since
all the assignments for this class are
designed to fit within the memory
constraints.
Here, I'm going to show the results of
running your commands and the results from
the tu, tutorial.
As you can see, both of them match.
Here is for the output from evaluating
eval cout a and b and here's the
accompanying output as well.
You can verify this on your own as you try
out the two.
Now consider what happens if I
accidentally enter something wrongly.
So for instance, on line five here,
instead of the variable cin, I'm going to
put cind.
Now I go back to the Programming
Assignments page, and I submit that file.
(Clicking) Sometimes the results are not
immediately available, and you will see
here that you have nothing here.
Just wait patiently and refresh the page.
Here you go.
We have the same output as before except
now on this particular line KBDD informs
us that it's not able to find the variable
of cind.
As you can see KBDDs quite robust to the
inputs that you can give it.
However, in the event that the two
actually does crash from some command you
give it, you'll be able to see the KBDD
standard error.
You can report this to us and we can
investigate what happened, and there you
have it.
A very short introduction of how you can
use the KBDD tool, through the class
website.
Please let us know if you have any
questions through the discussion forms on
our class website.
Thank you.