[Axiom-developer] Intrinsic Error Rate

[daly]

I have been asked to do a video for the Clojure programming 
group about literate programming and this was a recent reply 
explaining the idea. I don't think I've mentioned this special
property of literate programming before but I think it is one
key reason to develop the practice. 

Tim

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> > Personally if you have done or would be interested in doing a quick
> > vid cast of how you progress through your workflow, I think that
would
> > be very interesting.
> 
> Sort of "extreme pair programming with everybody"? :-)
> There is no such thing as a simple job but I'll see what I can do.
> A watchable video takes time to compose.

I am composing the notes for this video and I realized I have
a piece of programming information about myself that you probably
do not have about yourself.

Years ago I wrote a program (Archive) to allow users of a time
shared mainframe to back up programs to magnetic tape. This was
a single person project. As an experiment I copied every input
at the keyboard and every output of every command. I also kept
a journal of everything I did, why I did it, and what failed.

The key result was that I discovered what I call my personal
"irreducible error rate". If I do 100 things I will make 3 errors.
This was independent of the task. So typing 100 characters has
3 wrong letters which were mostly caught while typing. Writing
100 lines of code had 3 errors somewhere. Composing email
introduces 3 errors per 100 lines of code.

Most of the errors were trivial (spelling), some were syntax
(missing delimiter), some were semantic (wrong action), some
were design (wrong solution). 

As a result of this measurement I have formed habits to look
for the 3 mistakes I know exist. For example, I am writing a
book of Axiom graphics images (a "gallery"). I have written
679 equations so far, which are going to create the images.

I know there are at least 21 uncaught errors lurking in those
equations. So before I attempt to generate the images I will
examine them in detail with an eye toward finding what I know
is there.

Literate programming is both a source of errors and a help.

It is a source of errors because I have more typing to do
and will generate bad latex and meaningless sentences, as 
well as the "standard" coding errors. So in some sense I have
added to the number of errors I WILL introduce. But the tools,
like the compiler, tex and spellcheck will at least warn me of
these failures.

However, literate programming helps because I am explaining
what I am doing to myself as well as others. This really 
reduces the "big", "costly" errors, those in the design and
implementation. There are no tools to help so I have to create
a discipline that will highlight these errors as soon as
possible.

I KNOW my intrinsic error rate. What is yours? 

What discipline can you apply to your work to find your errors?

I'm not sure how to get this important piece of self-knowledge
into the video so I thought I'm mention it here.

Tim Daly