Tuesday, September 28, 2010

Why Professional Certification Might Be Good

Sometimes I think we need professional certification in this industry. I supported the ICCP for a long time.

In addition to certification, which requires ongoing educational credits to maintain, there ought to be a process for revoking one's certification, requiring them to pass their exams again.

Here's three strikes against two clods who wasted hours on -- perhaps -- the dumbest things possible.

Strike 1. Counting From Zero
I then ponited out that the Microsoft doco is weird because the highest
number allowed by ulong is 18,446,744,073,709,551,615 which ends in an odds
number

I remineded him that 2**64 = 18,446,744,073,709,551,616
Apparently, this was the first time anyone realized how counting from zero works. If they had actually thought about this, they could have tried a smaller example. For example three bits. 2**3 = 8. When you enumerate the values you get 0, 1, 2, 3, 4, 5, 6, 7. The highest value is 2**3-1. It's not "weird". It's a trivially obvious mathematical fact.

It works like this: n values have numbers from 0 to n-1. Didn't know that? Consider your certification revoked. Even hobbyists know this.

Strike 2. Wrong Tools and Wrong Approach

This is more subtle and involves two strikes. We'll look at just one of them.
Then he wanted a spreadsheet of 2 raised to nth power.

I put it together and the numbers just looked weird. I then realized that
when you type a number that contains more than 15 digits in a cell,
Microsoft Excel changes any digits past the fifteenth place to zeroes

What I felt like saying is that Python has built in this concept of "long
integers" which has unlimited precision and it automatically switches to
them
One of the clods knew Python. Instead of writing a trivial loop in Python, apparently, clod #1 proceeded to type numbers into a spreadsheet. The clod didn't compute them -- with formulas or software -- the clod typed the numbers. Typed. Have Python. Elected to type. How did they do the calculations? On a pocket calculator? Oh the shame.

Also, additional penalties for exhaustive enumeration. They sent me the spreadsheet as if it was somehow important that they could enumerate values between 2**0 and 2**135. No summary or rule. Just a mountain of useless numbers.

Strike 3. Floating Point

This is not news. Nor should it be. Indeed, this should be the first set of questions on the certification exam. If you can't figure out floating point, you can't write software. Period. Please find another job in an industry where you won't waste time on this.

Floating point is not simple, and everyone should study it before they are allowed to charge money for creating software. Running random experiments and exhaustively enumerating values is not studying. That's not even hobbyist stuff. Try actually reading. Starting with the standard. And David Goldberg's "What Every Computer Scientist Should Know About Floating-Point Arithmetic".
contains more than 15 digits in a cell,
Microsoft Excel changes any digits past the fifteenth place to zeroes
This is not "news". The link provided in the email ("Last digits are changed to zeroes when you type long numbers in cells of Excel") indicates a profound lack of understanding.

They could not have noticed that this is near 2**50. They never looked up the IEEE floating point representation that -- pretty clearly -- says that there are only 52 bits of useful information. Wikipedia reminds us that this is about 15 decimal digits. Rather than look this up, they chose to be astonished.

These clods were astonished that floating-point numbers have a finite mantissa. Astonished that -- empirically -- they had stumbled on the fact that the mantissa is about 50 bits.

How much time did they waste on this? More importantly, how can they consider their activities to be "professional"? Unable to count from zero? Using the wrong tools and exhaustively enumerating the obvious? Not realizing the floating-point values have limited precision?

I find it appalling. Their escapades sound like two home hobbyists with their fist ever copy of C#. Not like professionals.