Maybe I am glad that I had Professor Poonen for Math 55 – Discrete Math.

Because Professor Clancy wasn\’t here, Brian the TA took over for CS lecture and he talked about William Kahan, a UC Berkeley professor who taught Math 55 and is the godfather of floating point (he won a Turing Award–the highest achievement for computer science/mathematics–for floating point numbers in the 80s).

One student in his 1999 Math 55 class asked, \”Why do you grade so harshly?! With no partial credit?!\”

He simply answered, \”I\’ve got children and grandchildren. I don\’t want the computers and machinery they\’ll depend on in the future to compromise their safety in any way, just because they were programmed by computer scientists who had guessed without knowing if they were right. It\’s my own form of self-defense.\”

He\’s not talking about the computer games we play. He\’s talking about for example the rocket Ariane 5 which blew up right after its launch, because a computer scientist converted a floating point number (32 bits) to an int (16 bits).

Lesson: If you are a computer scientist, you better have a good lawyer.