🚀 go-pugleaf

In article <14476@oddjob.UChicago.EDU> matt@oddjob.UChicago.EDU (My Name Here) writes:
>Oliver Laumann quotes Butler W. Lampson:

>[...] A friend of mine had worked for a certain electronic
>instrument company doing numerical analysis for some engineers.  One
>engineer gave him a 200x200 matrix to invert.  (This was in the early
>70s when that was a big matrix.)  My friend did the job and noticed
>that the inverse looked a little familiar.  He asked the engineer,
>"Could this matrix represent a rotation of some sort?"  Answer: "Why,
>yes, you could consider it as one."  (The inverse was the transpose.)

I wonder if this is an example of a "software urban legend".  Forman Acton
mentions a very similar situation in his 1970 book on numerical analysis,
although there it is purported to be a first-person experience, and it
was claimed that 15 minutes of analysis were necessary to determine that
the matrix was orthogonal (thus representing a rotation).

Incidentally, this same book has some amusing flaming passages about
people who use too many cycles, and about the evils of recursion...

							stan shebs
							shebs@cs.utah.edu