Sunday Music: Chicago Transit Authority

Album Title: Chicago Transit Authority

Why I Bought It: allyra again.

What I Like (Joyful): "Beginnings". Just a happy and hopeful song.

What Else I Like (Joyful): "Questions 67 and 68". Normally, I'd tack this on as an Honorable Mention, but I love love love this song, beginning to end, all the way to the triumphant call-out of the title at the end.

What I Sorta Like (Waitaminnit): "Does Anybody Really Know What Time It Is". The message is a good one, I guess, but I'd be tempted to belt anyone who answered me that way.

What I Don't Like (Ouch): "Liberation", a (to my ear) severely discordant instrumental - and the damn thing's fourteen-plus minutes long! Dishonorable Mention: "Free Form Guitar".

Overall: A mixed bag. What's good is outstanding - I'd add "Listen" and "I'm a Man" to the songs mentioned above - but there's a lot of it that ranges between opaque and painful. Still, that's what the "Remove from Playlist" menu item is for....

Timesaver

In my research on geodesics on prisms, I deal with things called "turn sequences", each of which may generate a geodesic. There are some simple necessary conditions I can use to weed out some sequences, but in general, the task has been a tedious one. I start with the turn sequence, and sketch out, by hand, a diagram. From this, I read off various coordinates, which I hand off to the computer. It then provides me with a list of quadratic inequalities, and I have to determine whether those inequalities are compatible. This has generally involved using Mathematica to graph each of them, or enough of them to show that they're incompatible. Long, boring, and vulnerable to mistakes.

I don't know why it took me so long, but I finally figured out how to automate the process. I now have a small suite of routines which allow me to feed in a turn sequence and get back a graphical representation of all of the inequalities, clearly showing whether they are compatible. As a bonus, I can use the resulting graph and another couple of routines to get an actual display of the corresponding geodesic (if the inequalities are compatible).

I'm rather pleased with myself. Unfortunately, there are so many other things going on that I won't have enough time to devote to *using* these tools for the next while. Ah, well....

Feet

I'm sitting here websurfing. Gracie is under the chair, and licking the sole of my left foot. I've been barefoot all day; Lord only knows what's attracting her attention.

(Switch feet. The right foot doesn't seem as interesting to her. Left/right again....)