The second time that I followed you

Gah, I don't want to read about KITT today, I want to do the exercises from Mathematics in Civilization by H. L. Resnikoff and R. O. Wells. I've had this book lying on my shelf untouched for over four years, and last night I happened to pick it up and read a short section about real numbers, and suddenly I'm burning to spend more time with it.

Still frames in your mind

Actually, I do kinda want to read about FPS today. But I also want to download all the old photos which are still on my camera, sort out which ones need to be preserved as replacements for the ones which got corrupted on my old hard drive, and then delete the rest. It'll be a half-day's work.

He's right, but I lose my will

I don't want to read about real business cycle theory today, I want to learn Sage.

No, really. Any material on RBC theory includes a mention of the Hodrick-Prescott filter, and every time I see that I'm seized by a wild desire to implement it myself, because it looks so invitingly simple:

\[ \min_{y_{t}^{g}} \; \sum_{t=1}^{\infty} \left[ \left( y_t - y_{t}^{g} \right)^2 + \lambda \left[ \left( y_{t+1}^{g}-y_{t}^{g} \right) - \left( y_{t}^{g} - y_{t-1}^{g} \right) \right]^2 \right] \]

Where $y_t$ is the data point of series $y$ at time $t$, and $y_{t}^{g}$ is the data point of the trend series $y^g$ at time $t$ (the output of the filter). The above optimisation penalises for volatility in the estimated trend as well as deviations from the actual data. $\lambda$ is just a weighting parameter.

Anyway, I'm just burning to code this up in GAUSS (I'd have to do the calculus by hand, but GAUSS would love the minimisation part). However, soon my academic career will be over and I will no longer be able to rely on university licenses for analytical engines. For hobby projects, it's best if I start relying on something open, like Sage; the HP filter seems like a good experimental project for learning with when I switch to my new open engine. But I want to do it now.

The work for somebody else's dream

Oh man, I particularly don't want to read about rational expectations today.

I want to go have a picnic somewhere. Then get ice cream from Kaffee Eis and wander along the waterfront with it. Then cook something exquisite and time-consuming for dinner.

That's okay, my will is good

I don't want to read about investment theory today, I want to walk the Skyline Walkway.

Good day to be alive, he said

I don't want to read about unit roots today, I want to make Vienna bread.

Tell me again, I forgot

After this is over, I'm going to Good as Gold on Victoria Street to see if Keeps look as good in person. Online, I like The Dorian and The Duke.