cgrubb

Nominally about rock climbing, but really a study of the ego, why we invest so much effort in protecting it, and how little we get for that investment.

Comment · 9 years ago

The Thomas Watson quote (only a market for 5 computers) is a bit of an urban legend:

http://geekhistory.com/content/urban-legend-i-think-there-wo...

Comment · 9 years ago

I think this is a good youtube video for someone starting from zero:

https://www.youtube.com/watch?v=_DTpQ4Kk2wA

An issue is how to enter the symbols. The way I do it is I created some input methods for Mac and Windows which use at-signs followed by the APL community name for the symbol:

    @times       ×
    @grade       ⍋ 
    @reverse     ⌽
    @domino      ⌹

https://github.com/clarkgrubb/latex-input/tree/master/apl

Comment · 9 years ago

I upgraded from 2 to 3 last year. I'm liking it.

I've embraced type hints. Although they have no run-time effect, there is a command line tool called mypy which enforces correctness. It has caught more than a few errors for me. Declaring the types of arguments and return values is a help when reading the code imo.

Comment · 10 years ago

A light rail system over Sepulveda Pass would probably require drilling a tunnel. Early estimates are at least $6B: http://www.latimes.com/local/lanow/la-me-ln-sepulveda-pass-t.... It could get built, but I don't think the final price tag is going to put the lane expansion to shame.

Buses can already use the HOV lanes. One of the expansion lanes (the northbound one) was an HOV lane, so now there are HOV lanes in both directions. Who cares, given how few riders buses attract.

Comment · 10 years ago

There is precedent for charging $2 tolls in CA: https://en.wikipedia.org/wiki/California_State_Route_73

Comment · 10 years ago

    Vehicle capacity on the northbound 405 has increased from 10,000
    vehicles per hour to 11,700 vehicles per hour at peak times.

http://thesource.metro.net/2015/05/28/study-finds-traffic-on...

So capacity increased maybe 10k a day, or 750M over a 20 year period. Makes the $1B investment seem reasonable.

Comment · 10 years ago

Releasing all drug offenders (both federal and state) would reduce the US prison population 14%: http://fivethirtyeight.com/datalab/releasing-drug-offenders-...

Comment · 10 years ago

> Is that even statistically significant?

Not if your significance level is the customary 5%:

    > 1 - pbinom(2, 7, 1/7)
    [1] 0.06522914

The astronauts carried dosimeters, and all got rad doses below what some DOE employees get, so maybe there is better population for an observational study.