Publications by Isomorphismes
I’ve peeped a number of object-oriented R tutorials. This…
I’ve peeped a number of object-oriented R tutorials. This is the first one I could make it through. Easy and pleasant to read. Related To leave a comment for the author, please follow the link and comment on their blog: isomorphismes. R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topic...
522 sym
What’s the difference between POSIXct and POSIXlt?
POSIXct is the signed number of seconds since “the epoch”. For example it was 1351298112 UTC (GMT) when I wrote this. (1351298112 UTC = Sat Oct 27, 2:35 am GMT = Fri Oct 26, 8:35 pm EST = Fri Oct 26, 5:35 pm PST = 2:35 pm HST) POSIXlt is one of many text | character | string formats such as: May 17, 2017 17/5/2017 17-5-17 05:24:39 Relate...
729 sym
nice ggplot intro tutorial. Just run the commands, about 6 pages…
nice ggplot intro tutorial. Just run the commands, about 6 pages = flexible 1-3 hours of learning, depending how much reading you want to pair it with by Ramon Saccilotto Related To leave a comment for the author, please follow the link and comment on their blog: isomorphismes. R-bloggers.com offers daily e-mail updates about R news and tutor...
566 sym
Tibshirani’s original paper on the lasso. Breiman’s…
Tibshirani’s original paper on the lasso. Breiman’s Garotte — 1993 Tibshirani lasso paper submitted — 1994 Tibshirani lasso paper revised — 1995 Tibshirani lasso paper accepted — 1996 This is one of those papers that I’m so excited about, I feel like “You should just read the whole thing! It’s all good!” But I realise that’s...
3631 sym R (3 sym/3 pcs) 32 img
Regressions 101: “Significance”
SETUP (CAN BE SKIPPED) We start with data (how was it collected?) and the hope that we can compare them. We also start with a question which is of the form: how much tax increase is associated with how much tax avoidance/tax evasion/country fleeing by the top 1%? how much traffic does our website lose (gain) if we slow down (speed up) the load ti...
8243 sym R (2 sym/2 pcs) 22 img
±∞
The Cauchy distribution (?dcauchy in R) nails a flashlight over the number line and swings it at a constant speed from 9 o’clock down to 6 o’clock over to 3 o’clock. (Or the other direction, from 3→6→9.) Then counts how much light shone on each number. In other words we want to map evenly from the circle (minus the top point) onto ...
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Subtraction Is Crazy
I was re-reading Michael Murray’s explanation of cointegration: and marvelling at the calculus. Calculus blows my mind sometimes. Like, hey guess how much we can do with subtraction. — protëa(@isomorphisms) March 28, 2013 Of course it’s not any subtraction. It’s subtracting a function from a shifted version of itself. Still doesn’...
1897 sym R (75 sym/1 pcs) 10 img
Whilst reading John Hempton’s post on shorting $HLF I…
only the most active trading days $HLF (HerbaLife weight-loss supplements / MLM) $HLF regular history big loss days and big volume days for $HLF. “Ackman” should instead read “Einhorn”. Whilst reading John Hempton’s post on shorting $HLF I decided to follow along in quantmod. Bronte Capital: It was the night before Christmas… fals...
4212 sym R (261 sym/2 pcs) 24 img
“I like this concept of “low volatility, interrupted by occasional periods of high volatility”. I…”
“I like this concept of “low volatility, interrupted by occasional periods of high volatility”. I think I will call it “volatility”.” – Daniel Davies via nonergodic (PS: If you didn’t see it before: try plotting this in R: vol.of.vol <- function(x) { dpois(x, lambda=dpois(x, 5) } … and so on, to your heart...
684 sym R (67 sym/2 pcs) 6 img
playing along with Elias Wegert in R: X <-…
sine mis-calculated the angles on sine mid-res, small cex, pch=46, sine low-res, small cex, pch=46 z^17th power sine in HCL rather than HSV cosh z+zz+zzz+zzzz+zzzzz+zzzzzz+zzzzzzz+zzzzzzzz+zzzzzzzzz+zzzzzzzzzz playing along with Elias Wegert in R: X <- matrix(1:100,100,100) #grid X <- X * complex(imaginary=.05) + t(X)/2...
775 sym R (624 sym/2 pcs) 20 img