Sticky post

Oh, and in my spare time, I invented TeX

Writing in Quanta, Susan D’Agostino has a fascinating interview with the computing-est of all computer scientists, Donald Knuth.  Who continues his Everest-like trek up his monumental Art of Computer Programming.  This (intrinsically) never-to-be-completed opus to the mathematics and techniques of algorithms was, for many of us, the first introduction to formal analysis of algorithms and Dr. Knuth.  But woven into the creation of ACP was the invention of TeX, the world’s most marvelous computer typesetting system. TeX was only supposed to be for my secretary and myself. Phyllis [Astrid Benson Winkler] was a wonderful secretary. She could read my handwriting … Continue reading Oh, and in my spare time, I invented TeX

KWIC, make me some hash!

IEEE Spectrum has a fascinating bio sketch of Hans Peter Luhn, inventor of the hashing and KWIC indexing algorithms. This is Luhn’s legacy: He helped show that computers and computation weren’t just the province of mathematics, statistics, and logic but also of language, linguistics, and literature. In his day, this was a revolutionary way to think about machines. Tip from the Geek Press. Continue reading KWIC, make me some hash!

R Tutorial: the non-linear equation solver

Need a numerical solution to simultaneous non-linear equations?  The nleqslv package is just what you’re looking for!  The coding required is minimal; just define the equations you want solved in a function, set some initial values, and let ‘er rip. Here’s an example that uses the method of moments to estimate the parameters of a beta-binomial distribution. Continue reading R Tutorial: the non-linear equation solver

Bump charts get renamed as SLOPEGRAPHS

Charlie Park has a nice post describing Tufte’s slopegraphs (old chart, new name). Kaiser Fung likes these a lot; he’s been calling them Bump charts. I introduce these to my undergrads when we discuss the paired t test. Tip from Update (16 July).  James Kierstead publishes an R implementation. Continue reading Bump charts get renamed as SLOPEGRAPHS

Better than pretty

Pretty R is a syntax formatter for R, it generates highlighted and properly indented R code suitable for including in an HTML document.  Better yet, all the R keywords are linked back to an online reference manual at!  Check it out. # multiple comparison with aov   s <- read.table(“dogFoodSales.txt”,header=T)   # fit the ANOVA model and perform post hoc test (Tukey’s HSD)   print( summary( smodel <- aov(sales ~ location, data=s) ) ) print( TukeyHSD(smodel,”location”, ordered=TRUE) )   # check residuals for normality   qqnorm(smodel$residuals) qqline(smodel$residuals) print(shapiro.test(smodel$residuals))   # check for homogeneity of variance   attach(s) print(bartlett.test(sales ~ … Continue reading Better than pretty