similar to: write() gotcha

Hi I thought I'd pass one of my package through R CMD check with R-2.4.0 with the following result (it's clean under R-2.3.1): [snip] > > # histogram of the fourth power: > hist(out^4, col="gray") *** caught bus error *** address 0x12, cause 'invalid alignment' Traceback: 1: sort(x, partial = c(half, half + 1)) 2: sum(sort(x, partial = c(half, half +

The following gotcha caught me off-guard just now. I have two matrices, a and b: a <- matrix(1,3,3) b <- matrix(1,1,1) (note that both "a" and "b" are matrices). I want them in a list: > B <- NULL > B[[1]] <- a > B[[2]] <- b > B [[1]] [,1] [,2] [,3] [1,] 1 1 1 [2,] 1 1 1 [3,] 1 1 1 [[2]] [,1] [1,] 1

Hello everyone I am finding complex numbers to be printed oddly in R-alpha. > 1e100+1e100i [1] 1e+100+1e+100i > 1e100 + 1e44i [1] 1e+100+100000000000000008821361405306422640701865984i > dput(1e100+1e44i) 1e+100+100000000000000008821361405306422640701865984i > [same thing at home on a linux box] The first line is what I would expect, the second and third lines aren't: I

Hi has anyone coded up domain colouring for visualizing complex analytic functions (such as elliptic functions)? [ the idea is to depict a complex function f(z) using a filled.contour() variant in which the hue is given by Arg(f(z)), and the saturation by Mod(f(z)). ] -- Robin Hankin Uncertainty Analyst Southampton Oceanography Centre European Way, Southampton SO14 3ZH, UK tel

Hi. I have a factor and I want to extract just those elements that appear exactly once. How to do this? Toy example follows. > a <- as.factor(c(rep("oak",5) ,rep("ash",1),rep("elm",1),rep ("beech",4))) > a [1] oak oak oak oak oak ash elm beech beech beech beech Levels: ash beech elm oak > table(a) a ash beech elm oak

Hi If string <- "xyz" f <- function(x){1 + sin(cos(x)) + exp(x^2)} How do I manipulate "string" and f() to give the string "1 + sin(cos(xyz)) + exp(xyz^2)" ? -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743

Hi. Is there a straightforward way to convert a character string containing comma-delimited numbers to a numeric vector? In my application, I use system(executable.string, intern=TRUE) which returns a string like "[0.E-38, 2.096751179214927596171268230, 3.678944959657480671183123052, 4.976528845643001020345216157, 6.072390165503099343887569007, 7.007958550337542210168866070,

Hi The following gotcha took me a long time to catch: f <- function(x, main0="red", ...){ par(col.axis=main0) plot(x,...) } f(1:10,main="title here") f(1:10,main="title here",main0="blue") I can't quite succinctly summarize why the second case works but the first one doesn't. -- Robin Hankin Uncertainty Analyst National

Hi ?lines says For 'type = "h"', 'col' can be a vector and will be recycled as needed. Why doesn't lines() recycle colours for other types? If I type > plot(0:1,0:1,type="n") > lines(runif(11),runif(11),col=c("red","green")) > then all ten lines are red, with no warning given. Is there a reason why

Hi In Sweave, how does one change the size of the plots? I tried using a hook: <<echo=FALSE, print=FALSE, fig=TRUE>>= options(SweaveHooks=list(fig=function() ps.options(width=1))) library(graphics) pairs(iris) @ but this didn't change the size of the figure. How to make the figures a different size? -- Robin Hankin Uncertainty Analyst National Oceanography Centre,

Hi how do I extract those components of a list that satisfy a certain requirement? If jj <- list(list(a=1,b=4:7),list(a=5,b=3:6),list(a=10,b=4:5)) I want just the components of jj that have b[1] ==4 which in this case would be the first and third of jj, viz list (jj[[1]],jj[[3]]). How to do this efficiently? My only idea was to loop through jj, and set unwanted components to NULL,

Hi How do I specify an S4 class with a slot that is potentially numeric, but NA by default? I want the slot to be NA until I calculate its value (an expensive operation, not needed for all applications). When its value is known, I will create a new object with the correct value inserted in the slot. I want "NA" to signify "not known". My attempt fails because

Hi I'm developing an R package that needs to execute some code written in pari/gp. I've used this before from an R package (elliptic) but the interface is very basic: the R function creates a string such as the following: string <- echo ' ellwp ([ 2+0*I , 0+2*I ], 1+0*I )' | gp -q And then system(string) returns the output from gp which then needs to be text processed

Hi How do I generate all ways of ordering sets of indistinguishable items? suppose I have two A's, two B's and a C. Then I want AABBC AABCB AACBC ABABC . . .snip... BBAAC . . .snip... CBBAA [there are 5!/(2!*2!) = 30 arrangements. Note AABBC != BBAAC] How do I do this? -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14

Hi I have a little vector function that takes a vector A of strictly positive integers and outputs a matrix M each of whose columns is the vector, modified in a complicated combinatorical way. Now I want to generalize the function so that A can include zeroes. Given A, I want to strip out the zeroes, pass it to my function, and pad M with rows at positions corresponding to the zeroes

Hi How do I make do.call() take "+" as a function for a list of more than two elements? Toy problem follows: f <- function(i){matrix((1:6)^i,2,3)} # Thus f() returns a matrix of size 2x3; I want to add a whole bunch of such matrices, # as in f(1) + f(2) + f(3) + f(4) # But: > do.call("+",sapply(1:4,f,simplify=FALSE)) Error in do.call("+",

Hi I have two datasets, A and B, consisting of two columns of numbers representing x and y coordinates. They have 10 and 6 rows respectively. I want to plot two scattergraphs, one above the other. The lower graph to contain A (10 points) and the upper graph to contain B (six points). The x-axes of the two graphs must line up. I then want to draw straight lines that connect points of B to a

Hi How do I get the output from table() in matrix form? If I have R> table(c(1,1,1,1,2,20)) 1 2 20 4 1 1 I want [,1] [,2] [,3] [1,] 1 2 20 [2,] 4 1 1 The problem is that names(table) is a vector of characters and I need the numeric values. I am using R> rbind(as.integer(names(x)),x) I thought tabulate() might be better as it takes an

Hi I want to write a little function that takes a vector of arbitrary length "n" and returns a matrix of size n+1 by n+1. I can't easily describe it, but the following function that works for n=3 should convey what I'm trying to do: f <- function(x){ matrix(c( 1 , 0 , 0 , 0, x[1] , 1 , 0 , 0, x[1]*x[2] , x[2] , 1 , 0,

Hi. I'm having difficulty following the advice given in help(Recall). Consider the two following toy functions: f1 <- function(n){ if(length(n)>1){return(sapply(n,f1))} matrix(n,n,n) } f2 <- function(n){ if(length(n)>1){return(sapply(n,Recall))} matrix(n,n,n) } f1() works as desired (that is, f(1:3), say, gives me a three element list whose i-th element is an