How to output \wedge in R? - r

How can I output the wedge symbol in R?
For example if I wanted C ∧ W, I might use $𝐶 \wedge 𝑊$ in LaTeX. This is helpful when I have to use R to write a factor structure diagram.

The wedge operator is apparently not included in the R ?plotmath functionality. You can do this with a Unicode symbol, although it could conceivably be sensitive to the fonts available on your system/for a particular output format. (To figure out the appropriate code I did a web search for "Unicode wedge" and found e.g. the wikipedia page; see also here)
png("wedge.png")
plot(0:1,0:1, type="n", ann=FALSE,axes=FALSE)
text(0.5, 0.5, "A \u2227 B", cex=5)
dev.off()
If you want to go for the full-blown LaTeX solution you can use the tikzDevice package:
library(tikzDevice)
tikz("wedge.tex", standAlone = TRUE)
plot(0:1,0:1, type="n", ann=FALSE,axes=FALSE)
text(0.5, 0.5, "$A \\wedge B$", cex=5)
dev.off()
system("pdflatex wedge; pdfcrop wedge.pdf; convert wedge-crop.pdf wedge2.png")

Related

Expression in R

I want to use expression for my ylab= when plotting in R. How do I get characters, using expression using the \mathcal{} style font? I am running Ubuntu and I don't want to use ggplot.
To clarify: part of the ylab will contain mathcal characters and part of it will not (and will be a formula). That's why I want to use expression
It is this symbol which I want:
= \mathcal{E}
One possible solution is to use tikz, which is kind of awesome, here is a much less beautiful example than the one they generate in the help of function tikzDevide::tikz:
require(filehash)
require(tikzDevice)
tikz("sinhplot.tex", width = 8, height = 4,
standAlone = TRUE,
packages = c("\\usepackage{tikz}",
"\\usepackage[active,tightpage,psfixbb]{preview}",
"\\PreviewEnvironment{pgfpicture}",
"\\setlength\\PreviewBorder{0pt}",
"\\usepackage{amssymb}")
plot(sinh, col="steelblue", lwd=2, xlim=c(-3,3), xlab="$\\mathcal E= [-3 , 3]$")
grid()
dev.off()
tools::texi2dvi(sinhplot,pdf=T)
system(paste(getOption('pdfviewer'),'sinhplot.pdf'))
The result looks quite nice!
Another solution is to just give up having beautiful characters in the labels of your figures...

R barplot with German encoding

My R script uses the R visialization library barplot. The problem is, that I need German characters such as äöü in the labeling.
I am working with the Eclipse plugiin StatET and on a 64-bit-Windows system. I tried to set up the correct encoding by Sys.setlocale(category="LC_ALL", locale="German_Germany");
Tests with print("äöü") gives the correct result, but when integrating those "Umlauts" in the barplot, it the graph shows the labeling with characters such as ä.
plot <- barplot(as.matrix(comp), beside=TRUE, ylim = c(0,100), main="äöü", legend.text = TRUE);
Any idea how to solve the problem?
EDIT
The result for Sys.getlocale('LC_CTYPE') is:
[1] "German_Germany.1252"
I can see the letters properly without alteration. Maybe try:
plot <- barplot(df, main= enc2utf8("äöü"), legend.text = TRUE);
As proposed here.
I do not know about Eclipse or 64-bit Windows, but since the question in the OP is phrased more generally: As far as I understand it, at least for exporting a plot as pdf, it is generally sufficient to set the correct locale (as you have) and putting the characters in octal representation (\344\366\374). E.g,
Sys.setlocale("LC_CTYPE", "german")
plot <- barplot(as.matrix(comp), beside=TRUE, ylim = c(0,100), main="\344\366\374\337", legend.text = TRUE)

Saving plots with "≤" and "≥" symbols in R

I have a strange problem:
I am working on a plot that in a legend text contains "≥" symbol. For example, "x ≥ 2". Interestingly, the symbol appears correctly when I plot it using the R graphic device, but it appears incorrectly when I save it as PDF or EPS.
Any suggestions how can I save it in PDF / EPS correctly?
Are you adding the symbol using an expression and the relevant ?plotmath markup? I suspect the problem is that you've literally used the "≥" glyph in the legend text. That will only work if you set the encoding correctly (see ?pdf), and then that may not work well everywhere.
Doing this va plotmath should be portable:
plot(1:10)
legend("topleft",
legend = c(expression(x >= 2), expression(x <= 1)),
pch = 1:2)
I suspect you're using a mac?
Use cairo_pdf instead of pdf:
> cairo_pdf("tmp.pdf")
> plot(2:10, xlab="x ≥ 2")
> dev.off()
null device
1

How can I use latex code in R plot? [duplicate]

I would like to add LaTeX typesetting to elements of plots in R (e.g: the title, axis labels, annotations, etc.) using either the combination of base/lattice or with ggplot2.
Questions:
Is there a way to get LaTeX into plots using these packages, and if so, how is it done?
If not, are there additional packages needed to accomplish this.
For example, in Python matplotlib compiles LaTeX via the text.usetex packages as discussed here: http://www.scipy.org/Cookbook/Matplotlib/UsingTex
Is there a similar process by which such plots can be generated in R?
The CRAN package latex2exp contains a TeX function that translate LaTeX formulas to R's plotmath expressions. You can use it anywhere you could enter mathematical annotations, such as axis labels, legend labels, and general text.
For example:
x <- seq(0, 4, length.out=100)
alpha <- 1:5
plot(x, xlim=c(0, 4), ylim=c(0, 10),
xlab='x', ylab=TeX(r'($\alpha x^\alpha$, where $\alpha \in \{1 \ldots 5\}$)'),
type='n', main=TeX(r'(Using $\LaTeX$ for plotting in base graphics!)', bold=TRUE))
for (a in alpha) {
lines(x, a*x^a, col=a)
}
legend('topleft',
legend=TeX(sprintf(r'($\alpha = %d$)', alpha)),
lwd=1,
col=alpha)
produces this plot.
Here's an example using ggplot2:
q <- qplot(cty, hwy, data = mpg, colour = displ)
q + xlab(expression(beta +frac(miles, gallon)))
As stolen from here, the following command correctly uses LaTeX to draw the title:
plot(1, main=expression(beta[1]))
See ?plotmath for more details.
You can generate tikz code from R:
http://r-forge.r-project.org/projects/tikzdevice/
Here's something from my own Lab Reports.
tickzDevice exports tikz images for LaTeX
Note, that in certain cases "\\" becomes "\" and "$" becomes "$\" as in the following R code: "$z\\frac{a}{b}$" -> "$\z\frac{a}{b}$\"
Also xtable exports tables to latex code
The code:
library(reshape2)
library(plyr)
library(ggplot2)
library(systemfit)
library(xtable)
require(graphics)
require(tikzDevice)
setwd("~/DataFolder/")
Lab5p9 <- read.csv (file="~/DataFolder/Lab5part9.csv", comment.char="#")
AR <- subset(Lab5p9,Region == "Forward.Active")
# make sure the data names aren't already in latex format, it interferes with the ggplot ~ # tikzDecice combo
colnames(AR) <- c("$V_{BB}[V]$", "$V_{RB}[V]$" , "$V_{RC}[V]$" , "$I_B[\\mu A]$" , "IC" , "$V_{BE}[V]$" , "$V_{CE}[V]$" , "beta" , "$I_E[mA]$")
# make sure the working directory is where you want your tikz file to go
setwd("~/TexImageFolder/")
# export plot as a .tex file in the tikz format
tikz('betaplot.tex', width = 6,height = 3.5,pointsize = 12) #define plot name size and font size
#define plot margin widths
par(mar=c(3,5,3,5)) # The syntax is mar=c(bottom, left, top, right).
ggplot(AR, aes(x=IC, y=beta)) + # define data set
geom_point(colour="#000000",size=1.5) + # use points
geom_smooth(method=loess,span=2) + # use smooth
theme_bw() + # no grey background
xlab("$I_C[mA]$") + # x axis label in latex format
ylab ("$\\beta$") + # y axis label in latex format
theme(axis.title.y=element_text(angle=0)) + # rotate y axis label
theme(axis.title.x=element_text(vjust=-0.5)) + # adjust x axis label down
theme(axis.title.y=element_text(hjust=-0.5)) + # adjust y axis lable left
theme(panel.grid.major=element_line(colour="grey80", size=0.5)) +# major grid color
theme(panel.grid.minor=element_line(colour="grey95", size=0.4)) +# minor grid color
scale_x_continuous(minor_breaks=seq(0,9.5,by=0.5)) +# adjust x minor grid spacing
scale_y_continuous(minor_breaks=seq(170,185,by=0.5)) + # adjust y minor grid spacing
theme(panel.border=element_rect(colour="black",size=.75))# border color and size
dev.off() # export file and exit tikzDevice function
Here's a cool function that lets you use the plotmath functionality, but with the expressions stored as objects of the character mode. This lets you manipulate them programmatically using paste or regular expression functions. I don't use ggplot, but it should work there as well:
express <- function(char.expressions){
return(parse(text=paste(char.expressions,collapse=";")))
}
par(mar=c(6,6,1,1))
plot(0,0,xlim=sym(),ylim=sym(),xaxt="n",yaxt="n",mgp=c(4,0.2,0),
xlab="axis(1,(-9:9)/10,tick.labels,las=2,cex.axis=0.8)",
ylab="axis(2,(-9:9)/10,express(tick.labels),las=1,cex.axis=0.8)")
tick.labels <- paste("x >=",(-9:9)/10)
# this is what you get if you just use tick.labels the regular way:
axis(1,(-9:9)/10,tick.labels,las=2,cex.axis=0.8)
# but if you express() them... voila!
axis(2,(-9:9)/10,express(tick.labels),las=1,cex.axis=0.8)
I did this a few years ago by outputting to a .fig format instead of directly to a .pdf; you write the titles including the latex code and use fig2ps or fig2pdf to create the final graphic file. The setup I had to do this broke with R 2.5; if I had to do it again I'd look into tikz instead, but am including this here anyway as another potential option.
My notes on how I did it using Sweave are here: http://www.stat.umn.edu/~arendahl/computing
I just have a workaround. One may first generate an eps file, then convert it back to pgf using the tool eps2pgf. See http://www.texample.net/tikz/examples/eps2pgf/
h <- rnorm(mean = 5, sd = 1, n = 1000)
hist(h, main = expression(paste("Sampled values, ", mu, "=5, ", sigma,
"=1")))
Taken from a very help article here https://stats.idre.ucla.edu/r/codefragments/greek_letters/
You can use the following, for example:
title(sub=TeX(sprintf(paste("Some latex symbols are ", r'(\lambda)', "and", r'(\alpha)'))))
Just remember to enclose LaTeX expressions in paste() using r'()'
You can also add named objects in the paste() function. E.g.,
lambda_variable <- 3
title(sub=TeX(sprintf(paste(r'(\lambda=)', lambda_variable))))
Not sure if there are better ways to do this, but the above worked for me :)

how to show $\{ X_t \}$ in the title of a plot of R

How to show $\{ X_t \}$ of Latex in the title of a plot of R?
For example
plot(slot(x,"GRID"),slot(x,"PATH"),type="l", xlab="Time t",ylab="X",
main=paste("Simulation of \{X_t\}"))
Thanks!
Assuming you will provide meaningful arguments for the slot expressions, then I think there is a reasonable chance that this is what you want:
plot(1:10,1:10,type="l", xlab="Time t",ylab="X",
main=expression("Simulation of {"*X[t]*"}"))
This is a plotmath expression that presents "t" as a subscript of "X" and that expression is enclosed in curley braces. If I have misread your request, then note that the "*" character is a separator in the plotmath syntax and the braces are simply characters than can be deleted. (The LaTeX expressions don't make a lot of sense to those of us who just use the plotmath syntax, so describing what you want in prose or mathematical jargon would work better for any clarifications.)
To have R emulate LaTeX typesetting, see the examples and methods described in ?plotmath.
To actually have LaTeX typeset your plot text, use the tikz() graphics device provided by the tikzDevice package.
The group() plotmath function can be used to formalise DWin's answer. This solution has the advantage (IMHO) of not using strings as part of the expression. Instead we use the ~ operator to add spacing (whitespace is ignored).
plot(1:10, 1:10, type = "l", xlab = "Time t", ylab = "X",
main=expression(Simulation ~ of ~ group("{", X[t], "}")))
The bgroup() plotmath function provides scalable delimiters but is used in the same manner as the example code above.
Edit (In response to ran2's comment):
The same approaches can be used in ggplot and lattice, using the power of plotmath, just as with base graphics. E.g.
require(ggplot2)
df <- data.frame(A = 1:10, B = 1:10)
qplot(A, B, data = df,
main = expression(Simulation ~ of ~ group("{", X[t], "}")))

Resources