斜体希腊字母/乳胶样式数学在剧情标题 [英] Italic greek letters / latex-style math in plot titles

问题描述

我想在R.的绘图标题中创建乳胶样式的数学。 plotmath工具有一个有用但有限的表达式子集，它们可以显示，并使用非乳胶语法和样式。

I'd like to create latex-style math in plot titles in R. The plotmath tools have a useful but limited subset of expressions they can display, and use non-latex syntax and style.

例如，我打印等式$ \mathrm {d} \mathbf {x} = a [\theta - \mathbf {x }] \mathrm {d} t $在绘图的标题，并仍然评估某些变量的值。最好的解决方案是非常麻烦：

For instance, I would like to print the equation $\mathrm{d} \mathbf{x} = a [\theta - \mathbf{x}] \mathrm{d} t$ in the title of the plot, and still evaluate the value of certain variables. The best solution I have is the very cumbersome:

lambda <- 4
plot(1:10,1:10)

mtext(bquote(paste(d*bolditalic(x)[italic(t)] == alpha*(theta - bolditalic(x)[italic(t)] )*d*italic(t) +  .(lambda) * d * italic(B)[italic(t)] )), line=2.25,cex=2) 

或

require(ggplot2)
qplot(1:10, 1:10) + opts(title=bquote(paste(d*bolditalic(x)[italic(t)] == alpha*(theta - bolditalic(x)[italic(t)] )*d*italic(t) +  .(lambda) * d * italic(B)[italic(t)] )), line=2.25,cex=2)

这个问题几乎解决了这个问题，但我松了bquote显示变量数值的能力（在我的例子中为lambda）。有没有办法组合这些，所以我可以有斜体的希腊字母（变量的标准格式，例如由tex做）和评估在特定的值？

This question almost solves this, but I loose the ability of bquote to display the numerical value of a variable (lambda in my example). Is there a way to combine these so I can have italic greek letters (the standard format for variables, e.g. as done by tex) and evaluate at specific values?

有没有更好的方法，我可以简单的写tex语法的方程式，并将它们添加到我的图形？

Is there a much better way where I can simple write tex-syntax for equations and add them to my graphs?

推荐答案

您可以查看 tikzDevice 包装（或查看

You may want to check out the tikzDevice package (or take a look at its vignette first), which provides a natural way to write LaTeX math in R graphics.

我也有

这里是另一个例子：

library(tikzDevice)
library(ggplot2)
tikz('math.tex', standAlone = TRUE, width = 4, height = 4)
qplot(1:10, 1:10, 
  main = '$\\mathrm{d} \\mathbf{x} = a [\\theta - \\mathbf{x}] \\mathrm{d} t$')
dev.off()

如果运行 pdflatex math .tex ：

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