+<<load_libraries,results="hide",message=FALSE,warning=FALSE,echo=FALSE>>=
+require("lattice")
+require("grid")
+require("Hmisc")
+require("gridBase")
+opts_chunk$set(dev="cairo_pdf",
+ out.width="0.8\\textwidth",
+ out.height="0.8\\textheight",
+ out.extra="keepaspectratio")
+opts_chunk$set(cache=TRUE, autodep=TRUE)
+options(device = function(file, width = 6, height = 6, ...) {
+ cairo_pdf(tempfile(), width = width, height = height, ...)
+ })