R - explore the graphs stocked in a variable - r

Question

I there a way to see in R how a graph was built into a variable: the code behind the graph. I have tried the str(), deparse(), and replayPlot() functions but these don't give the answer I am searching for.
Precisely I am looking at the result returned by the MackChainLadder() function from the "ChainLadder" package. When I plot the the variable, say plot(MCL), it returns me 6 different graphs. Is it a way to find out how these graphs were built and saved into the variable?
library("ChainLadder")
MCL <- MackChainLadder(ABC)
plot(MCL)

Answer 1

One way to do this is to look at the package source code directly (download it from this page):
http://cran.r-project.org/web/packages/ChainLadder/index.html
The trick is finding the right method that plot() calls. I think it might be this one in MackChainLadderFunctions.R
################################################################################
## plot
##
plot.MackChainLadder <- function(x, mfrow=c(3,2), title=NULL,lattice=FALSE,...){
.myResult <- summary(x)$ByOrigin
.FullTriangle <- x[["FullTriangle"]]
.Triangle <- x[["Triangle"]]
if(!lattice){
if(is.null(title)) myoma <- c(0,0,0,0) else myoma <- c(0,0,2,0)
op=par(mfrow=mfrow, oma=myoma, mar=c(4.5,4.5,2,2))
plotdata <- t(as.matrix(.myResult[,c("Latest","IBNR")]))
n <- ncol(plotdata)
if(getRversion() < "2.9.0") { ## work around missing feature
bp <- barplot(plotdata,
legend.text=c("Latest","Forecast"),
## args.legend=list(x="topleft"), only avilable from R version >= 2.9.0
names.arg=rownames(.myResult),
main="Mack Chain Ladder Results",
xlab="Origin period",
ylab="Amount",#paste(Currency,myUnit),
ylim=c(0, max(apply(.myResult[c("Ultimate", "Mack.S.E")],1,sum),na.rm=TRUE)))
}else{
bp <- barplot(plotdata,
legend.text=c("Latest","Forecast"),
args.legend=list(x="topleft"),
names.arg=rownames(.myResult),
main="Mack Chain Ladder Results",
xlab="Origin period",
ylab="Amount",#paste(Currency,myUnit),
ylim=c(0, max(apply(.myResult[c("Ultimate", "Mack.S.E")],1,sum),na.rm=TRUE)))
}
## add error ticks
## require("Hmisc")
errbar(x=bp, y=.myResult$Ultimate,
yplus=(.myResult$Ultimate + .myResult$Mack.S.E),
yminus=(.myResult$Ultimate - .myResult$Mack.S.E),
cap=0.05,
add=TRUE)
matplot(t(.FullTriangle), type="l",
main="Chain ladder developments by origin period",
xlab="Development period", ylab="Amount", #paste(Currency, myUnit)
)
matplot(t(.Triangle), add=TRUE)
Residuals=residuals(x)
plot(standard.residuals ~ fitted.value, data=Residuals,
ylab="Standardised residuals", xlab="Fitted")
lines(lowess(Residuals$fitted.value, Residuals$standard.residuals), col="red")
abline(h=0, col="grey")
plot(standard.residuals ~ origin.period, data=Residuals,
ylab="Standardised residuals", xlab="Origin period")
lines(lowess(Residuals$origin.period, Residuals$standard.residuals), col="red")
abline(h=0, col="grey")
plot(standard.residuals ~ cal.period, data=Residuals,
ylab="Standardised residuals", xlab="Calendar period")
lines(lowess(Residuals$cal.period, Residuals$standard.residuals), col="red")
abline(h=0, col="grey")
plot(standard.residuals ~ dev.period, data=Residuals,
ylab="Standardised residuals", xlab="Development period")
lines(lowess(Residuals$dev.period, Residuals$standard.residuals), col="red")
abline(h=0, col="grey")
title( title , outer=TRUE)
par(op)
}else{
## require(grid)
## Set legend
fl <-
grid.layout(nrow = 2, ncol = 4,
heights = unit(rep(1, 2), "lines"),
widths =
unit(c(2, 1, 2, 1),
c("cm", "strwidth", "cm",
"strwidth"),
data = list(NULL, "Chain ladder dev.", NULL,
"Mack's S.E.")))
foo <- frameGrob(layout = fl)
foo <- placeGrob(foo,
linesGrob(c(0.2, 0.8), c(.5, .5),
gp = gpar(col=1, lty=1)),
row = 1, col = 1)
foo <- placeGrob(foo,
linesGrob(c(0.2, 0.8), c(.5, .5),
gp = gpar(col=1, lty=3)),
row = 1, col = 3)
foo <- placeGrob(foo,
textGrob(label = "Chain ladder dev."),
row = 1, col = 2)
foo <- placeGrob(foo,
textGrob(label = "Mack's S.E."),
row = 1, col = 4)
long <- expand.grid(origin=as.numeric(dimnames(.FullTriangle)$origin),
dev=as.numeric(dimnames(.FullTriangle)$dev))
long$value <- as.vector(.FullTriangle)
long$valuePlusMack.S.E <- long$value + as.vector(x$Mack.S.E)
long$valueMinusMack.S.E <- long$value - as.vector(x$Mack.S.E)
sublong <- long[!is.na(long$value),]
xyplot(valuePlusMack.S.E + valueMinusMack.S.E + value ~ dev |
factor(origin), data=sublong, t="l", lty=c(3,3,1), as.table=TRUE,
main="Chain ladder developments by origin period",
xlab="Development period",
ylab="Amount",col=1,
legend = list(top = list(fun = foo)),...)
}
}