multiplot: Multiple plot function
In ivanliu1989/RQuant: A collection of generic functions

ggplot objects can be passed in ..., or to plotlist (as a list of ggplot objects) - cols: Number of columns in layout - layout: A matrix specifying the layout. If present, 'cols' is ignored.

1	multiplot(..., plotlist = NULL, file, cols = 1, layout = NULL)

If the layout is something like matrix(c(1,2,3,3), nrow=2, byrow=TRUE), then plot 1 will go in the upper left, 2 will go in the upper right, and 3 will go all the way across the bottom.

x <- 1:10
y1 <- 1:10
y2 <- 21:30

plt1 <- ggplot(data=data.frame(x=x, y=y1)) + geom_point(aes(x,y))
plt2 <- ggplot(data=data.frame(x=x, y=y1)) + geom_line(aes(x,y))
plt3 <- ggplot(data=data.frame(x=x, y=y1 + rnorm(10))) + geom_line(aes(x,y))

multiplot(plt1,plt2,plt3, cols = 2)