[R] splom, plotmath: how to add three lines of information with alignment?

[Marius Hofert]

Dear Baptiste,

thank you for your help. I tried to built in your suggestions into the splom. 
Below is the result. I decided to create the plotmath-expressions outside the 
function splom2, this will allow me later to horizontally shift (via phantom,
for example) the table entries so that they will be vertically aligned according 
to the "=" signs. Although an array is allowed to contain expressions, I could 
not manage to create it properly. Do you know a solution?

Cheers,

Marius

library(lattice) 
library(grid)
library(gridExtra)

## splom with customized lower.panel
## x: data
## expr.arr: array of expressions [(i,j,) entry contains expressions which are
##           plotted in a grid table in the lower panel (i,j)]
splom2 <- function(x, expr.arr){
    ## function for creating table 
    table.fun <- function(vec){ # single values for one panel
        grid.table(vec,
                   parse=TRUE, # parse labels as expressions
                   theme=theme.list(
                   gpar.corefill=gpar(fill=NA, col=NA), # make bg transparent
                   core.just="left") # justification of labels
                   ) 
    }
    ## splom
    splom(x, varname.cex=1.4,
          superpanel=function(z, ...){
              panel.pairs(z, upper.panel=panel.splom, lower.panel=function(i,j){
                  table.fun(expr.arr[i,j,])
              }, ...)
          })
}

## create data and array of expressions
d <- 4
x <- matrix(runif(d*1000), ncol=d)
expr.arr <- array(, dim=c(d,d,3), dimnames=c("i","j","val")) # d x d x 3 elements
for(i in 1:d){
    for(j in 1:d){
        # expr.arr[i,j,] <- expression(italic(a)==0, italic(bbb)==0, italic(c)==0) # does no work
	expr.arr[i,j,] <- c(bquote(italic(a)==.(0)), bquote(italic(bbb)==.(0)), bquote(italic(c)==.(0))) # same here
    }
}

## plot
splom2(x, expr.arr)


On 2011-04-20, at 01:33 , baptiste auguie wrote:

> Hi,
> 
> You may want to wait advice from someone who actually understands (the
> labyrinth that is) lattice's help for splom, but the following might
> be a start. I didn't understand what values you actually wanted
> displayed in the lower triangle panels, so I made up some random ones
> in a 3x3 matrix of 3-vectors.
> 
> library(lattice)
> library(gridExtra)
> 
> info <- function(x){
>  grid.table(c(bquote(italic(a)==.(x[1])),
>               bquote(italic(b)==.(x[2])),
>               bquote(italic(c)==.(x[3]))),
>             core.just="left",
>             parse=TRUE)
> }
> 
> U <- matrix(runif(3000), ncol=3)
> 
> splom(U,
>     superpanel=function(z, ...){
>       ## dummy 3x3 matrix of 3 values to diplay
>       values <- replicate(9, round(rnorm(3), 3), simplify=FALSE)
>       dummy <- matrix(values, ncol=3, byrow=F)
>       panel.pairs(z, upper.panel=panel.splom,
>                   lower.panel=function(i, j, ...){
>                     print(paste(i,j)) # current panel indices
>                     info(dummy[i,j] [[1]]) # access the list elements
>                   }, ...)
>       })
> 
> HTH,
> 
> baptiste
> 
> 
> On 20 April 2011 10:17, Marius Hofert <m_hofert at web.de> wrote:
>> Dear Baptiste,
>> 
>> there is one tricky part left: how can I create a matrix with the grid.table()
>> objects as output? Is this possible? If not, maybe one can try to work with
>> panel.splom (which can address single panels and thus call info() for each
>> row-column index pair (i,j)), but I'm not sure if this will work.
>> 
>> Cheers,
>> 
>> Marius
>> 
>> library(lattice)
>> library(gridExtra)
>> 
>> splom2 <- function(x, a, b, c){
>>    ## function for the additional information
>>    info <- function(a., b., c.){ # single values for one panel
>>        grid.table(c(bquote(italic(a)==.(a.)),
>>                     bquote(italic(b)==.(b.)),
>>                     bquote(italic(c)==.(c.))
>>                     ),
>>                   parse=TRUE, # parse labels as expressions
>>                   theme=theme.list(
>>                   gpar.corefill=gpar(fill=NA, col=NA), # make bg transparent
>>                   core.just="right") # justification of labels
>>                   )
>>    }
>>    labs <- matrix(, nrow=ncol(x), ncol=ncol(x)) # should be a matrix of grid.table() objects
>>    for(i in 1:ncol(x)) for(j in 1:ncol(x)) labs[i,j] <- info(a.=a[i,j], b.=b[i,j], c.=c[i,j])
>>    ## splom
>>    splom(x, superpanel=function(z,...){
>>              df=data.frame(rows=as.vector(row(a)),
>>              columns=as.vector(col(a)), labs=as.vector(labs))
>>              df=subset(df,columns<rows) # subset for lower left triangle
>>              with(df,{
>>                  panel.text(x=rows, y=columns, labels=labs)
>>              })
>>              panel.pairs(z, upper.panel=panel.splom, lower.panel=function(...){}, ...)
>>          })
>> }
>> 
>> ## generate data
>> U <- matrix(runif(3000), ncol=3)
>> 
>> ## build information
>> a <- cor(U, method="kendall")
>> b <- diag(ncol=3, nrow=3)
>> c <- diag(ncol=3, nrow=3)
>> 
>> ## plot with information
>> splom2(U, a, b, c)
>> 
>> 
>>