[R] xyplot of function only shows diagonal plots

[Deepayan Sarkar]

On Wed, Jul 7, 2010 at 12:17 PM, DrHatch <DrHatch at patandhatch.org> wrote:
> I expected this script to show nine panels, each with a plot of the
> function.
> But when I run it, only the diagonal panels have content.
> Executing > print(trel_1) shows what I expected in the upper left corner.
> I am using R ver. 2.11.0 and lattice ver. 0.18-8 on Windows XP under Eclipse
> and StatET.
> I have searched the documentation, but found no answer. What am I missing?

That you haven't created all the (a, b) combinations you want: you are
plotting these combinations

 > cbind(a, b)
     a b
[1,] 1 1
[2,] 2 2
[3,] 3 3

when you actually want these:

> expand.grid(a = a, b = b)
  a b
1 1 1
2 2 1
3 3 1
4 1 2
5 2 2
6 3 2
7 1 3
8 2 3
9 3 3

-Deepayan

>
> --- simple.R ---
>
> # Test xyplot layout for a function
> #
> require("lattice")
>
>   f <- function(x,a,b){return( a * sin(x)+ b)}
>   trellis.par.set(theme = canonical.theme("Windows"))
>   x <- seq(-4,4, by=0.1)
> # case 1x1
>   a <- c( 1 )
>   b <- c( 3 )
>   trel_1 <- xyplot(f(x,a,b) ~ x | a * b, ,  type = "l",             main =
> "1x1", ylab = "f(x)", xlab = "x",
>           xlim = c(-6,6), ylim = c(-6,6),   )
> # case 3x3
>   a <- c(1,2,3)
>   b <- c(1,2,3)
>   trel_3 <- xyplot(f(x,a,b) ~ x | a * b, ,  type = "l",
> main = "3x3", ylab = "f(x)", xlab = "x",
>                   xlim = c(-6,6), ylim = c(-6,6),   )
>
> print(trel_3)
> #print(trel_1)
>
> --- end of simple.R ---
>
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