R help - Jul 2010 - xyplot of function only shows diagonal plots

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?

--- 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 ---

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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