On Wed, 16 Feb 2005 15:44:00 +0200, Sander Oom <[EMAIL PROTECTED]> wrote :
>Thanks Peter! > >Of course I only have (nx-1)(ny-1) facets in a x*y plot! > >The help page line: >... >col the color(s) of the surface facets. Transparent colours are >ignored. This is recycled to the (nx-1)(ny-1) facets. >... >just did not ring a bell. > >In fact, it is still not clear to me why it recycles the ramp even >though it has a surplus of colours (grey levels)! Why not just ignore >the surplus colours? Your z array is 6 by 7. Your cols will be mapped to a 5 by 6 array. They don't look like an array, because the grey() function stripped off the dimension attribute. The problem is that if you pass the entries from a 6 by 7 array to something that expects the entries from a 5 by 6 array, you get things in the wrong order. You see the same effect here: > rownum <- as.vector(row(matrix(NA, 6, 7))) > matrix(rownum, 6, 7) [,1] [,2] [,3] [,4] [,5] [,6] [,7] [1,] 1 1 1 1 1 1 1 [2,] 2 2 2 2 2 2 2 [3,] 3 3 3 3 3 3 3 [4,] 4 4 4 4 4 4 4 [5,] 5 5 5 5 5 5 5 [6,] 6 6 6 6 6 6 6 > matrix(rownum, 5, 6) [,1] [,2] [,3] [,4] [,5] [,6] [1,] 1 6 5 4 3 2 [2,] 2 1 6 5 4 3 [3,] 3 2 1 6 5 4 [4,] 4 3 2 1 6 5 [5,] 5 4 3 2 1 6 Warning message: data length [42] is not a sub-multiple or multiple of the number of rows [5] in matrix except that in this case you get a warning about the wrong length; persp doesn't give you the warning. Maybe it should? Duncan Murdoch ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html