[R-sig-Geo] raster::clump not working?

[João Carreiras]

Hi!

I've been trying to run the clump command but the output is consistently a
raster with values == 1. Please find below an example.

I'm sure I'm doing something stupid. However, the command is really
straightforward and I can't seem to identify what the problem might be.

Any help really appreciated.
Thanks
Joao

r <- raster(ncols=36, nrows=18)
x <- init(r, fun='cell')
x
class       : RasterLayer
dimensions  : 18, 36, 648  (nrow, ncol, ncell)
resolution  : 10, 10  (x, y)
extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0
data source : in memory
names       : layer
values      : 1, 648  (min, max)
a <- clump(x)
a
class       : RasterLayer
dimensions  : 18, 36, 648  (nrow, ncol, ncell)
resolution  : 10, 10  (x, y)
extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0
data source : in memory
names       : clumps
values      : 1, 1  (min, max)