[R-sig-Geo] Problem with raster calculation

[Aidin Niamir]

Dear all

I am experiencing a strange problem when calculating in the raster package.
Let me explain it with a simple example;

> a <- c(1,1,1,0,0,0,2,2,2)
> a <- matrix(a,3,3,byrow=T)
> a <- raster(a)
> a []
[1] 1 1 1 0 0 0 2 2 2
> b <- 10 - a
> b []
[1]  -9  -9  -9 -10 -10 -10  -8  -8  -8

As you can see, the obtained values are not correct. I cannot see why
this should be.
Can anybody help?

Aidin Niamir