> 1. matrices are stored columnwise so R is better at column-wise operations
> than row-wise.
I am seeing this by my code which contains more t() than
what seems healthy. However, the summaries are patient-wise
over repeated measurements. Out of convention, I am storing
patients in rows and measur
1. matrices are stored columnwise so R is better at column-wise operations
than row-wise.
2. Here is one way to do it (although I am not sure its better than the
index approach):
row.apply <- function(f, a, b)
t(mapply(f, as.data.frame(t(a)), as.data.frame(t(b
3. The code for the ex
[Apologies to Gabor, who I sent a personal copy of the reply
erroneously instead of posting to List directly]
[...]
> Perhaps what you really intend is to
> take the average over those elements in each row of the first matrix
which correspond to 1's in the second in the corresponding
> row of the
