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2005 Aug 08
1
modifying argument of a .C call (DUP=FALSE)
...ransformation. Two of these matrices cannot fit in the memory, so I cannot
do this in R.
I thought of writing some C code to do this and calling it using .C with
DUP=FALSE. All I need is a simple for loop that replaces elements with
their new value, something like
void transform(double *a, int *lengtha) {
int i;
for (i=0; i < *lengtha; i++) {
*(a+i) = calculatenewvaluesomehow(*(a+i))
}
}
trans <- function(a) .C("transform",as.double(a), as.integer(length(a))
is it possible to do this? The manuals say that it is dangerous, is it
possible to avoid the dangers somehow?...