[BioC] multicore and GRangesList [Resurrected]

[Cook, Malcolm]

The question of approaches to parallelizing operations on a GRangesList was raised in this thread:  http://thread.gmane.org/gmane.science.biology.informatics.conductor/32799

I find the issue still relevant when using the new `parallel` package.

I have adopted the following practice, for which I seek your criticism or accolades.  Your choice.

The approach is to use parallel::pvec over the indices of the GRangesList, with a little sugar in the form of...

pvec_along <-function(x,FUN,...) {
### PURPOSE: extension to parallel::pvec for non-vectors which is
### vectorized over the indices of x.
###
### Example: pvec_along(myGRangesList,width)
###
### Requires: `library(functional)` `library(parallel)`
  indices<-seq_along(x)
  FUN<-match.fun(FUN)
  pvec(indices,Compose(Curry(`[`,x),FUN),...)
}

Discuss?

Best,

~ Malcolm Cook