并行计算问题

Question

I seem to have run on a problem when trying to run a parallel computing in R

library(parallel)
library(foreach)
library(doParallel)
library(snow)
cl <- makeCluster(detectCores())
Loading required package: Rmpi
Error : .onLoad failed in loadNamespace() for 'Rmpi', details:
call: inDL(x, as.logical(local), as.logical(now), ...)
error: unable to load shared object 'C:/Users/PCCasa/Documents/R/win-   library/3.2/Rmpi/libs/x64/Rmpi.dll':
LoadLibrary failure:  The system is unable to find the package specified.

Error in makeMPIcluster(spec, ...) : 
the `Rmpi' package is needed for MPI clusters.
registerDoParallel(cl)
Error in registerDoParallel(cl) : Object 'cl' not found

windowsproduces an error which advises to either repair or reinstall msmpi.dll. Could you kindly let me know what the best prodecure would be as to solve this issue

Answer 1

None, the RMPI spawn function is not implemented for Windows. Here is the excerpt of the RMPI code.

if (.Platform$OS=="windows"){
    #stop("Spawning is not implemented. Please use mpiexec with Rprofile.")
    workdrive <- unlist(strsplit(getwd(),":"))[1]
    workdir <- unlist(strsplit(getwd(),"/"))
    if (length(workdir) > 1)
        workdir <-paste(workdir, collapse="\\")
    else
        workdir <- paste(workdir,"\\")
    localhost <- Sys.getenv("COMPUTERNAME")
    networkdrive <-NULL #.Call("RegQuery", as.integer(2),paste("NETWORK\\",workdrive,sep=""), 
                    #PACKAGE="Rmpi")
    remotepath <-networkdrive[which(networkdrive=="RemotePath")+1]
    mapdrive <- as.logical(mapdrive && !is.null(remotepath))
    arg <- c(Rscript, R.home(), workdrive, workdir, localhost, mapdrive, remotepath)
    if (.Platform$r_arch == "i386") 
        realns <- mpi.comm.spawn(slave = system.file("Rslaves32.cmd", 
            package = "Rmpi"), slavearg = arg, nslaves = nslaves, 
            info = 0, root = root, intercomm = intercomm, quiet = quiet)
    else 
        realns <- mpi.comm.spawn(slave = system.file("Rslaves64.cmd", 
                    package = "Rmpi"), slavearg = arg, nslaves = nslaves, 
            info = 0, root = root, intercomm = intercomm, quiet = quiet)
}