How do I compile and run this parallel program? Michael =========================== import Control.Parallel nfib :: Int -> Int nfib n | n <= 1 = 1        | otherwise = par n1 (seq n2 (n1 + n2 + 1))                      where n1 = nfib (n-1)                            n2 = nfib (n-2) {- nfib :: Int -> Int nfib n | n <= 1 = 1        | otherwise = nfib (n-1) + nfib (n-2) -} main = do putStrLn $ show $ nfib 39 =========================== [michael@hostname ~]$ ghc --make -threaded nfib.hs [michael@hostname ~]$ ./nfib +RTS -N3 nfib: the flag -N3 requires the program to be built with -threaded nfib:  nfib: Usage: <prog> <args> [+RTS <rtsopts> | -RTS <args>] ... --RTS <args> nfib:  nfib:    +RTS    Indicates run time system options follow nfib:    -RTS    Indicates program arguments follow nfib:   --RTS    Indicates that ALL subsequent arguments will be given to the nfib:            program (including any of these RTS flags) nfib:  nfib: The following run time system options are available: nfib:  nfib:   -?       Prints this message and exits; the program is not executed nfib:   --info   Print information about the RTS used by this program nfib:  nfib:   -K<size> Sets the maximum stack size (default 8M)  Egs: -K32k   -K512k nfib:   -k<size> Sets the initial thread stack size (default 1k)  Egs: -k4k   -k2m nfib:  nfib:   -A<size> Sets the minimum allocation area size (default 512k) Egs: -A1m -A10k nfib:   -M<size> Sets the maximum heap size (default unlimited)  Egs: -M256k -M1G nfib:   -H<size> Sets the minimum heap size (default 0M)   Egs: -H24m  -H1G nfib:   -m<n>    Minimum % of heap which must be available (default 3%) nfib:   -G<n>    Number of generations (default: 2) nfib:   -T<n>    Number of steps in younger generations (default: 2) nfib:   -c<n>    Use in-place compaction instead of copying in the oldest generation nfib:            when live data is at least <n>% of the maximum heap size set with nfib:            -M (default: 30%) nfib:   -c       Use in-place compaction for all oldest generation collections nfib:            (the default is to use copying) nfib:   -w       Use mark-region for the oldest generation (experimental) nfib:  nfib:   -t[<file>] One-line GC statistics (if <file> omitted, uses stderr) nfib:   -s[<file>] Summary  GC statistics (if <file> omitted, uses stderr) nfib:   -S[<file>] Detailed GC statistics (if <file> omitted, uses stderr) nfib:  nfib:  nfib:   -Z       Don't squeeze out update frames on stack overflow nfib:   -B       Sound the bell at the start of each garbage collection nfib:  nfib:   -hT      Heap residency profile (output file <program>.hp) nfib:   -i<sec>  Time between heap samples (seconds, default: 0.1) nfib:  nfib:   -C<secs>  Context-switch interval in seconds. nfib:             0 or no argument means switch as often as possible. nfib:             Default: 0.02 sec; resolution is set by -V below. nfib:   -V<secs>  Master tick interval in seconds (0 == disable timer). nfib:             This sets the resolution for -C and the profile timer -i. nfib:             Default: 0.02 sec. nfib:  nfib:   --install-signal-handlers=<yes|no> nfib:             Install signal handlers (default: yes) nfib:  nfib: RTS options may also be specified using the GHCRTS environment variable. nfib:  nfib: Other RTS options may be available for programs compiled a different way. nfib: The GHC User's Guide has full details. nfib:  [michael@hostname ~]$