ParallelTable[ ]

*To*: mathgroup at smc.vnet.net*Subject*: [mg100768] ParallelTable[ ]*From*: "Scot Martin" <smartin at seas.harvard.edu>*Date*: Sat, 13 Jun 2009 06:04:21 -0400 (EDT)*Organization*: Harvard University*Reply-to*: <scot_martin at harvard.edu>

Just started looking at the parallel computing. This seems a very good option for me because any "long" calculations I have are usually tied to list manipulation. For background,$ProcessorCount returns "2" on my machine. I tried this command: AbsoluteTiming[ParallelTable[i^2, {i, 1000000}]] The required time was 9.28 s. I followed with this command: AbsoluteTiming[Table[i^2, {i, 1000000}]] The requied time was 0.86 s. So, you can imagine my confusion. Can anyone explain why parallel table generation took 10 times as long? [Incidentally and perhaps related, the command of Timing[ParallelTable[i^2, {i, 1000000}]] takes 0.078 s. This leaves me very confused because the computer obviously take much longer to execute, i.e., I am sitting at my console for closer to 9.28 s than 0.078 s. The command of Timing[Table[i^2, {i, 1000000}]] takes 0.875 s. What gives?] Looking forward to everyone's insights!