Re: how to write ParallelSubmit in a Do loop? trying to use up all CPU

*To*: undisclosed-recipients:;*Subject*: [mg131455] Re: how to write ParallelSubmit in a Do loop? trying to use up all CPU*From*: Sseziwa Mukasa <mukasa at gmail.com>*Date*: Tue, 9 Jul 2013 06:50:09 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net*References*: <20130708032047.1772769BF@smc.vnet.net>

First of all, Do always returns Null, but the assignment still happened, evaluate job[0] to check. However for your computation to work you need to distribute the definition of step and enclose the local value of i in ParallelSubmit: t = AbsoluteTime[]; initial = 1 final = 20000000 step = (final - initial + 1)/8 Clear["job"] Clear["i"] DistributeDefinitions[step] Do[job[i]=ParallelSubmit[{i},Table[Prime[k], {k, step*i + 1, step*(i + 1)}]] , {i, 0, 7}] Clear["a"] Table[a[jj], {jj, 1, 8}] = WaitAll[Table[job[j], {j, 0, 7}]] time2 = AbsoluteTime[] - t Regards, Sseziwa On Jul 7, 2013, at 11:20 PM, alex <0899607 at gmail.com> wrote: > when it comes a heavily calculation, it takes time, but not fully cpu usage > i found a scrip using ParallelSubmit, which is quite powerful and really shorten the time in calculating > > = http://mathematica.stackexchange.com/questions/10969/parallelization-problem-in-linearsolve-and-minimize > > > t = AbsoluteTime[]; > job1 = ParallelSubmit[Table[Prime[k], {k, 1, 2500000}]]; > job2 = ParallelSubmit[Table[Prime[k], {k, 2500001, 5000000}]]; > job3 = ParallelSubmit[Table[Prime[k], {k, 5000001, 7500000}]]; > job4 = ParallelSubmit[Table[Prime[k], {k, 7500001, 10000000}]]; > job5 = ParallelSubmit[Table[Prime[k], {k, 10000001, 12500000}]]; > job6 = ParallelSubmit[Table[Prime[k], {k, 12500001, 15000000}]]; > job7 = ParallelSubmit[Table[Prime[k], {k, 15000001, 17500000}]]; > job8 = ParallelSubmit[Table[Prime[k], {k, 17500001, 20000000}]]; > {a1, a2, a3, a4, a5, a6, a7, a8} = > WaitAll[{job1, job2, job3, job4, job5, job6, job7, job8}]; > time2 = AbsoluteTime[] - t > > t = AbsoluteTime[]; > > > > > > then i try to rewrite the script by using Do loop, so i can just setup the initial and final value then it can be separated into 8 parts automatically , but i failed. > > > t = AbsoluteTime[]; > initial = 1 > final = 20000000 > step = (final - initial + 1)/8 > Clear["job"] > Clear["i"] > > Do[job[i]=ParallelSubmit[Table[Prime[k], {k, step*i + 1, step*(i + 1)}]] > , {i, 0, 7}] > > Clear["a"] > Table[a[jj], {jj, 1, 8}] = WaitAll[Table[job[j], {j, 0, 7}]] > > time2 = AbsoluteTime[] - t > > > > it keeps showing Null, it seems that it cant replace the variable in Do loop exactly, it is still a variable. > > how do i rewrite the scrip? to make it be separated into 8 parts automatically? > thank you for your help ^^ >

**References**:**how to write ParallelSubmit in a Do loop? trying to use up all CPU***From:*alex <0899607@gmail.com>