Re: Re: ParrallelDo and set::noval

*To*: mathgroup at smc.vnet.net*Subject*: [mg102704] Re: [mg102697] Re: ParrallelDo and set::noval*From*: Patrick Scheibe <pscheibe at trm.uni-leipzig.de>*Date*: Thu, 20 Aug 2009 04:55:30 -0400 (EDT)*References*: <h63cgg$1b6$1@smc.vnet.net> <h6duf8$h1c$1@smc.vnet.net>

Hi, why do you create the table in the first place? Just let ParallelTable collect your data: grid = Range[4, 50, 0.5]; DistributeDefinitions[grid]; testArray1 = ParallelTable[ {i, If[4 <= grid[[i]] <= 50, 1, 0]}, {i, 1, Length[grid]}] but if you insist to know what was wrong with your code, please have a look at SetSharedVariable[...] grid = Range[4, 50, 0.5]; testArray = Array[Null, {Length[grid]}]; DistributeDefinitions[grid]; SetSharedVariable[testArray]; ParallelDo[iroot = 0; rr = grid[[i]]; Which[4 <= rr <= 50, iroot = 1]; testArray[[i]] = {i, iroot};, {i, 1, Length[grid]}] testArray===testArray1 Out[12]= True Cheers Patrick On Wed, 2009-08-19 at 07:02 -0400, guerom00 wrote: > As requested, a minimal example which illustrate the problem. > > The following sequential code works fine : > > grid = Range[4, 50, 0.5]; > testArray = Array[Null, {Length[grid]}]; > > Do[ > iroot = 0; > rr = grid[[i]]; > Which[ > 4 <= rr <= 50, iroot = 1 > ]; > testArray[[i]] = {i, iroot}; > , {i, 1, Length[grid]}] > > > The equivalent parallel code : > > grid = Range[4, 50, 0.5]; > testArray = Array[Null, {Length[grid]}]; > > DistributeDefinitions[grid,testArray]; > > ParallelDo[ > iroot = 0; > rr = grid[[i]]; > Which[ > 4 <= rr <= 50, iroot = 1 > ]; > testArray[[i]] = {i, iroot}; > , {i, 1, Length[grid]}] > > returns "Set::noval: Symbol testArray in part assignment does not have > an immediate value." Somehow the DistributeDefinitions[] is not > sufficient to indicate to each kernel that I have initialized the list > testArray. > > Thanks in advance for any help :) >