How many worker threads did you start? Can you make D a SharedArray or
DArray?

On Sat Jan 31 2015 at 10:55:51 AM Paul Analyst <[email protected]>
wrote:

> Realy ? Is imposibly smoething like :
>   take 1. column and copmute on 1. core, wihout waiting for end of 1.
> oparation take 2. column and copmpute on 2. cores .etc.... ?
> Paul
>
> W dniu 2015-01-31 o 16:32, Tim Holy pisze:
> > Paul, until the "threads" branch gets merged, I recommend that you just
> accept
> > the fact that you'll only have 1 core active for most operations.
> >
> > --Tim
> >
> > On Saturday, January 31, 2015 07:15:25 AM paul analyst wrote:
> >> Thx, but, no.
> >> For sparse matrix 10^5,10^4,0.002 is the same . Time for both whiles is
> >> about 48 sek, only 11% o cores is used. I vave 8 cores, 7 sleeps:/
> >> Paul
> >>
> >> W dniu sobota, 31 stycznia 2015 15:50:02 UTC+1 użytkownik Sam Kaplan
> >>
> >> napisał:
> >>> Hi Paul,
> >>>
> >>> If D is allocated on the master, then Julia will need to pass D from
> the
> >>> master to the workers.  I'm guessing that this communication might be
> more
> >>> expensive than the compute in your loops.  It may be useful to take a
> look
> >>> at distributed arrays in the parallel section of the Julia docs.
> >>>
> >>> Hope it helps.
> >>>
> >>> Sam
> >>>
> >>> On Saturday, January 31, 2015 at 7:38:22 AM UTC-6, paul analyst wrote:
> >>>> Parallel loop, what wroong ? Parallel is slower then normal
> >>>>
> >>>> julia> @time for i=1:l
> >>>>
> >>>>         w[i]=var(D[:,i])
> >>>>         end
> >>>>
> >>>> elapsed time: 4.443197509 seconds (14074576 bytes allocated)
> >>>>
> >>>>
> >>>> julia> @time ww=@parallel (hcat) for i=1:l
> >>>>
> >>>>         var(D[:,i])
> >>>>         end
> >>>>
> >>>> elapsed time: 5.287007403 seconds (435449580 bytes allocated, 5.00% gc
> >>>> time)
> >>>> 1x10000 Array{Float64,2}:
> >>>>
> >>>> Paul
> >>>>
> >>>> julia> @time for i=1:l
> >>>>
> >>>>         w[i]=var(D[:,i])
> >>>>         end
> >>>>
> >>>> elapsed time: 4.331569152 seconds (8637464 bytes allocated)
> >>>>
> >>>> julia> @time ww=@parallel (hcat) for i=1:l
> >>>>
> >>>>         var(D[:,i])
> >>>>         end
> >>>>
> >>>> elapsed time: 4.908234336 seconds (422121448 bytes allocated, 4.85% gc
> >>>> time)
> >>>>
> >>>> 1x10000 Array{Float64,2}:
> >>>>   0.000703737  0.000731674  0.000582672  0.00080388    0.000759479
> >>>>
> >>>> 0.000402509  0.0007118  0.000989408
> >>>>
> >>>> julia> size(D)
> >>>> (10000,10000)
>
>

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