I don't know why you get that error. It is not there on my machine.
However, for some reason defining k as const does not work for parallel
loops. It only makes a difference for serial loops so my explanation was
wrong. Is this expected?
julia> const k1=10000000;k2 = k1;
julia> @time for i = 1:10000000
int(randbool())
end
elapsed time: 0.041954142 seconds (0 bytes allocated)
julia> @time for i = 1:k1
int(randbool())
end
elapsed time: 0.042543885 seconds (0 bytes allocated)
julia> @time for i = 1:k2
int(randbool())
end
elapsed time: 2.923224821 seconds (639983688 bytes allocated)
julia> @time tmp = @parallel (+) for i = 1:10000000
int(randbool())
end
elapsed time: 0.05594257 seconds (155072 bytes allocated)
julia> @time tmp = @parallel (+) for i = 1:k1
int(randbool())
end
elapsed time: 3.067074328 seconds (640486512 bytes allocated)
julia> @time tmp = @parallel (+) for i = 1:k2
int(randbool())
end
elapsed time: 3.021796716 seconds (640090424 bytes allocated)
2014-06-01 16:28 GMT+02:00 paul analyst <[email protected]>:
> After restart julia :
>
>
> D:\install\Julia\Julia 0.3.0-prerelease-win64-ver3\Julia 0.3.0-prerelease
> ver 3>bin\julia.exe -p 8
> _
> _ _ _(_)_ | A fresh approach to technical computing
> (_) | (_) (_) | Documentation: http://docs.julialang.org
> _ _ _| |_ __ _ | Type "help()" to list help topics
> | | | | | | |/ _` | |
> | | |_| | | | (_| | | Version 0.3.0-prerelease+2599 (2014-04-11 23:52
> UTC)
> _/ |\__'_|_|_|\__'_| | Commit bf7096c (50 days old master)
> |__/ | x86_64-w64-mingw32
>
> julia> const k=200000000
>
> 200000000
>
> julia> tic();
>
> julia> nheads = @parallel (+) for i=1:k
> int(randbool())
> end
> exception on exception on 3: 4: ERROR: ERROR: exception on exception on 2:
> exception on 7: ERROR: 5:
> ERROR: ERROR: exception on k not defined6: exception on ERROR:
> in anonymous at no file:1379
> 8k: not definedERROR:
> in anonymous at no file:1379
> k not definedk not defined
> in anonymous at no file:1379
>
> in anonymous at no file:1379
> k not definedk not definedk not defined
> in anonymous at no file:1379
>
> in anonymous at no file:1379
>
> in anonymous at no file:1379exception on
> 9: ERROR: k not defined
> in anonymous at no file:1379
> ERROR: no method +(UndefVarError, UndefVarError)
> in mr_pairwise at reduce.jl:534
>
> julia> toc()
> elapsed time: 2.493525081 seconds
> 2.493525081
>
> julia>
>
> W dniu niedziela, 1 czerwca 2014 16:27:14 UTC+2 użytkownik paul analyst
> napisał:
>
>>
>>
>>
>>
>> *julia> const k=200000000;ERROR: cannot declare k constant; it already
>> has a value:/Paul*
>> W dniu niedziela, 1 czerwca 2014 16:13:27 UTC+2 użytkownik Andreas Noack
>> Jensen napisał:
>>>
>>> This is the usual problem with global variables in Julia. If you define
>>> k by
>>>
>>> const k=200000000
>>>
>>> the timing results should be similar.
>>>
>>>
>>> 2014-06-01 16:09 GMT+02:00 paul analyst <[email protected]>:
>>>
>>>>
>>>> D:\install\Julia\Julia 0.3.0-prerelease-win64-ver3\Julia
>>>> 0.3.0-prerelease ver 3>bin\julia.exe -p 8
>>>> _
>>>> _ _ _(_)_ | A fresh approach to technical computing
>>>> (_) | (_) (_) | Documentation: http://docs.julialang.org
>>>> _ _ _| |_ __ _ | Type "help()" to list help topics
>>>> | | | | | | |/ _` | |
>>>> | | |_| | | | (_| | | Version 0.3.0-prerelease+2599 (2014-04-11
>>>> 23:52 UTC)
>>>> _/ |\__'_|_|_|\__'_| | Commit bf7096c (50 days old master)
>>>> |__/ | x86_64-w64-mingw32
>>>>
>>>> julia> procs()
>>>> 9-element Array{Int64,1}:
>>>> 1
>>>> 2
>>>> 3
>>>> 4
>>>> 5
>>>> 6
>>>> 7
>>>> 8
>>>> 9
>>>>
>>>> julia> tic();
>>>>
>>>> julia> nheads = @parallel (+) for i=1:200000000
>>>> int(randbool())
>>>> end
>>>> 100006468
>>>>
>>>> julia> toc()
>>>> elapsed time: 2.77418807 seconds
>>>> 2.77418807
>>>>
>>>> julia>exit()
>>>>
>>>>
>>>> D:\install\Julia\Julia 0.3.0-prerelease-win64-ver3\Julia
>>>> 0.3.0-prerelease ver 3>bin\julia.exe -p 8
>>>> _
>>>> _ _ _(_)_ | A fresh approach to technical computing
>>>> (_) | (_) (_) | Documentation: http://docs.julialang.org
>>>> _ _ _| |_ __ _ | Type "help()" to list help topics
>>>> | | | | | | |/ _` | |
>>>> | | |_| | | | (_| | | Version 0.3.0-prerelease+2599 (2014-04-11
>>>> 23:52 UTC)
>>>> _/ |\__'_|_|_|\__'_| | Commit bf7096c (50 days old master)
>>>> |__/ | x86_64-w64-mingw32
>>>>
>>>> julia> k=200000000
>>>> 200000000
>>>>
>>>> julia> tic();
>>>>
>>>> julia> nheads = @parallel (+) for i=1:k
>>>> int(randbool())
>>>> end
>>>> 99989022
>>>>
>>>> julia> toc()
>>>> elapsed time: 18.631674663 seconds
>>>> 18.631674663
>>>>
>>>> julia>
>>>>
>>>> What hapend ?
>>>>
>>>> Paul
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Med venlig hilsen
>>>
>>> Andreas Noack Jensen
>>>
>>
--
Med venlig hilsen
Andreas Noack Jensen
