It appears that you are not using a fast BLAS. The BLAS and LAPACK entries
in versioninfo() should say libopenblas instead of libblas and liblapack.
You should use

https://launchpad.net/~staticfloat/+archive/ubuntu/juliareleases

as your repo for julia. That should give you Julia with fast linear algebra.

Med venlig hilsen

Andreas Noack

2014-09-25 10:36 GMT-04:00 Ján Dolinský <[email protected]>:

> Hello,
>
> Yes, Andreas point makes sense. Sometimes you may not want threaded linear
> algebra routines.
>
> My current installation reports this:
> versioninfo()
> Julia Version 0.3.0
> Commit 7681878 (2014-08-20 20:43 UTC)
> Platform Info:
>   System: Linux (x86_64-linux-gnu)
>   CPU: Intel(R) Core(TM) i5-4300U CPU @ 1.90GHz
>   WORD_SIZE: 64
>   BLAS: libblas.so.3
>   LAPACK: liblapack.so.3
>   LIBM: libopenlibm
>   LLVM: libLLVM-3.3
>
> Am I using the right library ? How do I plug-in the OpenBLAS ? I am under
> Ubuntu 14.4.01.
>
> Thanks,
> Jan
>
> Dňa štvrtok, 25. septembra 2014 14:47:12 UTC+2 Andreas Noack napísal(-a):
>>
>> OpenBLAS uses threads by default, but Milan reported that Fedora's
>> maintainer had them disabled. Hence, unless you are using Fedora, you
>> should have threaded OpenBLAS.
>>
>> What is the best setup for fast linear algebra operations ?
>>
>>
>> That question doesn't have a single answer. Often when people want to
>> show performance of linear algebra libraries they run a single routine on a
>> big matrix. In that case you'll often benefit from many threads. However,
>> in many applications you solve smaller problems many times. In this case,
>> many threads can actually be a problem and you could be better off with
>> turning off OpenBLAS threading. So it depends on your problem.
>>
>> Med venlig hilsen
>>
>> Andreas Noack
>>
>> 2014-09-25 5:52 GMT-04:00 Ján Dolinský:
>>
>>> Hello,
>>>
>>> How do I make Julia to use threaded version of OpenBLAS ? Do I have to
>>> compile using some special option or there is a config file ?
>>> What is the best setup for fast linear algebra operations ?
>>>
>>> Best Regards,
>>> Jan
>>>
>>> Dňa nedeľa, 21. septembra 2014 9:50:52 UTC+2 Stephan Buchert napísal(-a):
>>>
>>>> Wow, I have now LU a little bit faster on the latest julia Fedora
>>>> package than on my locally compiled julia:
>>>>
>>>> julia> versioninfo()
>>>> Julia Version 0.3.0
>>>> Platform Info:
>>>>   System: Linux (x86_64-redhat-linux)
>>>>   CPU: Intel(R) Core(TM) i7-4700MQ CPU @ 2.40GHz
>>>>   WORD_SIZE: 64
>>>>   BLAS: libopenblas (DYNAMIC_ARCH NO_AFFINITY Haswell)
>>>>   LAPACK: libopenblasp.so.0
>>>>   LIBM: libopenlibm
>>>>   LLVM: libLLVM-3.3
>>>>
>>>> julia> include("code/julia/bench.jl")
>>>> LU decomposition, elapsed time: 0.07222901 seconds, was 0.123 seconds
>>>> with my julia
>>>> FFT             , elapsed time: 0.248571629 seconds
>>>>
>>>> Thanks for making and  improving the Fedora package
>>>>
>>>
>>

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