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OpenBLAS crashes on Ubuntu 15.04

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  1. Nov 7, 2015 #1
    Whenever I try to reduce, invert, or factorize matrices of size 10000x10000 my whole system suddenly restarts without any error message. This happens on both julia and matlab when I run the command A=rand(10000,10000)^-1;

    I suspect the problem is due to the linear algebra libraries (I have openblas 0.2.12-1 and lapack 3.5.0-4). I'm running Ubuntu 15.04 on an Intel Core i7-4790K, 2x8GB RAM Kingston Fury, Asus Z97-P motherboard, and NVIDIA 980 GTX gpu.

    Help please, and thanks.
     
  2. jcsd
  3. Nov 7, 2015 #2

    Svein

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    Science Advisor

    It may very well be the size of your matrix - it is slightly less than 1Gbyte in size. Try with a 100x100 matrix first and see if it still crashes.
     
  4. Nov 7, 2015 #3
    It does not crash with small matrices, it can work well with 1000. My windows laptop with lower specs can work with those large sizes.
     
  5. Nov 8, 2015 #4

    Svein

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    Let me guess - you are running a 64bit version of Windows on your laptop and 32bit version of Ubuntu...
     
  6. Nov 8, 2015 #5
    Both are 64bit OS running on 64bit machines. It seems that the problem is not present when using octave.
     
    Last edited: Nov 8, 2015
  7. Nov 8, 2015 #6

    jim mcnamara

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    Staff: Mentor

    What you have on Ubuntu is called a kernel panic - usually from corruption of
    kernel data often due to a programming error in user space piddling in kernel space.

    The linux command
    Code (Text):
    free
    will show you how much memory is in use at
    any given time. Normally, a single user systems will have about 90% of memory
    free - note that those buffers you see come and go dynamically

    From the man7.org man page information on the free(1) command
    Now you have a tool.

    Your matrix is a lot larger than mentioned before. 64 (bits in a signed
    integer) * 10000 *10000 is ~6.4GB, with 80 bits in a double precision floating
    point varable it is ~8.0GB. Math packages tend to use existing numeric formats
    unless you are using extended precision - like in GMP.

    The free tool will give you available. If you need more memory you will have to add swap space.
    Virtual memory = swap (paging) file size plus memory. This is temporary fix.
    Add more RAM is another possibility but has a monetary penalty.

    Also consider letting the people who support the problem software packages know
    of the issue. This is important in the long run.

    Since octave does not exhibit the problem use it instead if the above is too
    much of a problem. But still consider reporting the problem.
     
  8. Nov 9, 2015 #7

    Svein

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    Science Advisor

    Umm - 64bits = 8bytes...
     
  9. Nov 9, 2015 #8

    jim mcnamara

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    Staff: Mentor

    Thank you - you are absolutely right.
     
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