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 High Performance Computing Linpack Benchmark (HPL)
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 HPL 2.0 - September 10, 2008
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 History
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 - 09/09/00 Public release of Version 1.0
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 - 09/27/00 A couple of mistakes in the  VSIPL  port have been
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 corrected.  The tar file as well as the web site were updated
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 on September 27th, 2000.  Note  that  these problems were not
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 affecting the BLAS version of the software in any way.
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 - 01/01/04 Version 1.0a
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 The  MPI  process grid  numbering  scheme  is now an run-time
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 option.
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 The inlined assembly  timer  routine that caused the compila-
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 tion to fail when using  gcc  version 3.3  and above has been
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 removed from the package.
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 Various building problems on the T3E have been fixed;  Thanks
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 to Edward Anderson.
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 - 15/12/04 Version 1.0b
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 Weakness of the pseudo-random matrix generator found for pro-
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 blem sizes being power of twos and larger  than 2^15;  Thanks
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 to Gregory Bauer. This problem has not been fixed. It is thus
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 currently recommended to  HPL  users willing to test matrices
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 of size larger than 2^15 to not use power twos.
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 When the matrix size is such that one needs  > 16 GB  per MPI
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 rank,  the  intermediate  calculation  (mat.ld+1) * mat.nq in
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 HPL_pdtest.c  ends up  overflowing  because  it is done using
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 32-bit arithmetic.  This issue has been fixed by  typecasting
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 to size_t; Thanks to John Baron.
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 - 09/10/08 Version 2.0
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 Piotr Luszczek changed to 64-bit RNG, modified files:
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 -- [M] include/hpl_matgen.h
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 -- [M] testing/matgen/HPL_ladd.c
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 -- [M] testing/matgen/HPL_lmul.c
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 -- [M] testing/matgen/HPL_rand.c
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 -- [M] testing/ptest/HPL_pdinfo.c
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 For a motivation for the change, see:
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    Dongarra and Langou, ``The Problem with the Linpack
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    Benchmark Matrix Generator'', LAWN 206, June 2008.
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 -- [M] testing/ptest/HPL_pdtest.c  --
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 Julien Langou changed the test for correctness from
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      ||Ax-b||_oo / ( eps * ||A||_1  * N            )
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      ||Ax-b||_oo / ( eps * ||A||_1  * ||x||_1      )
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      ||Ax-b||_oo / ( eps * ||A||_oo * ||x||_oo * N )
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 to the normwise backward error
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      || r ||_oo / ( eps * ( || x ||_oo * || A ||_oo + || b ||_oo ) * N )
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 See:
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  Nicholas J. Higham, ``Accuracy and Stability of Numerical Algorithms'',
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  Society for Industrial and Applied Mathematics, Philadelphia, PA, USA,
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  Second Edition, pages = xxx+680, ISBN = 0-89871-521-0, 2002.
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 Note that in our case || b ||_oo is almost for sure
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 1/2, we compute it anyway.
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