Read Me

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README                                             boxmg4wrf (2015/04/30)
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   (Parallel) Black Box Multigrid for (2D and 3D) Symmetric Problems

     This package contains an MPI-based parallel version of the robust
  Black Box Multigrid (BoxMG) algorithm that is largely based on the
  evolving serial version (currently 1.6.4).  Specifically, it is a
  parallel implementation of the BoxMG algorithm for symmetric 2D
  problems described in [1], and for symmetric 3D problems described
  in [3].  At this point it does not support the periodic or
  indefinite case, which is discussed in [2], nor does it include
  plane relaxation. Both of these features will be added in the near
  future.

      In two dimensions the code is suitable for discretizations of
  elliptic PDEs on a structured (logically rectangular) grids with up
  to 9 points in the stencil.  Similarly in three dimensions the code
  is suitable for discretizations of elliptic PDEs on structured
  (logically hexahedral) grids with up to 27 points in the stencil.
  Boundary conditions may be Dirichlet, Neumann or Robin, provided
  that the underlying matrix is symmetric positive definite.  The user
  is only required to provide the fine-grid stencil, the discrete
  right hand side, and an initial guess.  The code generates all
  coarse-grid and intergrid transfer operators. We note that is
  possible to treat both vertex- and cell-based discretizations
  provided the underlying structure is consistent with a logically
  rectangular or hexahedral grid.

     There should be very little trouble in porting BoxMG to different
  platforms.  The current configuration has been tested on Linux/Intel
  Linux/Alpha, Tru64(OSF1)/Alpha, and IRIX/R10K.

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 Feedback:
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This version is not actively supported, but you can try sending email to graupel@users.sf.net, who will try to answer as time allows.

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 References:
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  [1] J. E. Dendy, Jr., "Black Box Multigrid", J. Comput. Phys.,
      48, 366, (1982).

  [2] J. E. Dendy, Jr., "Black Box Multigrid for Periodic and 
      Singular Problems", Appl. Math. and Comput., 23, 1, (1988).

  [3] J. E. Dendy, Jr., "Two Multigrid Methods for Three-Dimensional
      Problems with Discontinuous and Anisotropic Coefficients", 
      SIAM J. Sci. Stat. Comp., Vol. 8, No. 2, pp. 673-685, (1987).

  [4] Put in the highlight

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 History, Contributions, and Collaborations:
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  The README for the serial version is included in extras/boxmg,
  and includes comments about the History of the serial code.
  As noted there Joel Dendy wrote the vast majority of the 
  original "legacy" code, and most of these core computational
  elements are preserved here.  The refactoring and recent development
  (1999-2004) was done by David Moulton, Markus Berndt, Joel Dendy, 
  and Travis Austin.  The code has been used by a growing number of 
  our collaborators, including Scott MacLachlan and Dhavide Aruliah, 
  who also kindly reported a bug, or three.  We hope more people will 
  find it useful in the future.  If there are features you need let us 
  know, it may be possible to add them. 

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 NonSymmetric BoxMG:
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  As noted in the README of the serial version, if there is sufficient
  interest, refactoring a nonsymmetric version of the BoxMG code would
  be possible.  So feel free to contact us if you would find this useful.

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