... explicitly 1
  In our prototype implementation we provide sample scatter/gather routines.

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... domain 2
  This is the normal situation when the pattern of the sparse matrix is symmetric, which is equivalent to say that the interaction between two variables is reciprocal. If the matrix pattern is non-symmetric we may have one-way interactions, and these could cause a situation in which a boundary point is not a halo point for its neighbour.

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... follows 3
  The string is case-insensitive

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