[Numpy-discussion] Best way to handle "wrapped" array accesses?
Fri Oct 26 03:31:00 CDT 2007
I've seen a few references on this, but hadn't found a proper solution...
I'm doing Lattice-Boltzmann simulations with periodic boundary conditions,
which always necessarily involve either padding the edges and doing
additional steps, or making a "wrapped" array (for example, if I have an
array that's N rows by M columns, and cells are moving right, I then make
a "wrapped" array a la "D = hstack( A[:,0:-1], A[:,-1:] )" (creating a
temporary) and adding them.
I'd like to avoid the temporary and still make the operation as fast as
possible. A really elegant solution would be a "wrapped array" subclass
that would automatically handle the indexing (C = A[:,1:M+1] + B), but I'm
not certain how friendly the array class is with subclassing.
What's the best way to handle this? Am I pretty much stuck with
temporaries or hacked functions ("add_wrapped(A, offset, B, C)")?
(It's probably a moot point in the long term, as once things get big I
will have to use the cluster, which is probably not SciPy-friendly and
it'll likely be a bit before I can convince the sys admin to let me play
outside the "installed software" boundaries. But now I just want to
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