When you tried using Arrays, I presume you used an array indexed by a
pair (i,j), and just reversed the order of the index pair to switch from
row-wise to column-wise access? It's hard to see how that would slow you
down. Perhaps the slowdown was caused by excessive array copying?
the difference can be in locality wrt the memory hierarchy: is the next element
nearby most of the time (apart from array borders), or a row-/column-width
away most of the time?
i understand that, eg, fortran and c differ in their default interpretations of array
layout, so naively translated benchmarks might suffer from running against the
grain in one of the two (row-major loops over a column-major layout, or the
other way round).
claus
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