[Numpy-discussion] ANN: MaskedArray as a subclass of ndarray?-?followup
Robert Kern
robert.kern at gmail.com
Fri Jan 19 14:00:44 EST 2007
Stefan van der Walt wrote:
> A "nice C level api" sounds like the definition of oxymoron :) Why
> would we argue for more C than absolutely necessary in a Python-based
> library?
Well, it's more often absolutely necessary than you might think. Any common
operation on the array should be written in C to avoid the Python function call
overhead. We learned that with recarrays. The a.column_name notation (equivalent
to a['column_name']) in implemented in a Python method __getattribute__. If you
happen to use this in a tight loop, you'll find that __getattribute__ is a
bottleneck.
Unfortunately, the methods you might want to add or override on an ndarray
subclass are going to be the ones that you would want to be efficient.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
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