[Numpy-discussion] where are the benefits of ldexp and/or "array times 2"?

Robert Kern robert.kern@gmail....
Thu May 21 10:46:12 CDT 2009


On Thu, May 21, 2009 at 10:26, dmitrey <dmitrey.kroshko@scipy.org> wrote:
> Hi all,
> I expected to have some speedup via using ldexp or multiplying an
> array by a power of 2 (doesn't it have to perform a simple shift of
> mantissa?),

Addition of the exponent, not shift of the mantissa.

> but I don't see the one.

I said there *might* be a speedup, but it was probably going to be
insignificant. The overhead of using frexp and ldexp probably
outweighs any benefits.

-- 
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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