[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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