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Re: Combined Set, SetDelayed

  • To: mathgroup at
  • Subject: [mg100875] Re: Combined Set, SetDelayed
  • From: Helen Read <hpr at>
  • Date: Wed, 17 Jun 2009 04:35:54 -0400 (EDT)
  • References: <h0vteh$6v2$> <h12gck$e8s$> <h19hur$oqf$>
  • Reply-to: HPR <read at>

magma wrote:
> Helen Read wrote:
>> AES wrote:
>>> Helen Read <h... at> wrote:
>>>> 0.811 seconds. The second version, using the function that remembers
>>>> values, took only 1.87003*10^-15 seconds.
>>> The frequency of visible light is around 3*10^14 Hz, so that's around
>>> one period of a visible light wave.  Is there maybe a typo here?
>> No, no typo. Not sure what your point is.
> I think AES point is that this timing figure seems a bit too unrealistic.
> I personally got a timing of 1.33357*10^-17 sec. About 100 times faster!
> Now, a light signal - regardless of frequency - travels a distance of
> about 40 angstrom during that time.
> Is this meaningful or is it just a way for Mathematica to say that the
> operation was too fast to be timed properly?

Fair enough, but it wasn't a typo. I was merely reporting Mathematica's 

Helen Read
University of Vermont

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