Re: Re: Combined Set, SetDelayed

*To*: mathgroup at smc.vnet.net*Subject*: [mg100906] Re: [mg100875] Re: Combined Set, SetDelayed*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Thu, 18 Jun 2009 04:50:55 -0400 (EDT)*References*: <h0vteh$6v2$1@smc.vnet.net> <h12gck$e8s$1@smc.vnet.net> <h19hur$oqf$1@smc.vnet.net> <200906170835.EAA08294@smc.vnet.net>

On 17 Jun 2009, at 17:35, Helen Read wrote: > magma wrote: >> Helen Read wrote: >>> AES wrote: >>>> Helen Read <h... at together.net> 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 > output. > > -- > Helen Read > University of Vermont > Chop[1.87003*10^-15] 0 and that's all there is to it... Andrzej Kozlowski

**References**:**Re: Combined Set, SetDelayed***From:*Helen Read <hpr@together.net>