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MathGroup Archive 2005

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Re: Re: Maxima & Minima

  • To: mathgroup at smc.vnet.net
  • Subject: [mg53777] Re: [mg53758] Re: Maxima & Minima
  • From: DrBob <drbob at bigfoot.com>
  • Date: Thu, 27 Jan 2005 05:41:14 -0500 (EST)
  • References: <200501240837.DAA28176@smc.vnet.net><ct56fb$eak$1@smc.vnet.net> <200501260937.EAA00242@smc.vnet.net>
  • Reply-to: drbob at bigfoot.com
  • Sender: owner-wri-mathgroup at wolfram.com

Very nice!

(But we don't really know if the glitches ARE glitches, of course.)

Bobby

On Wed, 26 Jan 2005 04:37:09 -0500 (EST), Ray Koopman <koopman at sfu.ca> wrote:

> DrBob wrote:
>> Here's a complete list of local extrema in the raw data:
>>
>> data[[1+Flatten@Position[Partition[data[[All, 2]], 3, 1],
>>      {a_, b_, c_} /; b < Min[a, c] || b > Max[a, c]]]]
>>
>> {{0.51, 1.30244},
>>    {0.53, 1.3059},
>>    {0.54, 1.30544},
>>    {0.58, 1.31146},
>>    {0.59, 1.31105},
>>    {0.66, 1.32175},
>>    {0.67, 1.32041},
>>    {0.83, 1.81008},
>>    {1.11, 0.0324386},
>>    {1.71, 1.72145}}
>>
>> (Too many, if we assume the data is only approximate.)
>
> That approach works fine (at least with this data) if we widen the
> window and look more than one point to the left and right:
>
> With[{k = 2},
> data[[k + Flatten@Position[Partition[data[[All,2]],2k+1,1], x_List /;
> x[[k+1]] < Min[Delete[x,k+1]] || x[[k+1]] > Max[Delete[x,k+1]]]]]]
>
> will ignore the glitches and give
> {{0.83,1.81008},{1.11,0.0324386},{1.71,1.72145}}
>
>
>
>



-- 
DrBob at bigfoot.com
www.eclecticdreams.net


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