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Re: Re: ListCurvePathPlot

  • To: mathgroup at smc.vnet.net
  • Subject: [mg95996] Re: [mg95942] Re: ListCurvePathPlot
  • From: DrMajorBob <btreat1 at austin.rr.com>
  • Date: Sat, 31 Jan 2009 06:44:58 -0500 (EST)
  • References: <gls253$hq3$1@smc.vnet.net> <200901301045.FAA06534@smc.vnet.net>
  • Reply-to: drmajorbob at longhorns.com

This gives ONE path on some draws, two, three, or four on others, et  
cetera:

data = Table[
    RandomReal[{.8, 1.2}] {Cos[t], Sin[t]}, {t, 0, 2 \[Pi] - 2 \[Pi]/6,
      2 \[Pi]/32}];
ListCurvePathPlot[data, InterpolationOrder -> 2, Axes -> False,
  InterpolationOrder -> 16]

Sometimes if there's one path it's a closed path, sometimes it isn't...

Sigh... Still not sure what this accomplishes for us.

Bobby

On Fri, 30 Jan 2009 04:45:17 -0600, Jens-Peer Kuska  
<kuska at informatik.uni-leipzig.de> wrote:

> Hi,
>
> and more over, it does it wrong because I try your example with
>
> data = Table[
>     RandomReal[{.8, 1.2}] {Cos[t], Sin[t]}, {t, 0, 2 \[Pi] - 2 \[Pi]/6,
>       2 \[Pi]/32}];
>
> got the data
> data-{{0.899074, 0}, {0.931267, 0.185241}, {1.10439, 0.457454},  
> {0.955484,
>    0.638434}, {0.795648, 0.795648}, {0.547609, 0.819554}, {0.318697,
>    0.769402}, {0.232974, 1.17124}, {0, 1.18407}, {-0.207593,
>    1.04364}, {-0.459194, 1.10859}, {-0.639312, 0.956798}, {-0.664321,
>    0.664321}, {-0.953214, 0.636917}, {-0.966874, 0.400492}, {-0.893422,
>     0.177713}, {-1.02206,
>    0}, {-1.09618, -0.218044}, {-0.995037, -0.412158}, {-0.775199, \
> -0.517972}, {-0.722555, -0.722555}, {-0.643561, -0.963157}, \
> {-0.373253, -0.901112}, {-0.232702, -1.16987}, {0, -0.93512}, \
> {0.189465, -0.952506}, {0.338656, -0.817588}};
>
> and the result is
>
> ListCurvePathPlot[data, InterpolationOrder -> 3, Axes -> False,
>   InterpolationOrder -> 16]
>
> not curved, not interpolated  and broken into *two* pieces.
>
> May be you don't understand the function because it is buggy and useless  
> ...
>
> Regards
>    Jens
>
> David Park wrote:
>> I don't understand the new ListCurvePathPlot, which the Help page says:
>> "attempts to reconstruct smooth curves defined by the specified set of
>> points."
>>
>>
>>
>> This plot routine also has the option: InterpolationOrder. And the word
>> "Curve" appears not only in the name but repeatedly in the descriptions.
>> But look at the following example:
>>
>>
>>
>> data = Table[
>>
>>    RandomReal[{.8, 1.2}] {Cos[t], Sin[t]}, {t, 0, 2 \[Pi] - 2 \[Pi]/6,
>>
>>      2 \[Pi]/6}];
>>
>> ListCurvePathPlot[data,
>>
>>  InterpolationOrder -> 3,
>>
>>  Axes -> False]
>>
>>
>>
>> I don't see anything "smooth" or "curvy" about the results!  So it seems
>> that these terms are a misdirection in understanding the use of the  
>> routine.
>> It appears that what the routine actually does is reorder the points to  
>> give
>> some simpler line (not curve) than the original set of points. But what  
>> is
>> the criterion for this? Is this some well know computational geometry
>> algorithm? Was InterpolationOrder included as an option by mistake? Did  
>> the
>> implementation change from the original intention? What is the purpose  
>> of
>> the routine? What is the relation of this and the spline functions?
>>
>>
>>
>> David Park
>>
>> djmpark at comcast.net
>>
>>  <http://home.comcast.net/~djmpark> http://home.comcast.net/~djmpark/
>>
>



-- 
DrMajorBob at longhorns.com


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