[ncl-talk] A useful tidbit about kmean clustering

[Barry Lynn]

Just to be clear: I am providing this information/code for interested users.

If anyone knows better how to specify the number of clusters, I would be
glad to hear.

Or, if anyone knows how to track their movement, as well.

Thank you.

On Wed, Jan 22, 2020 at 5:10 PM Barry Lynn <barry.h.lynn at gmail.com> wrote:

> Hi:
>
> I had a couple of problems running the code.
>
> 1) It is not obvious how to set the k_clst (how many cluster), especially
> when running from a script.
>
> 2) I really wanted to see the members of each cluster.
>
> Here, I do the following (in the Excerpt):
>
> 1) Set the number of clusters to 1 less than the number of points.
> Otherwise, the program produces zeros or undefined numbers. or just strange
> answers.
> 2) I then reduce the number of clusters until I have just a  cluster with
> 1 grid point, inclusive (or the minimum number of points).
> 3) Because I didn't know how to modify the call to the clustering program,
> I created my own from the fortran file, which outputs the members of each
> cluster.
> 4) I use WRAPIT it to call this program
>
> I have attached a self-contained fortran version of the code.
>
> Barry
>
>
>
> On Sun, Jan 19, 2020 at 5:30 PM Barry Lynn <barry.h.lynn at gmail.com> wrote:
>
>> Hi:
>>
>> Thank you for asking.
>>
>> I found the FORTRAN code and may pass on my modifications if warranted.
>>
>> Thanks
>>
>> On Sun, 19 Jan 2020 at 17:26 Dennis Shea <shea at ucar.edu> wrote:
>>
>>> I am not sure of the question.
>>> ---
>>> You would have to access the changed code via a 'shared object'
>>>
>>> Does it require additional arguments? The NCL version of 'kmns' uses
>>> double precision arguments.
>>>
>>> C NCLFORTSTART
>>>       subroutine *kmns136* (dat, m, n, clcntr, k,  ic1, nc
>>>      +                   ,iter, iseed, wss, ier)
>>>       implicit none
>>> c                            ! INPUT
>>>       integer m, n, k, iter, iseed
>>>       double precision dat(m,n)
>>> c                            ! INPUT/OUTPUT
>>>       integer ic1(m), nc(k), ier
>>>       double precision clcntr(n,k), wss(k)
>>> C NCLEND
>>> c                            ! LOCAL WORK ARRAYS
>>>       integer          ic2(m), ncp(k), itran(k), live(k)
>>>       double precision an1(k), an2(k), d(m)
>>>       integer nv, kk, mm
>>> ====
>>>
>>> Change: * kmns136* to (say) kmns136x
>>>
>>> Then use WRAPIT to generate the shared object
>>>
>>>
>>>
>>>
>>>
>>> On Sun, Jan 19, 2020 at 4:04 AM Barry Lynn via ncl-talk <
>>> ncl-talk at ucar.edu> wrote:
>>>
>>>> Hello:
>>>>
>>>> I would like to use cluster analysis and it would be very helpful (I
>>>> hope) if I could modify the source code.
>>>>
>>>> I downloaded the NCL source code from here:
>>>>
>>>> https://www.earthsystemgrid.org/dataset/ncl.640.src/file.html
>>>>
>>>> and found the Fortran (.f) programs in this directory.
>>>>
>>>> NCL_SOURCE/ncl_ncarg-6.4.0/ni/src/lib/nfpfort
>>>>
>>>> Barry
>>>> --
>>>> Barry H. Lynn, Ph.D
>>>> Senior Associate Scientist, Lecturer,
>>>> The Institute of the Earth Science,
>>>> The Hebrew University of Jerusalem,
>>>> Givat Ram, Jerusalem 91904, Israel
>>>> Tel: 972 547 231 170
>>>> Fax: (972)-25662581
>>>>
>>>> C.E.O, Weather It Is, LTD
>>>> Weather and Climate Focus
>>>> http://weather-it-is.com
>>>> Jerusalem, Israel
>>>> Local: 02 930 9525
>>>> Cell: 054 7 231 170
>>>> Int-IS: x972 2 930 9525
>>>>
>>>> _______________________________________________
>>>> ncl-talk mailing list
>>>> ncl-talk at ucar.edu
>>>> List instructions, subscriber options, unsubscribe:
>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>
>>> --
>> Barry H. Lynn, Ph.D
>> Senior Associate Scientist, Lecturer,
>> The Institute of the Earth Science,
>> The Hebrew University of Jerusalem,
>> Givat Ram, Jerusalem 91904, Israel
>> Tel: 972 547 231 170
>> Fax: (972)-25662581
>>
>> C.E.O, Weather It Is, LTD
>> Weather and Climate Focus
>> http://weather-it-is.com
>> Jerusalem, Israel
>> Local: 02 930 9525
>> Cell: 054 7 231 170
>> Int-IS: x972 2 930 9525
>>
>>
>
> --
> Barry H. Lynn, Ph.D
> Senior Associate Scientist, Lecturer,
> The Institute of the Earth Science,
> The Hebrew University of Jerusalem,
> Givat Ram, Jerusalem 91904, Israel
> Tel: 972 547 231 170
> Fax: (972)-25662581
>
> C.E.O, Weather It Is, LTD
> Weather and Climate Focus
> http://weather-it-is.com
> Jerusalem, Israel
> Local: 02 930 9525
> Cell: 054 7 231 170
> Int-IS: x972 2 930 9525
>
>

-- 
Barry H. Lynn, Ph.D
Senior Associate Scientist, Lecturer,
The Institute of the Earth Science,
The Hebrew University of Jerusalem,
Givat Ram, Jerusalem 91904, Israel
Tel: 972 547 231 170
Fax: (972)-25662581

C.E.O, Weather It Is, LTD
Weather and Climate Focus
http://weather-it-is.com
Jerusalem, Israel
Local: 02 930 9525
Cell: 054 7 231 170
Int-IS: x972 2 930 9525
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20200122/4350b199/attachment.html>