[ncl-talk] could i try dim_kde function before ncl 6.5 released

LI Qi liqi123sh at qq.com
Wed Jul 26 11:32:43 MDT 2017

Dear Dennis,

Thank you for your reply!
Yesterday I just googled "ncl kernel density estimation" and that page popped up. At that time Im so happy to find NCL also has this function  (means I don't need to learn R).
What's your said (hist_binwidth and invoking kde ) is exactly what I want.
But if it's very bother to invoke the funciton or it's need much time and energy in the develepment, then just ignore me. I can learn R for the moment.


------------------ Original ------------------
From:  "Dennis Shea";<shea at ucar.edu>;
Date:  Thu, Jul 27, 2017 00:42 AM
To:  "LI Qi"<liqi123sh at qq.com>; 
Cc:  "ncl-talk"<ncl-talk at ucar.edu>; 
Subject:  Re: [ncl-talk] could i try dim_kde function before ncl 6.5 released

Placing the 6.5.0 KDE function documentation onto the publicly available NCL URL was a mistake on my part. 
It was meant for NCL's internal draft documentation URL. I used

%> unw dim_kde.xml

instead of

%> unw -t dim_kde.xml


If you look at:

there is no mention of the 'dim_kde' function. Hence, 'dim_dke' is not yet in the development NCL 6.5.0. There is no time estimate of when it will be included.


An NCL script that invokes the KDE fortran subroutine via a shared object is available. It returns the PDF (ie: "smooth curve"). I can make this available. Let ncl-talk know if you want this. 

There is also an as-yet undocumented NCL language 'hist_binwidth'  that estimates optimal bin-widths using Silverman's rule-of-thumb for normal and quantile densities; and, uses the 'dim_kde' function. An NCL script that invokes the shared object is available for this also.


On Tue, Jul 25, 2017 at 2:23 PM, LI Qi <liqi123sh at qq.com> wrote:
Dear NCL,

Is there any way I can try the gaussian kernel density estimation (KDE) (https://www.ncl.ucar.edu/Document/Functions/Built-in/dim_kde.shtml) before next version released?
I have sample histograms and would like a smooth curve overlaid.

Thanks and best regards,

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