Hi Ryan

Thanks for your answer.
Hi partially understood your suggestion.
This is due to my poor knowledge of the math behind.

In the mathlab script I'm trying to  convert
Vector is  3000  element (1x3000)
With values between -1 and 1
Pts is a 200 vector(200X1)

From matlab documentation the result should be  200 pair of values (one for 
each element in pts)
So, what is not clear is how I should consider vector.
For each value in pts which values must be considered from vector?

Hope you can help on that

Angelo
 

-----Original Message-----
From: Ryan Curtin [mailto:r...@ratml.org] 
Sent: martedì 13 febbraio 2018 15:16
To: Angelo DI SENA <angelo.dis...@st.com>
Cc: mlpack@lists.mlpack.org
Subject: Re: [mlpack] Implementation of matlab ksdensity function

On Tue, Feb 13, 2018 at 01:30:42PM +0000, Angelo DI SENA wrote:
> Hi
> 
> I'm trying to "translate" a complex matlab script in C++ using armadillo.
> I implemented some functions that are not present in armadillo, but 
> I'm currently blocked with ksdensity In particular I need to use 
> ksdensity with the following parameters
> 
> [ky kx] = ksdensity(vector,pts,'function','cdf');
> 
> for probability density estimate.
> 
> Is there any implementation of such function using mlpack/armadillo?

Hi Angelo,

It has been a long-standing open issue to implement fast tree-based kernel 
density estimation: https://github.com/mlpack/mlpack/issues/150
But unfortunately there is no implementation available today.

However, if you are just looking for something simple (if vector or pts is not 
too big), you can write a loop over all of the points in 'pts' to calculate the 
normal distribution value.  There may be a little bit of complexity 
involved---I don't know if ksdensity() does auto-tuning of the bandwidth to be 
used, etc. (I have not used it before).

One class that may help in mlpack is the GaussianDistribution class in 
src/mlpack/core/dists/gaussian_distribution.hpp.

I hope this helps; let me know if I can clarify anything.

Thanks!

Ryan

-- 
Ryan Curtin    | "Oh man, I shot Marvin in the face."
r...@ratml.org |   - Vincent
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