## table of contents

GBKER(1) | User Commands | GBKER(1) |

# NAME¶

gbker - Produce kernel density estimation

# SYNOPSIS¶

**gbker** [*options*]

# DESCRIPTION¶

Compute the kernel density estimation on an equispaced grid. Data
are read from standard input. The kernel bandwidth, if not provided with the
option **-H**, is set automatically using simple heuristics. Normally the
whole support is displayed. The option **-w** can be used to restrict the
computation to specific range of values. The method used to compute the
density is set by the option **-M**. The boundaries of the grid are
slightly different in the different cases.

# OPTIONS¶

**-n**- number of equispaced points/bins where the density is computed (default 64)
**-w**- set the grid boundaries with min,max (default whole support)
**-H**- set the kernel bandwidth
**-S**- scale the automatic kernel bandwidth
**-K**- choose the kernel to use (default 0)
- 0
- Epanenchnikov
- 1
- Rectangular
- 2
- Gaussian
- 3
- Laplacian
**-M**- choose the method for density computation (default 0)
- 0
- use FFT (# grid points rounded to nearest power of 2)
- 1
- use discrete convolution (compact kernels only; bins>2)
- 2
- explicit summation (boundaries excluded)
**-F**- specify the input fields separators (default " \t")

# EXAMPLES¶

- gbker -n 128 -K 2 < file
- use a Gaussian kernel to compute the density on 128 equispaced points with the FFT approach. All the data in 'file' are used, multiple columns are pooled.
- gbker -K 3 -M 2 < file
- use a Laplacian kernel to compute the density on 64 points. The method used is the explicit summation.

# AUTHOR¶

Written by Giulio Bottazzi

# REPORTING BUGS¶

Report bugs to <gbutils@googlegroups.com>

Package home page <http://cafim.sssup.it/~giulio/software/gbutils/index.html>

# COPYRIGHT¶

Copyright © 2001-2018 Giulio Bottazzi This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License (version 2) as published by the Free Software Foundation;

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

October 2018 | gbker 6.0.beta2 |