snbinom

First derivatives of NB2 PMF used in <code>fitNB2</code>. Code is
taken from the function <code>snbinom()</code> in the <code>countreg</code> package
version 0.2-1 (2023-06-13) countregWALS.

Implements Weighted-Average Least Squares model averaging
for negative binomial regression models of Huynh (2024) <doi:10.48550/arXiv.2404.11324>,
generalized linear models of De Luca, Magnus, Peracchi (2018)
<doi:10.1016/j.jeconom.2017.12.007> and linear regression models of
Magnus, Powell, Pruefer (2010) <doi:10.1016/j.jeconom.2009.07.004>, see also
Magnus, De Luca (2016) <doi:10.1111/joes.12094>. Weighted-Average Least Squares
for the linear regression model is based on the original 'MATLAB' code by
Magnus and De Luca <https://www.janmagnus.nl/items/WALS.pdf>, see also
Kumar, Magnus (2013) <doi:10.1007/s13571-013-0060-9> and
De Luca, Magnus (2011) <doi:10.1177/1536867X1201100402>.

Kevin Huynh

WALS

Weighted-Average Least Squares Model Averaging

snbinom function

<dl><dt>x</dt>
<dd>Vector of quantiles.</dd>
<dt>mu</dt>
<dd>Vector of means.</dd>
<dt>size</dt>
<dd>Vector of dispersion parameter. If a scalar is given, the value
is recycled.</dd>
<dt>parameter</dt>
<dd>Specifies which parameter the derivative is taken for.
<code>parameter = c("mu", "size")</code> returns a matrix with derivatives
for both parameters.</dd>
<dt>drop</dt>
<dd>If <code>TRUE</code>, drops empty dimensions of return using
<code><a href="/link/drop?package=WALS&version=0.2.5" data-mini-rdoc="WALS::drop">drop</a></code>. If <code>FALSE</code> does not apply <code><a href="/link/drop?package=WALS&version=0.2.5" data-mini-rdoc="WALS::drop">drop</a></code>.</dd></dl>

Arguments

Internal function: first derivatives of NB2 PMF — snbinom

<dl>

<dt>x</dt>
<dd>Vector of quantiles.</dd>


<dt>mu</dt>
<dd>Vector of means.</dd>


<dt>size</dt>
<dd>Vector of dispersion parameter. If a scalar is given, the value
is recycled.</dd>


<dt>parameter</dt>
<dd>Specifies which parameter the derivative is taken for.
<code>parameter = c("mu", "size")</code> returns a matrix with derivatives
for both parameters.</dd>


<dt>drop</dt>
<dd>If <code>TRUE</code>, drops empty dimensions of return using
<code><a href='https://rdrr.io/r/base/drop.html'>drop</a></code>. If <code>FALSE</code> does not apply <code><a href='https://rdrr.io/r/base/drop.html'>drop</a></code>.</dd>

</dl>

snbinom: Internal function: first derivatives of NB2 PMF

Description

Usage

Value

Arguments

References