[Tex/LaTex] Symbol for relative entropy

symbols

Could you help me with typesetting the following symbol (marked by red frame):

I searched over all possible manuals but was not able to find it. It looks like capital D, but actually it is not the same.

It looks to me like a constructed symbol (and even if it is a font, it may be easier to construct the symbol than find the font). For example:

enter image description here

\documentclass{article}


\begin{document}


$I\mkern-8muD((p,1-p)$

\end{document}

Note that the document uses Springer's LNCS style. In this style, all Greek letters are in italics, and vectors are denoted by boldface.

Most likely the bold italic Delta is produced in this particular case by something similar to this:

\documentclass{llncs}
\begin{document}
$\vec{\Delta}$
\end{document}

The result is:

llncs

Note that if you used the article class, the same code would produce a normal Delta with an arrow:

article

This is a clear case for \accentset from the accents package:

output

\documentclass{article}
\usepackage{accents}
\newcommand{\vect}[1]{\accentset{\rightharpoonup}{#1}}
\begin{document}
$\vect{x}$
\end{document}