Display a figure over 2 columns in a 2 column layout on a fixed position

Question

I would like to display a figure in a 2 column document, though the figure has to appear over the 2 columns on a fixed position. I tried this:

\begin{figure*}[H]
 \begin{center}
 \includegraphics[scale=0.5]{features.JPG}
 \caption{Comparison of the classification algorithms with different feature space sizes}
 \label{features}
 \end{center}
\end{figure*}

But it does not work. Nothing really works when changing the H to h or ht etc ...

Anyone know the solution to this problem ?

Answer 1

based on an interchange of comments, i infer that this figure* is wanted somewhere other than at the top of a page.

see lamport, p.197, section c.9.1: h and b are "not possible for double-column figures or tables in two-column format."

some other approaches have been developed that you might find useful, for example as presented in this question: One column equation in twocolumn document class.