The multicol
environment is not designed to support column floats. The concept of balancing makes this next to impossible to automatically provide correct results in the general case and therefore I decided not to extend multicol
in this direction for 2e.
For example, with multicol
you can change the number of columns mid-page, how should that reflect on float placements, given that TeX can't re-break prargraphs so that they flow around floats that then not fit the column width any longer.
For the less general case, e.g., fixed 2-column layout with only a little bit of balancing, one could probably extend multicol
to support this, but it would then break in the more generic cases, and as I said it isn't there.
Update
Having said the above, I couldn't resist the challenge to implement at least a trivial implementation of this. The idea is simple: we offer a command that takes 3 arguments: a page number, a column number, and a float body, e.g.
\multicolfloat{1}{2}{\centering
\includegraphics{cat.eps}
\captionof{figure}{A test}
}
The above is using \captionof
from the caption
package as this isn't really a float so \caption
would complain unless it gets modified which I didn't do.
This command can be used inside a multicols
environment and asks for this float to be placed on top column 2 on page 1. So a lot of manual work if the amount of text is changing or the multicols
environment is moved. This could be done differently and better, but that is more than I had time for.
So here is the code and a test file, a mixture of patching some hooks into multicol
and implementing the new functionality as a LaTeX3 property list.
\begin{filecontents}{multicol-floats.sty}
% Author Frank Mittelbach, 2012, License LPPL
%
% Providing column floats for multicol (proto-type implementation)
%
% Document Interface:
%
% \multicolfloat <page-num> <col-num> <float-body>
%
% To be used inside a multicols environment.
% Can only place floats on full pages not balanced pages.
% Should probably be an environment but didn't do that this time around.
%
% Subject to change and ... No support :-)
\RequirePackage{etoolbox}
\RequirePackageWithOptions{multicol}
% Patching multicol to get a few hooks in as needed
\patchcmd{\multi@column@out}%
{\setbox\count@ \vsplit\@cclv to\dimen@}%
{\create@split@column \count@ \dimen@}%
{\typeout{*** SUCCESS ***}}{\typeout{*** FAIL ***}}
\patchcmd{\multi@column@out}
{\setbox\mult@rightbox \vsplit\@cclv to\dimen@}
{\create@split@column \mult@rightbox \dimen@}
{\typeout{*** SUCCESS ***}}{\typeout{*** FAIL ***}}
\patchcmd\endmulticols
{\output}{\mc@check@unset@floats\output}
{\typeout{*** SUCCESS ***}}{\typeout{*** FAIL ***}}
\newcount\mc@column
\patchcmd\process@cols
{\relax}{\relax\mc@column\@ne}
{\typeout{*** SUCCESS ***}}{\typeout{*** FAIL ***}}
\patchcmd\process@cols
{\advance}{\advance\mc@column\@ne\advance}
{\typeout{*** SUCCESS ***}}{\typeout{*** FAIL ***}}
% Implementation of new functionality
\RequirePackage{xparse}
\ExplSyntaxOn
\DeclareDocumentCommand \multicolfloat { m m m }
{
\mc_float:nnn {#1} {#2} {#3}
}
% Implementation
\cs_generate_variant:Nn \prop_gpop:NnNT { NxNT }
\cs_generate_variant:Nn \prop_get:NnNTF { NxNTF }
\prop_new:N \__g_mc_float_prop
\tl_new:N \__l_mc_float_tl
\cs_new:Npn \mc_float:nnn #1#2#3 {
% safe a float body under the property key "page,col"
% if there already exist a float, combine them
\prop_get:NxNTF \__g_mc_float_prop {#1,#2} \__l_mc_float_tl
{
\prop_gput:Nno \__g_mc_float_prop {#1,#2}
{\__l_mc_float_tl
\vskip \floatsep
\vbox{\hsize\columnwidth #3}
}
}
{
\prop_gput:Nnn \__g_mc_float_prop {#1,#2}
{\vbox{\hsize\columnwidth #3}}
}
}
\cs_new:Npn \create@split@column #1#2 {
% look up any saved floats for current page and current column and if they exist
% add them to the to the top of box 255 and then split off a column
\prop_gpop:NxNT \__g_mc_float_prop
{\thepage, \the\mc@column }
\__l_mc_float_tl
{
\vbox_set:Nn \c_two_hundred_fifty_five
{ \__l_mc_float_tl
\vskip \textfloatsep
\vbox_unpack_clear:N \c_two_hundred_fifty_five
}
}
\vbox_set_split_to_ht:NNn #1 \c_two_hundred_fifty_five {#2}
}
\cs_new:Npn \mc@check@unset@floats {
% if the property list is not empty we haven't typeset all floats for some reason
% give error message and a display of the property list content (crude ... but there you go)
\prop_if_empty:NF \__g_mc_float_prop
{ \PackageError{xmulticol}{Unset~ column~ floats,~ details~ below}
{ }
\prop_show:N \__g_mc_float_prop
\prop_gclear:N \__g_mc_float_prop
}
}
\ExplSyntaxOff
\end{filecontents}
\documentclass{article}
\usepackage{lipsum,caption,graphicx}
\usepackage{multicol-floats}
\begin{document}
\begin{multicols}{2}
\multicolfloat{1}{1}{TEST 1-1}
\multicolfloat{1}{2}{\centering
\includegraphics{cat.eps}
\captionof{figure}{A test}
}
\multicolfloat{1}{2}{TEST \captionof{figure}{Another test}}
\multicolfloat{2}{1}{TEST 2-1}
\lipsum %\lipsum
\end{multicols}
\end{document}
As a result one gets the following output on the first page with the three floats placed in column one and two:
With only one \lipsum
in the test file, the multicols
ends on the next page and thus the float for page 2 column one isn't typeset and we get the following error message as well:
! Package xmulticol Error: Unset column floats, details below.
See the xmulticol package documentation for explanation.
Type H <return> for immediate help.
...
l.136 \end{multicols}
?
The property list \__g_mc_float_prop contains the pairs (without outer
braces):
> {2,1} => {\vbox {\hsize \columnwidth TEST 2-1}}.
<recently read> }
l.136 \end{multicols}
Not really great :-) but then this is just a proto-type anyway. In fact, if a multicols
environment starts in the middle of a page then the float will appear on the top of the column of the multicol not at the top of the page. After all, the column sizes might differ, So that is rather a feature not a bug ... hey anything on this is a feature as I said totally unsupported in this shape --- enjoy nevertheless
Next paragraph appears in page 11 from IEEEtran_HOWTO
Another LATEX2ε
limitation (patched with stfloats or not) is that
double column floats will not appear on the same page where they are
defined. So, the user will have to define such things prior to the
page on which they are to (possibly) appear.
So if you want that your figure be placed where Conclusions and References, declare it in previous page. And remember that due to next paragraph (page 9)
Furthermore, IEEE journals never place floats in the first column of
the first page and rarely (if ever) do they do so in the second column
of the first page. Middle in-text placement (“here”) is not used.
you must test it with enough text to fill more than one page, otherwise your figure will always appear on an empty second page.
Best Answer
You're overcomplicating things. You don't need floats (
figure
) and\caption
. Adjust the definition of\problem
to suit.Note that I didn't load
graphicx
because I don't have your images. Load it and, of course, remove the bogus definition of\includegraphics
I added just for the example.