makeidx in middle of page

org-ref.org

#+latex_header: \usepackage{makeidx}
#+latex_header: \makeindex
# This ridiculousness is to make the index start in the middle of a page.
# https://tex.stackexchange.com/questions/23870/index-shouldnt-start-new-page
#+latex_header: \makeatletter
#+latex_header: \renewenvironment{theindex}
#+latex_header:                {\section*{\indexname}%
#+latex_header:                 \@mkboth{\MakeUppercase\indexname}%
#+latex_header:                         {\MakeUppercase\indexname}%
#+latex_header:                 \thispagestyle{plain}\parindent\z@
#+latex_header:                 \parskip\z@ \@plus .3\p@\relax
#+latex_header:                 \columnseprule \z@
#+latex_header:                 \columnsep 35\p@
#+latex_header:                 \let\item\@idxitem}
#+latex_header:                {}
#+latex_header: \makeatother