diff --git a/src/conf.py b/src/conf.py
index ee7fbe31a7..af920f8965 100644
--- a/src/conf.py
+++ b/src/conf.py
@@ -264,6 +264,7 @@
 
 # Additional stuff for the LaTeX preamble.
 latex_elements['preamble'] = '\\usepackage{amsmath}\n\\usepackage{amssymb}\n\\usepackage[retainorgcmds]{IEEEtrantools}\n\\usepackage{mathtools}\n'
+latex_additional_files = ['docs/sphinx/latex_macros.sty']
 
 bibtex_bibfiles = ['docs/sphinx/biblio_wave.bib']
 
@@ -271,13 +272,11 @@
 # add LaTeX macros
 
 f = open('docs/sphinx/latex_macros.sty')
-imgmath_latex_preamble = ""
+imgmath_latex_preamble = "\\usepackage{mathtools}"
 imgmath_image_format = 'svg'
 imgmath_font_size = 14
 
 for macro in f:
-    # used when building latex and pdf versions
-    latex_elements['preamble'] += macro + '\n'
     # used when building html version
     imgmath_latex_preamble += macro + '\n'