a | b

(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/TeX.pool.ltxml...
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/eTeX.pool.ltxml... 0.01 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/pdfTeX.pool.ltxml... 0.01 sec) 0.41 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/LaTeX.pool.ltxml... 0.41 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/article.cls.ltxml... 0.05 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/amsmath.sty.ltxml...
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/amsbsy.sty.ltxml... 0.00 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/amstext.sty.ltxml... 0.00 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/amsopn.sty.ltxml... 0.01 sec) 0.15 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/amsthm.sty.ltxml... 0.01 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/amssymb.sty.ltxml...
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/amsfonts.sty.ltxml... 0.01 sec) 0.07 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/eucal.sty.ltxml... 0.00 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/xcolor.sty.ltxml...
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/color.sty.ltxml... 0.04 sec)
(Processing definitions /usr/share/texlive/texmf-dist/tex/latex/graphics/dvipsnam.def... 0.18 sec) 1.47 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/url.sty.ltxml... 0.01 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/hyperref.sty.ltxml...
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/nameref.sty.ltxml... 0.00 sec) 0.08 sec)
(Loading /usr/local/share/perl/5.18.2/LaTeXML/Package/latexml.sty.ltxml... 0.02 sec)
(Loading /home/DRMF/DLMFmath.sty.ltxml...
Info:deprecated:ligature Old style arguments to DefMathLigature; please update
	/home/DRMF/DLMFmath.sty.ltxml line 360

(Loading /home/DRMF/DLMFfcns.sty.ltxml...
(Processing definitions /home/DRMF/DLMFfcns.sty... 1.67 sec) 1.70 sec)
(Loading /home/DRMF/DRMFfcns.sty.ltxml...
(Processing definitions /home/DRMF/DRMFfcns.sty... 0.73 sec) 0.76 sec) 2.60 sec)

ltxpsgi (LaTeXML version 0.8.2; revision 644644a)
processing started Sun Mar 5 13:18:11 2017

(Digesting TeX Anonymous String...
(Processing content Literal String \\ensuremat...
(Processing content Literal String {\\displays...
(Processing content Literal String \\begin{doc... 0.00 sec) 0.00 sec) 0.00 sec) 0.01 sec)
(Building...
(Loading compiled schema /usr/local/share/perl/5.18.2/LaTeXML/resources/RelaxNG/LaTeXML.model... 0.02 sec). 0.15 sec)
(Rewriting... 0.00 sec)
(Math Parsing...1 formulae ...
Warning:not_parsed:UNKNOWN>VERTBAR MathParser failed to match rule \'Anything\'
	at Literal String {\\displays; line 1 col 1
	In \"\\({\\displaystyle{\\displaystyle a|b}}\\)\"
	a[[UNKNOWN]]
	 > |[[VERTBAR]] b[[UNKNOWN]]
[F1]
Math parsing succeeded:
 ltx:XMath: 0/1
Symbols assumed as simple identifiers (with # of occurences):
 \'a{italic}\' (3), \'b{italic}\' (2)
Set MATHPARSER_SPECULATE to speculate on possible notations.
 0.02 sec)
(Finalizing... 0.00 sec)
Conversion complete: 1 warning.

(post-processing...
(Scan processing... 0.00 sec)
(CrossRef processing... 0.00 sec)
(MathML::Presentation[w/MathML::Content+TeXMath] processing...
Fatal:perl:die Perl died
	Can\'t locate object method \"getAttribute\" via package \"XML::LibXML::Document\" at /usr/local/share/perl/5.18.2/LaTeXML/Post.pm line 557.
	In Post::MathML::Presentation[@0x7fef4df... ->addCrossrefs
1 fatal error

Post-processing complete: 1 fatal error
processing finished Sun Mar 5 13:18:12 2017