今天我在 atom 中工作时，使用命令 \vec 时，箭头出现在文本的左上角。我以前从未遇到过这个问题，我的旧文件编译得很好。这是一个例子：
\documentclass[12pt,letterpaper]{article}
\usepackage{amsmath, amsfonts, enumerate, graphicx, siunitx, amsthm}
\setlength{\parindent}{0em}
\setlength{\parskip}{1em}
\begin{document}
$\vec{a}$
\end{document}
以下是日志文件：
This is pdfTeX, Version 3.141592653-2.6-1.40.23 (TeX Live 2021/W32TeX) (preloaded format=pdflatex 2021.9.11) 7 NOV 2021 16:05
entering extended mode
restricted \write18 enabled.
%&-line parsing enabled.
**"Question 1.tex"
(./Question 1.tex
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Package: amsmath 2021/04/20 v2.17j AMS math features
\@mathmargin=\skip49
For additional information on amsmath, use the `?' option.
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Package: amstext 2000/06/29 v2.01 AMS text
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LaTeX Font Info: Redeclaring font encoding OML on input line 743.
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LaTeX Info: Redefining \[ on input line 2923.
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Package: amsfonts 2013/01/14 v3.01 Basic AMSFonts support
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LaTeX Font Info: Redeclaring math symbol \hbar on input line 98.
LaTeX Font Info: Overwriting math alphabet `\mathfrak' in version `bold'
(Font) U/euf/m/n --> U/euf/b/n on input line 106.
)
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File: graphics.cfg 2016/06/04 v1.11 sample graphics configuration
)
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))
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)
(c:/texlive/2021/texmf-dist/tex/latex/siunitx/siunitx.sty
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\etb@tempcnta=\count269
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Package: pdftexcmds 2020-06-27 v0.33 Utility functions of pdfTeX for LuaTeX (HO
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)
Package color Info: Driver file: pdftex.def on input line 149.
)
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(c:/texlive/2021/texmf-dist/tex/latex/l3packages/l3keys2e/l3keys2e.sty
(c:/texlive/2021/texmf-dist/tex/latex/l3kernel/expl3.sty
Package: expl3 2021-08-27 L3 programming layer (loader)
(c:/texlive/2021/texmf-dist/tex/latex/l3backend/l3backend-pdftex.def
File: l3backend-pdftex.def 2021-08-04 L3 backend support: PDF output (pdfTeX)
\l__color_backend_stack_int=\count278
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))
Package: l3keys2e 2021-08-27 LaTeX2e option processing using LaTeX3 keys
)
(c:/texlive/2021/texmf-dist/tex/latex/tools/array.sty
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))
(c:/texlive/2021/texmf-dist/tex/latex/amscls/amsthm.sty
Package: amsthm 2020/05/29 v2.20.6
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)
Package translations Info: No language package found. I am going to use `englis
h' as default language. on input line 6.
(./Question 1.aux)
\openout1 = `"Question 1.aux"'.
LaTeX Font Info: Checking defaults for OML/cmm/m/it on input line 6.
LaTeX Font Info: ... okay on input line 6.
LaTeX Font Info: Checking defaults for OMS/cmsy/m/n on input line 6.
LaTeX Font Info: ... okay on input line 6.
LaTeX Font Info: Checking defaults for OT1/cmr/m/n on input line 6.
LaTeX Font Info: ... okay on input line 6.
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LaTeX Font Info: ... okay on input line 6.
LaTeX Font Info: Checking defaults for TS1/cmr/m/n on input line 6.
LaTeX Font Info: ... okay on input line 6.
LaTeX Font Info: Checking defaults for OMX/cmex/m/n on input line 6.
LaTeX Font Info: ... okay on input line 6.
LaTeX Font Info: Checking defaults for U/cmr/m/n on input line 6.
LaTeX Font Info: ... okay on input line 6.
(c:/texlive/2021/texmf-dist/tex/context/base/mkii/supp-pdf.mkii
[Loading MPS to PDF converter (version 2006.09.02).]
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) (c:/texlive/2021/texmf-dist/tex/latex/epstopdf-pkg/epstopdf-base.sty
Package: epstopdf-base 2020-01-24 v2.11 Base part for package epstopdf
Package epstopdf-base Info: Redefining graphics rule for `.eps' on input line 4
85.
(c:/texlive/2021/texmf-dist/tex/latex/latexconfig/epstopdf-sys.cfg
File: epstopdf-sys.cfg 2010/07/13 v1.3 Configuration of (r)epstopdf for TeX Liv
e
))
(c:/texlive/2021/texmf-dist/tex/latex/translations/translations-basic-dictionar
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File: translations-basic-dictionary-english.trsl (english translation file `tra
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)
Package translations Info: loading dictionary `translations-basic-dictionary' f
or `english'. on input line 6.
LaTeX Font Info: Trying to load font information for U+msa on input line 10.
(c:/texlive/2021/texmf-dist/tex/latex/amsfonts/umsa.fd
File: umsa.fd 2013/01/14 v3.01 AMS symbols A
)
LaTeX Font Info: Trying to load font information for U+msb on input line 10.
(c:/texlive/2021/texmf-dist/tex/latex/amsfonts/umsb.fd
File: umsb.fd 2013/01/14 v3.01 AMS symbols B
) [1
{c:/texlive/2021/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] (./Question 1.a
ux) )
Here is how much of TeX's memory you used:
6123 strings out of 478599
141779 string characters out of 5858101
413092 words of memory out of 5000000
23960 multiletter control sequences out of 15000+600000
409286 words of font info for 49 fonts, out of 8000000 for 9000
1141 hyphenation exceptions out of 8191
73i,5n,81p,402b,513s stack positions out of 5000i,500n,10000p,200000b,80000s
<c:/texlive/2021/texmf-dist/fonts/type1/public/amsfonts/cm/cmbx12.pfb><c:/
texlive/2021/texmf-dist/fonts/type1/public/amsfonts/cm/cmmi12.pfb><c:/texlive/2
021/texmf-dist/fonts/type1/public/amsfonts/cm/cmmi8.pfb><c:/texlive/2021/texmf-
dist/fonts/type1/public/amsfonts/cm/cmr12.pfb><c:/texlive/2021/texmf-dist/fonts
/type1/public/amsfonts/cm/cmr8.pfb>
Output written on "Question 1.pdf" (1 page, 53766 bytes).
PDF statistics:
33 PDF objects out of 1000 (max. 8388607)
19 compressed objects within 1 object stream
0 named destinations out of 1000 (max. 500000)
1 words of extra memory for PDF output out of 10000 (max. 10000000)