为了加快处理速度pgfplots，据我了解，应该可以这样写
\usepackage{pgfplots}
\usepgfplotslibrary{external}
\tikzexternalize
\write18但是，我收到一个错误（Mactex 2016），似乎与系统调用等有关。我得到
! Package tikz Error: Sorry, the system call 'lualatex -halt-on-error -interact ion=batchmode -jobname "portoptreport1-figure0" "\def\tikzexternalrealjob{porto ptreport1}\input{portoptreport1}"' did NOT result in a usable output file 'port optreport1-figure0' (expected one of .pdf:.jpg:.jpeg:.png:). Please verify that you have enabled system calls. For pdflatex, this is 'pdflatex -shell-escape'. Sometimes it is also named 'write 18' or something like that. Or maybe the com mand simply failed? Error messages can be found in 'portoptreport1-figure0.log' . If you continue now, I'll try to typeset the picture.