TeX memory size error when using TikZ foreach children in trees

Question

Nearly Identical: How to expand TeX's “main memory size”? (pgfplots memory overload)

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I'm getting the same error as the other question, but the answer there is not handling my issue. I believe the error from the other question was due to using many images in the same file; my error is due (I think) to having a lot of memory usage in one image alone. Thus, the externalizing solution doesn't seem to be working.

I'm trying to generate a tree diagram for a paper I'm writing. It involves the exponential growth of nodes by 3's up to 3^8 = 6,561 for a total of ~9,000 total nodes.

Here is the code:

\documentclass[11pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{tikz}
\usetikzlibrary{shapes,trees}
\usetikzlibrary{external}
\tikzexternalize

\begin{document}

\begin{tikzpicture}
[grow cyclic,
level 1/.style={level distance=30mm,sibling angle=120},
level 2/.style={level distance=30mm,sibling angle=60},
level 3/.style={level distance=10mm,sibling angle=50},
level 4/.style={level distance=6mm,sibling angle=30},
level 5/.style={level distance=4mm,sibling angle=10},
level 6/.style={level distance=2mm,sibling angle=7},
level 7/.style={level distance=2mm,sibling angle=7},
every node/.style={circle,draw,inner sep=1.5pt},
dot/.style={circle,fill,inner sep=0.5pt}]
\node {\tiny{you!}}
  child foreach \x in {1,2,3} {node[dot] {}
 {child foreach \x in {1,2,3} {node[dot] {}
 {child foreach \x in {1,2,3} {node[dot] {}
 {child foreach \x in {1,2,3} {node[dot] {}
 {child foreach \x in {1,2,3} {node[dot] {}
 {child foreach \x in {1,2,3} {node[dot] {}
 {child foreach \x in {1,2,3} {node[dot] {}}}}}}}}}}}}}};

\end{tikzpicture}

\end{document}

I've tried calling this via pdflatex -shell-escape file, but it seems that the last iteration is what kills it. It generates fine if I just remove one of the iterative steps. In other words, 3^6 nodes works, but not 3^7. I'm actually trying to go to 3^8.

Any suggestions?

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Here is the exact error while running pdflatex -shell-escape file that halts:

! Package tikz Error: Sorry, the system call 'pdflatex -shell-escape -halt-on-e
rror -interaction=batchmode -jobname "test-figure0" "\def\tikzexternalrealjob{t
est}\input{test}"' did NOT result in a usable output file 'test-figure0' (expec
ted one of .pdf:.jpg:.jpeg:.png:). Please verify that you have enabled system c
alls. For pdflatex, this is 'pdflatex -shell-escape'. Sometimes it is also name
d 'write 18' or something like that. Or maybe the command simply failed? Error 
messages can be found in 'test-figure0.log'. If you continue now, I'll try to t
ypeset the picture.

Again, running with just one less level compiles fine (without -shell-escape or externalization), so I don't think this message is indicating that anything is wrong with my code, but I could be wrong.

Answer 1

If you compile the code without externalization, pdflatex indeed complains about exceeded memory size. A simple solution is to compile with lualatex instead of pdflatex, which doesn't seem to have a memory size limitation (or at least one that is sufficiently high). 8 levels works flawlessly with LuaLaTeX (though it did take some time to compile).

For externalization, you need to tell TikZ to use LuaLaTex:

\tikzset{external/system call={lualatex \tikzexternalcheckshellescape -halt-on-error
-interaction=batchmode -jobname "\image" "\texsource"}}

Answer 2

Thanks to @Caramdir for the suggestion, but even with externalization I'm blowing the memory. I think from what I've read, externalization works if there are many smaller figures to generate; mine is literally a huge iteration of close to 10,000 nodes/children.

I ended up following the instructions on this blog post (surely this info exists elsewhere as well) to 10 million (from the default 3 million).

$ kpsewhich texmf.cnf Then open the file as root with the command

$ sudo emacs /usr/share/texmf/web2c/texmf.cnf which will most likely prompt you for an administrator password. Enter the password and search for the line that begins with something such as

main_memory = 3000000 % words of inimemory available; also applies to inimf&mp Change the value “3000000″ to “10000000″, i.e. change from 3 million to 10 million. Save your edit and quit your editor. Then issue the command

$ sudo fmtutil-sys --all and compile the book again.

I have no idea if this is robust. For example, I use Arch Linux which will probably overwrite this setting on the next TexLive update.

For now, however, the solution is allowing me 8 levels deep in a tree with growth by 3's (summation from n=0 to n=8 of 3^n total nodes).