Package PGF Math Error: The function `add' already exists.

[diekmann]

Trying to compile the documentation with

pdflatex documentation.tex

I get the following error:

! Package PGF Math Error: The function `add' already exists.

See the PGF Math package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              

l.23 }

If I remove the pgfmath package, the error is

! Package pgfbase Error: Unsupported color model `'. Sorry.

See the pgfbase package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              

l.73    \node[router] (r1) at (.5,0) {};

pdflatex --version pdfTeX 3.1415926-2.5-1.40.14 (TeX Live 2013/Debian)

Ubuntu 14.04.3 LTS

[moepinet]

Bug in pgfmath. Fixed since texlive-2014.