1

I know that the title is not clear at all; the issue is that I'm trying to use the calc package to compute the value of a certain counter, and I receive two different error messages, according to some little changes that I do in the code. I have the impression both these issues come from something common that I'm not getting. I'll divide this thread into two points, each of them describing a different error, with the relative MWE.

1) The following code should print on the page the value 3 (because the decimal numbers disappear, according to the package documentation). Instead I receive the Missing number, treated as zero error. If I run the code despite the warning, on the paper will be printed a string composed by the characters 2! 5.

\documentclass[11pt, a4paper]{article}

\usepackage{calc}

\newcounter{a}

\begin{document}

\setcounter{a}{\ratio{7}{2}}
\thea

\end{document}

The complete message that appears in the terminal if I run this code is the following. I'll include what goes after I tell it to ignore the error and run either way (r).

alex@Sargon:~/Documenti/Progetto Perturbator/bin/mwe$ pdflatex mwe.tex
This is pdfTeX, Version 3.14159265-2.6-1.40.17 (TeX Live 2016/Debian) (preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode
(./mwe.tex
LaTeX2e <2017/01/01> patch level 3
Babel <3.9r> and hyphenation patterns for 83 language(s) loaded.
(/usr/share/texlive/texmf-dist/tex/latex/base/article.cls
Document Class: article 2014/09/29 v1.4h Standard LaTeX document class
(/usr/share/texlive/texmf-dist/tex/latex/base/size11.clo))
(/usr/share/texlive/texmf-dist/tex/latex/tools/calc.sty) (./mwe.aux)
! Missing number, treated as zero.
<to be read again> 
                   \ratio 
l.9     \setcounter{a}{\ratio{7}{2}}

? r
OK, entering \nonstopmode...

! Package calc Error: `7' invalid at this point.

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

l.9     \setcounter{a}{\ratio{7}{2}}

[1{/var/lib/texmf/fonts/map/pdftex/updmap/pdftex.map}] (./mwe.aux) )
(\end occurred inside a group at level 1)

### semi simple group (level 1) entered at line 9 (\begingroup)
### bottom level
(see the transcript file for additional information)</usr/share/texlive/texmf-d
ist/fonts/type1/public/amsfonts/cm/cmr10.pfb>
Output written on mwe.pdf (1 page, 10687 bytes).
Transcript written on mwe.log.

2) If I try to multiply the result of the \ratio command I receive an error which says Illegal unit of measure (pt inserted). The MWE, very similar, is the following:

\documentclass[11pt, a4paper]{article}

\usepackage{calc}

\newcounter{a}

\begin{document}

\setcounter{a}{2*\ratio{7}{2}}
\thea

\end{document}

Notice that in this case, despite the warning, if I run the code ignoring the alert I will actually see the expected value (7) printed on the paper. Again I'll include all the terminal's speech, including the part after (r).

alex@Sargon:~/Documenti/Progetto Perturbator/bin/mwe$ pdflatex mwe.tex
This is pdfTeX, Version 3.14159265-2.6-1.40.17 (TeX Live 2016/Debian) (preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode
(./mwe.tex
LaTeX2e <2017/01/01> patch level 3
Babel <3.9r> and hyphenation patterns for 83 language(s) loaded.
(/usr/share/texlive/texmf-dist/tex/latex/base/article.cls
Document Class: article 2014/09/29 v1.4h Standard LaTeX document class
(/usr/share/texlive/texmf-dist/tex/latex/base/size11.clo))
(/usr/share/texlive/texmf-dist/tex/latex/tools/calc.sty) (./mwe.aux)
! Illegal unit of measure (pt inserted).
<to be read again> 
                   !
l.9     \setcounter{a}{2*\ratio{7}{2}}

? r
OK, entering \nonstopmode...
! Illegal unit of measure (pt inserted).
<to be read again> 
                   !
l.9     \setcounter{a}{2*\ratio{7}{2}}

[1{/var/lib/texmf/fonts/map/pdftex/updmap/pdftex.map}] (./mwe.aux) )
(see the transcript file for additional information)</usr/share/texlive/texmf-d
ist/fonts/type1/public/amsfonts/cm/cmr10.pfb>
Output written on mwe.pdf (1 page, 8364 bytes).
Transcript written on mwe.log.

How to proceed? I carefully read all the parts related to the \ratio command on the package documentation, at least the ones I could get, and I really don't know what's wrong with this.

  • \ratio requieres a dimension, not a number. See documentation. – Marco Daniel Mar 19 '17 at 21:49
  • Depending on the use - case, \fpeval from xfp would be easier, perhaps – user31729 Mar 19 '17 at 22:07
  • 1
    Counters only accept integer values to begin with. What's the intended usage? This seems like an XY problem. – egreg Mar 19 '17 at 22:19
  • the value is converted to an integer at the end of the calculation, by cutting out the decimal part – il mietitore Mar 20 '17 at 8:59
4

\ratio needs to use dimension values, e.g. \ratio{7pt}{2pt}, but even this is not sufficient. In order to apply it with \setcounter or \setlength, there must be an explicit multiplication, with either some number or a length, see the examples below.

\documentclass[11pt, a4paper]{article}

\usepackage{calc}


\newlength{\foo}
\newcounter{a}
\newlength{\foobar}
\newlength{\foobarother}
\setlength{\foobar}{7pt}
\setlength{\foobarother}{2pt}



\begin{document}

\setcounter{a}{1*\ratio{7pt}{2pt}}
\setlength{\foo}{1pt*\ratio{\foobar}{\foobarother}}


\the\foo\ or \thea

\end{document}

The result is 3.5pt for \the\foo and 3 for \thea.

  • Brilliant! The terminal saying that the measure unit is wrong instead of it being missing is quite misleading, but anyway, cool that I figured this out – il mietitore Mar 20 '17 at 9:03
  • @ilmietitore: I am not sure I do understand you. The terminal says the measure unit is wrong? – user31729 Mar 20 '17 at 22:53
  • well, in the mwe it said Illegal unit of measure (pt inserted). If instead of being it's "illegal" it said it was plainly "missing" probably finding this sort of error would have been much simpler. – il mietitore Mar 21 '17 at 11:23

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