# siunitx display uncertainty of zero

I would like to have uncertainties of zero (variance estimates) displayed:

\documentclass{article}
\usepackage{siunitx}
\begin{document}
\num[separate-uncertainty=true]{1 +- 0.0}
\end{document}


Actual rendering:

 1±


Hoping for:

 1±0.0

• I don't exactly remember the rules, but the number of decimal places should be the same: {1.0+-0.0} instead of {1+-0.0}. – campa Apr 7 '17 at 10:30
• I do not know if what you are doing is wrong, but I found this in the manual: \num[separate-uncertainty = true]{1.234(5)} – hpekristiansen Apr 7 '17 at 10:32
• @campa I see, \num[separate-uncertainty=true]{1.0 +- 0.0} works, but \num[separate-uncertainty=true]{1 +- 0} does not (no display at all?) – mrcalvin Apr 7 '17 at 11:11
• @hpekristiansen I am aware of that notational alternatives. Interestingly \num[separate-uncertainty=true]{1(0)} is ok, while {1 +- 0} is not? \num[separate-uncertainty=true]{1.0(0)} works also; \num[separate-uncertainty=true]{1.0(0.0)} does not, \num[separate-uncertainty=true]{1(0.0)} also renders void. – mrcalvin Apr 7 '17 at 11:15

A correct syntax consists in writing the uncertainty as an integer between parentheses. This is interpreted as a number with a decimal part having as many digits as the ‘main’ number.

Demo:

\documentclass{article}
\usepackage{siunitx}
\begin{document}

\sisetup{separate-uncertainty=true}
\begin{tabular}{ll}
\num{1.00 (10)} & \num{1.00 (2)} \\[2ex]
\num{1.0 (10)} & \num{1.0 (2)} \\[2ex]
\num{1 (10)} & \num{1 (2)}
\end{tabular}

\end{document}


• +1 You should show this working with a zero uncertainty. – Andrew Swann Apr 7 '17 at 12:05
• @Andrew Swann: Well, what happens, except an absurd uncertainty of $\pm0$? – Bernard Apr 7 '17 at 12:11
• Indeed it is absurd, but it was the OP is asking for. – Andrew Swann Apr 7 '17 at 12:12
• I agree with the absurdity of zero uncertainty, but the OP's code \num[separate-uncertainty=true]{1 +- 0.0} works for any uncertainty other than 0, e.g. \num[separate-uncertainty=true]{1 +- 0.1} so with the syntax the OP is using things go wrong specifically when the uncertainty is specified as 0 using a different number of decimal points (\num[separate-uncertainty=true]{1.0 +- 0.0} also works fine for example) – Dai Bowen Apr 7 '17 at 13:04
• a) as @DaiBowen points out, this is about inconsistent behavior and b) whether a zero uncertainty is absurd or not is to be judged in the context of reporting. – mrcalvin Apr 7 '17 at 13:16