1

I am making a simple semi-logarithmic diagram, with axis set as

\begin{axis}[
ymin=0.25, ymax=1.1, % y scale
ymode=log,
]

Basically, it works, but with that settings produces tick labels like

$10^{0}$ (that is OK), and $10^{-0.2}$, $10^{-0.4}$

etc., equidistantly. With settings like

\begin{axis}[
ymin=0.1, ymax=1.1, % y scale
ymode=log,
]

everything works as expected. I guess that the problem is that the range spanned is less than a log(10). Do I wrong something or it is a known bug?

  • Why would you make a logarithmic plot over such a small range of values? A linear plot should be perfectly fine here. – JMP Jul 9 '16 at 19:53
  • Because I am displaying a kind of saturation curve, where the values approach more and more 1. On a linear scale, most of the points are at the same vertical position. The logarithmic behavior is independent of the range. – katang Jul 10 '16 at 6:27
1

That is expected behavior.

In particular, the scaling is correct: it is a log scale. What is unexpected at first glance is that the exponent is not an integer. That, in turn, is a result of the small axis range. But a small axis range is not "a problem".

If you want a bigger axis range, you an simply enlarge it. If you prefer integer exponents, you can use ytick distance=1 (or choose a list of tick positions using ytick={<list>}).

  • Well, I do need the range which is optimal for what I want to present. Enlarging it would waste diagram space and loose information. Anyhow, thanks for your reply. BTW: is the non-integer exponent the by-product of some internal conversion, or you did have some special goal with it? (It is the first time I see a logarithmic graph I cannot tell directly what is the value displayed, even if it is at a tickmark.) – katang Jul 10 '16 at 6:36
  • One more little problem. It looks like your package takes over local setting for printing numbers. Unfortunately, our local settings use "decimal comma" instead of "decimal point". I.e. I print "0,8" instead of "0.8", even if I am preparing English paper. Is there a setting in your package to change this? – katang Jul 10 '16 at 7:16
  • Regarding non-integer exponents: they are unusual -- except if you have very small ranges. There is little to be done if you want to see any kind of description – Christian Feuersänger Jul 12 '16 at 18:37
  • Regarding comma/point: try using \pgfkeys{/pgf/number format/use comma} in the document's preamble. It should change the global appearance of all number formatting routines of PGF and pgfplots. The reference for all kinds of number formatting options is in pgfplotstable.pdf or, equivalently, in pgfmanual.pdf. A brief summary is in pgfplots.pdf. – Christian Feuersänger Jul 12 '16 at 18:39

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