Re: histogram with logscale ...

[Pantxo]

address@hidden wrote
> Dear listmembers,
> 1.) trying to achieve a logscaling on the y-axis of a plot using "hist"
> gives me the result as attached in "Screenshot_histogram_logscale.jpg".
> The only difference between both commands consists of the additional
> setting 
> 
> set (gca,'yscale', 'log');
> 
> Could some kind soul suggest a way how to get the same coloured bargraphs
> as in the linear y-axis case?
> 
> 2.) Is there any means to dump the gnuplot-parameter data that are piped
> to gnuplot into a file? I tried the "rough" way by renaming the
> corresponding binary and writing stdout from octave into a file, however,
> this did not yield the expected results. The reason for this: I need
> modifications to the graph, straightforward achievable through gnuplot
> directly, impossble (much effort at least ....) through octave.
> 
> Thank you very much for your efforts,
> best regards
> 
> Dieter Jurzitza
> 
> 
> _______________________________________________
> Help-octave mailing list

> Help-octave@

> https://lists.gnu.org/mailman/listinfo/help-octave
> 
> 
> Screenshot_histogram_linscale.jpg (168K)
> <http://octave.1599824.n4.nabble.com/attachment/4685756/0/Screenshot_histogram_linscale.jpg>
> Screenshot_histogram_logscale.jpg (126K)
> <http://octave.1599824.n4.nabble.com/attachment/4685756/1/Screenshot_histogram_logscale.jpg>

The problem is that bars (actually patch objects) are drawn with 0 as bottom
y coordinates. Here is a hack that works for me in 4.2.1 (but not in the
latest dev version strangely):

data = rand (5,3);
h = bar (data)

## Get the patch objects and replace 0 coordinates by the minimal value you
want to be displayed
ymin = 1e-3;

hpa = get (h, "children");
data = get (cell2mat (hpa), "ydata");
for ii = 1:numel (data)
  tmp = data{ii};
  tmp(tmp == 0) = ymin;
  data{ii} = tmp;
endfor

set (cell2mat (hpa), {"ydata"}, data);
set (gca, "yscale", "log")
ylim ([ymin 1])

This is ugly I admit but I can't think of a better workaround ATM.

Pantxo



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