how to set log scale range

is it possible to set the range of matlab plot

        set(gca,'XTick',(6:2:14),'XTickLabel',(6:2:14),'YTick',(1E-30:1E2:1E-22),...
               'YTickLabel',(1E-30:1E2:1E-22));

However, it gives me wrong yticklabel, I want yticklabel like '1E-30', '1E-28', '1E-26', '1E-24', '1E-22'

what is the correct range (1E-30:1E2:1E-22) that i could use to define this?

[Stephen23]

Both the colon and linspace operators use linear steps. If you want logarithmically spaced values, then use logspace, e.g.:

>> logspace(-30,-22,5)
ans =
  1e-030  1e-028  1e-026  1e-024  1e-022

But for plotting you don't need to create these labels anyway: see Jan's answer.

[Megha]

Thank you stephen

Answer 1

[Jan]

yt = logspace(-30, -22, 5);
set(gca, 'XTick', 6:2:14, 'XTickLabel', 6:2:14, ...
         'YTick', yt, 'YTickLabel', yt, ...
         'XLim', [6, 14], 'YLim', [1e-30, 1e-22], ...
         'YScale', 'log');

Use logspace to get the Y-ticks. Set the ranges accordingly and set Y-scaling to logarithmic.

By the way: You do not have to define the tick labels, if they are the same as the tick values.

[Megha]

Oh! thanks Jan. could you please also explain how to give 'yticklabel' like 10^-30, 10^-28, 10^-26... and so on instead of using '1E-30', '1E-28', '1E-26'??

[Jan]

Set 'YTickLabel' to:

sprintfc('10^%d', log(yt))

In modern Matlab versions try e.g. also:

compose('10^%d', -30:2:22)

[Megha]

     yt = compose('10^%d', -2:1:3);
     set(gca, 'XTick', (1:1:6), 'XTickLabel', 1:1:6, ...
         'YTick', (1E-2:1E3), 'YTickLabel', yt);

please check this, it seems there is some error somewhere