matplotlib-users

[Matplotlib-users] xticks on semilogx zoom problem

[Ryan K. <rya...@gm...>]

I have a semilogx plot that I have zoomed into, so that there are no
xticks visible.  I can't seem to set the xticks to something that
isn't an integer power of 10.  I would actually prefer to set it to a
number that isn't displayed as 10^xxx, but I don't know how.

For example:

y=3Dsin(2*pi*f)
semilogx(f,y)
xlim([1.5,2.5])
xticks([1.75,2.0])
show()

has no xticks.

How do I fix this?

Thanks,

Ryan

[Matplotlib-users] Re: xticks on semilogx zoom problem

[Ryan K. <rya...@gm...>]

I'm a dork.

help xticks told me the solution (imagine that) - RTFdocstring.

make sure to include xticks([1.75,2.0],['1.75','2.0'])

On 4/28/06, Ryan Krauss <rya...@gm...> wrote:
> I have a semilogx plot that I have zoomed into, so that there are no
> xticks visible.  I can't seem to set the xticks to something that
> isn't an integer power of 10.  I would actually prefer to set it to a
> number that isn't displayed as 10^xxx, but I don't know how.
>
> For example:
>
> y=3Dsin(2*pi*f)
> semilogx(f,y)
> xlim([1.5,2.5])
> xticks([1.75,2.0])
> show()
>
> has no xticks.
>
> How do I fix this?
>
> Thanks,
>
> Ryan
>

Re: [Matplotlib-users] Re: xticks on semilogx zoom problem

[John H. <jdh...@ac...>]

>>>>> "Ryan" == Ryan Krauss <rya...@gm...> writes:

    Ryan> I'm a dork.  help xticks told me the solution (imagine that)
    Ryan> - RTFdocstring.

    Ryan> make sure to include xticks([1.75,2.0],['1.75','2.0'])


At first this example confused me, because normally

  xticks([1.75,2.0])

w/o the labels will do the right thing, ie put labels on 1.75 and
2.0.  The reason it doesn't in your example is that you are using a
semilogx plot, and thus the default formatter is
ticker.LogFormatterMathtext , which only places labels on the
decades.  This may be considered a bug, wart, or minor annoyance.  As
you note, there is an easy workaround.  

Alternatively, it might be better to change the formatter when there
is a call to set_ticks just as we currently change the locator


    def set_ticks(self, ticks):
        """
        Set the locations of the tick marks from sequence ticks

        ACCEPTS: sequence of floats
        """
        self.set_major_locator( FixedLocator(ticks) )

        self.get_view_interval().update(ticks,0)
        return self.get_major_ticks()

JDH